Researchers Database

MIKATA Yuji

    Faculty Division of Engineering Research Group of Engineering Professor
Last Updated :2021/07/07

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Research Areas

  • Nanotechnology/Materials, Inorganic and coordination chemistry
  • Life sciences, Bioorganic chemistry
  • Nanotechnology/Materials, Structural/physical organic chemistry

Research Experience

  • Apr. 2015 Mar. - 2021, 奈良女子大学研究院自然科学系教授
  • Apr. 2012 Mar. - 2015, 奈良女子大学研究院自然科学系准教授
  • Apr. 2001 Mar. - 2012, Nara Women's University, Associate Professor
  • Sep. 1999 Aug. - 2001, 日本学術振興会海外特別研究員(マサチューセッツ工科大学博士研究員)
  • Jun. 1993 Mar. - 2001, Nara Women's University, Research Associate
  • Apr. 1993 May - 1993, 日本学術振興会特別研究員-PD
  • Apr. 1992 Mar. - 1993, JSPS Pre- and Postdoctral Fellow
  • Apr. 2021, Nara Women's University

Education

  • - 1993, Kyoto University, Graduate School, Division of Natural Science, 化学
  • - 1988, Kobe University, Faculty of Science, 化学

Awards

  • The SPACC Award, Yuji Mikata, Society of Pure and Applied Coordination Chemistry, Oct. 2010
  • 有機合成化学協会 味の素研究企画賞「C-グリコシド結合を介した糖質への金属イオンの集積化と環境調和型分子変換プロセスへの展開」, Feb. 2003
  • 有機合成化学協会 塩野義製薬研究企画賞「マルチ機能抗腫瘍性金属錯体の開発と機能評価」, 有機合成化学協会, Feb. 1998

Published Papers

  • Conversion of (µ-OH)2Mn2(II,II) complex to (µ-O)2Mn2(III,III) core supported by a quinoxaline-based tetranitrogen ligand

    Yuji Mikata; Kana Murakami; Ayaka Ochi; Fumie Nakagaki; Kyoko Naito; Arimasa Matsumoto; Ryoji Mitsuhashi; Masahiro Mikuriya

    © 2020 Elsevier B.V. Quinoxaline-based tetranitrogen ligand, N,N’-bis(2-quinoxalylmethyl)-N,N’-dimethylethylenediamine (L9), stabilizes the bis(µ-hydroxo) dinuclear manganese(II,II) core. Oxidation of the complex with hydrogen peroxide in methanol suspension affords the bis(µ-oxo) dinuclear manganese(III,III) complex. The quinoxaline-based tripod ligand, tris(2-quinoxalylmethyl)amine (L11), did not afford corresponding bis(hydroxo) dimanganese(II,II) complex due to the subsequent atmospheric oxygen-promoted oxidation in the reaction solution similar to its quinoline counterpart, tris(2-quinolylmethyl)amine (L10). The solid state structures of [Mn(II)Cl2(L9)], [(µ-OH)2Mn2(II,II)(L9)2]2+, [(µ-O)2Mn2(III,III)(L9)2]2+, [(µ-O)2Mn2(III,III)(L11)2]2+, and [(µ-O)2Mn2(III,III)(L10)2]2+ complexes were determined by X-ray crystallography. The magnetic susceptibility measurement of (µ-OH)2Mn2(II,II) complex and electrochemical oxidation of (µ-O)2Mn2(III,III) complexes were performed to evaluate the tetramine ligand effect stabilizing the low oxidation states of dinuclear metal center supported by two oxygen atom bridges., Elsevier BV, 01 Sep. 2020, Inorganica Chimica Acta, 509, 119688 - 119688, doi;scopus;scopus_citedby

    Scientific journal

  • A Tetrakisquinoline Analog of Calcium Indicator Quin2 for Fluorescence Detection of Cd2+

    Yuji Mikata; Minori Kaneda; Marin Tanaka; Satoshi Iwatsuki; Hideo Konno; Arimasa Matsumoto

    © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Quin2 (2-{2-[bis(carboxymethyl)amino-5-methylphenoxy]methyl}-6-methoxy-8-[bis(carboxymethyl)amino]quinoline) is a well-known fluorescent Ca2+ indicator. In this study, we replaced its four carboxy groups with quinolines and deleted a methyl group on the benzene ring to afford TQquin2 [N,N,N',N'-tetrakis(2-quinolylmethyl)-8-amino-2-(2-aminophenoxy)methyl-6-methoxyquinoline]. In methanol solution, TQquin2 exhibited fluorescence enhancement toward Cd2+ with excellent selectivity., 08 Mar. 2020, European Journal of Inorganic Chemistry, 2020 (9), 757 - 763, doi;scopus;scopus_citedby

    Scientific journal

  • Quinoline- and isoquinoline-derived ligand design on TQEN (N,N,N',N'-tetrakis(2-quinolylmethyl)ethylenediamine) platform for fluorescent sensing of specific metal ions and phosphate species.

    Yuji Mikata

    Rational molecular structure alterations of TQEN (N,N,N',N'-tetrakis(2-quinolylmethyl)ethylenediamine) produced variable fluorescent sensors for specific metal ions and phosphate species. Utilization of methoxy-substituted quinoline and isoquinoline chromophores, conformational restriction and multidentate coordination structure allow discrimination between Zn2+ and Cd2+. Pyrophosphate (P2O74-, PPi) and phosphate (PO43-) also are selectively detected with dinuclear Zn2+ complexes of tetrakisquinoline-based ligands. Differential stability and structure of the metal complexes, as well as resulting fluorescence enhancement mechanism, such as intramolecular excimer formation via change in coordination geometry, play key roles in the discrimination of target ions., Royal Society of Chemistry (RSC), 22 Dec. 2020, Dalton transactions (Cambridge, England : 2003), 49 (48), 17494 - 17504, True, doi;pubmed;url;scopus;scopus_citedby

    Scientific journal

  • Switching of Fluorescent Zn/Cd Selectivity in N, N, N′, N′-Tetrakis(6-methoxy-2-quinolylmethyl)-1,2-diphenylethylenediamine by One Asymmetric Carbon Atom Inversion

    Yuji Mikata; Kana Nozaki; Marin Tanaka; Hideo Konno; Arimasa Matsumoto; Masaya Kawamura; Shin Ichiro Sato

    © 2020 American Chemical Society. A quinoline-based hexadentate ligand, (S,S)-N,N,N′,N′-tetrakis(6-methoxy-2-quinolylmethyl)-1,2-diphenylethylenediamine ((S,S)-6-MeOTQPh2EN), exhibits fluorescence enhancement at 498 nm upon addition of 1 equiv of Zn2+ (IZn/I0 = 12, φZn = 0.047) in aqueous DMF solution (DMF/H2O = 2:1). Addition of 1 equiv of Cd2+ affords a much smaller fluorescence increase at the same wavelength (ICd/I0 = 2.5, ICd/IZn = 21%). The trivalent metal ions such as Al3+, Cr3+, and Fe3+ also exhibit fluorescence enhancement at 395 nm (IAl/I0 = 22, ICr/I0 = 6 and IFe3+/I0 = 13). In contrast, meso-6-MeOTQPh2EN exhibits a Cd2+-selective fluorescence increase at 405 nm in the presence of 1 equiv of metal ion (ICd/I0 = 11.5, φCd = 0.022), while Zn2+ induces a smaller fluorescent response under the same experimental conditions (IZn/I0 = 3.3, IZn/ICd = 29%). In this case, the fluorescence intensities of meso-6-MeOTQPh2EN in the presence of a large amount of Zn2+ and Cd2+ become similar. This diastereomer-dependent, fluorescent metal ion specificity is derived from the Zn2+-specific intramolecular excimer formation in (S,S)-6-MeOTQPh2EN-Zn2+ complex and higher binding affinity of meso-6-MeOTQPh2EN with Cd2+ in comparison to Zn2+. The more conformationally restricted diastereomeric pair, namely, cis- and trans-TQDACHs (cis- and trans-N,N,N′,N′-tetrakis(2-quinolylmethyl)-1,2-diaminocyclohexanes), both exhibit Zn2+-specific fluorescence enhancement because of the high metal binding affinity and intramolecular excimer forming property derived from the rigid DACH backbone., 2020, Inorganic Chemistry, doi;scopus;scopus_citedby

    Scientific journal

  • A basic study of photodynamic therapy with glucose-conjugated chlorin e6 using mammary carcinoma xenografts

    Tomohiro Osaki; Shota Hibino; Inoru Yokoe; Hiroaki Yamaguchi; Akihiro Nomoto; Shigenobu Yano; Yuji Mikata; Mamoru Tanaka; Hiromi Kataoka; Yoshiharu Okamoto

    © 2019, MDPI AG. All rights reserved. By using the Warburg effect-a phenomenon where tumors consume higher glucose levels than normal cells-on cancer cells to enhance the effect of photodynamic therapy (PDT), we developed a new photosensitizer, glucose-conjugated chlorin e6 (G-Ce6). We analyzed the efficacy of PDT with G-Ce6 against canine mammary carcinoma (CMC) in vitro and in vivo. The pharmacokinetics of G-Ce6 at 2, 5, and 20 mg/kg was examined in normal dogs, whereas its intracellular localization, concentration, and photodynamic effects were investigated in vitro using CMC cells (SNP cells). G-Ce6 (10 mg/kg) was administered in vivo at 5 min or 3 h before laser irradiation to SNP tumor-bearing murine models. The in vitro study revealed that G-Ce6 was mainly localized to the lysosomes. Cell viability decreased in a G-Ce6 concentration- and light intensity-dependent manner in the PDT group. Cell death induced by PDT with G-Ce6 was not inhibited by an apoptosis inhibitor. In the in vivo study, 5-min-interval PDT exhibited greater effects than 3-h-interval PDT. The mean maximum blood concentration and half-life of G-Ce6 (2 mg/kg) were 15.19 ± 4.44 µg/mL and 3.02 ± 0.58 h, respectively. Thus, 5-min-interval PDT with G-Ce6 was considered effective against CMC., May 2019, Cancers, 11 (5), doi;scopus;scopus_citedby

    Scientific journal

  • C60 Fullerene with Tetraethylene Glycols as a Well-defined Soluble Building Block and Saccharide-conjugation Producing PDT Photosensitizer

    Atsushi Narumi; Tatsufumi Nakazawa; Kosuke Shinohara; Hiroki Kato; Yoshinori Iwaki; Haruya Okimoto; Moriya Kikuchi; Seigou Kawaguchi; Shodai Hino; Atsushi Ikeda; Montaser Shaykoon Ahmed Shaykoon; Xiande Shen; Qian Duan; Toyoji Kakuchi; Kazuma Yasuhara; Akihiro Nomoto; Yuji Mikata; Shigenobu Yano

    © 2019 The Chemical Society of Japan. Tetraethylene glycol (TEG)-conjugated (C60-Ih)[5,6]fullerene (TEG-C60) was synthesized as a soluble molecular building block generating C60-based conjugates with advanced properties. The improved solubility allowed the glycosylation reaction with TEG-C60 using a Lewis acid in chloroform at low temperature. The resultant glycoconjugated TEG-C60 was characterized in terms of water solubility, ability to generate reactive oxygen species (ROS), and photodynamic activity., 2019, Chemistry Letters, 48 (10), 1209 - 1211, doi;scopus;scopus_citedby

    Scientific journal

  • Methoxy-substituted tetrakisquinoline analogs of EGTA and BAPTA for fluorescence detection of Cd 2+

    Yuji Mikata; Minori Kaneda; Hideo Konno; Arimasa Matsumoto; Shin Ichiro Sato; Masaya Kawamura; Satoshi Iwatsuki

    © The Royal Society of Chemistry. EGTA (ethylene glycol bis(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid) and BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid) are well-known Ca 2+ chelators that have four carboxylates, two nitrogen atoms and two ether oxygen atoms. In the present study, we prepared EGTQ (N,N,N′,N′-tetrakis(2-quinolylmethyl)-1,2-bis(2-aminoethoxy)ethane) and BAPTQ (N,N,N′,N′-tetrakis(2-quinolylmethyl)-1,2-bis(2-aminophenoxy)ethane) as quinoline alternatives of EGTA and BAPTA, respectively. In methanol-HEPES buffer solution (9 : 1, 50 mM HEPES, 0.1 M KCl, pH = 7.5), EGTQ exhibits fluorescence enhancement induced by Zn 2+ and Cd 2+ with poor selectivity, but BAPTQ did not exhibit a fluorescence response to either metal ion. Introduction of three methoxy substituents at the 5,6,7-positions of each quinoline moiety in BAPTQ specifically enhanced the fluorescence intensity of the Cd 2+ complex, establishing the Cd 2+ -specific probe TriMeOBAPTQ (N,N,N′,N′-tetrakis(5,6,7-trimethoxy-2-quinolylmethyl)-1,2-bis(2-aminophenoxy)ethane). In contrast, TriMeOEGTQ (N,N,N′,N′-tetrakis(5,6,7-trimethoxy-2-quinolylmethyl)-1,2-bis(2-aminoethoxy)ethane) maintains a poor Cd 2+ /Zn 2+ selectivity in its fluorescence response. Although the crystal structures of Cd 2+ /Zn 2+ complexes with EGTQ and BAPTQ derivatives reveal the formation of multiple components including mononuclear and dinuclear complexes, the dinuclear Cd 2+ and Zn 2+ complexes with a linearly extended structure are regarded as possible fluorescent species in the solution. The conformational restriction of BAPTQ due to the orthophenylene moieties in the molecular skeleton is responsible for the formation of the weakly fluorescent, OH-bridged dizinc complex, which is critical to the strict Cd 2+ -specificity in the fluorescence response of TriMeOBAPTQ., 2019, Dalton Transactions, 48 (12), 3840 - 3852, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Pyrophosphate-Induced Intramolecular Excimer Formation in Dinuclear Zinc(II) Complexes with Tetrakisquinoline Ligands

    Yuji Mikata; Risa Ohnishi; Risa Nishijima; Arimasa Matsumoto; Hideo Konno

    © 2018 American Chemical Society. Dinuclear Zn2+ complexes with HTQHPN (N,N,N′,N′-tetrakis(2-quinolylmethyl)-2-hydroxy-1,3-propanediamine) derivatives have been prepared, and their pyrophosphate (PPi, P2O74-) sensing properties were examined. The ligand library includes six HTQHPN derivatives with electron-donating/withdrawing substituents, an extended aromatic ring, and six-membered chelates upon zinc binding. Complexation of ligand with 2 equiv of Zn2+ promotes small to moderate fluorescence enhancement around 380 nm, but in the cases of HTQHPN, HT(6-FQ)HPN (N,N,N′,N′-tetrakis(6-fluoro-2-quinolylmethyl)-2-hydroxy-1,3-propanediamine), and HT(8Q)HPN (N,N,N′,N′-tetrakis(8-quinolylmethyl)-2-hydroxy-1,3-propanediamine), subsequent addition of PPi induced a significant fluorescence increase around 450 nm. This fluorescence enhancement in the long-wavelength region is attributed to the conformational change of the bis-(quinolylmethyl)amine moiety which promotes intramolecular excimer formation between adjacent quinolines upon binding with PPi. The structures of PPi- and phosphate-bound dizinc complexes were revealed by X-ray crystallography utilizing phenyl-substituted analogues. The zinc complex with HT(8Q)HPN exhibits the highest signal enhancement (IPPi/I0 = 12.5) and selectivity toward PPi sensing (IATP/IPPi = 20% and IADP/IPPi = 25%). The fluorescence enhancement turned to decrease gradually after the addition of more than 1 equiv of PPi due to the removal of zinc ion from the ligand-zinc-PPi ternary complex, allowing the accurate determination of PPi concentrations at the fluorescence maximum composition. The practical application of the present method was demonstrated monitoring the enzymatic activity of pyrophosphatase., 02 Jul. 2018, Inorganic Chemistry, 57 (13), 7724 - 7734, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Carbohydrate-Appended TQNPEN [N,N,N′,N′-Tetrakis(2-quinolylmethyl)-3-aza-1,5-pentanediamine] Derivatives for Fluorescence Detection of Intracellular Cd2+

    Yuji Mikata; Kana Nozaki; Minori Kaneda; Keiko Yasuda; Masato Aoyama; Satoshi Tamotsu; Arimasa Matsumoto

    © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Carbohydrate-appended TQNPEN [N,N,N′,N′-tetrakis(2-quinolylmethyl)-3-aza-1,5-pentanediamine] derivatives were developed as intracellular fluorescent Cd2+ sensors. Glucose (L1), galactose (L2), and maltose (L3) were utilized as sugar moieties. All glycosylated derivatives exhibit a fluorescence increase (ICd/I0 = 11–25) at 415 nm upon addition of 1 equiv. of Cd2+; however, 1 equiv. of Zn2+ induces negligible fluorescence change due to weak metal–ligand interaction (IZn/I0 = 3, IZn/ICd = 11–31 %). The properties of the Cd2+ complex with parent TQNPEN, including maximum fluorescence wavelength and lifetime, Cd2+ specificity of the fluorescence, and strong metal binding affinity, were well preserved in L1–L3. The intracellular Cd2+ detection was successfully achieved by glucose- and galactose-appended derivatives L1 and L2, likely due to enhanced cell membrane permeability and intracellular distribution in HeLa cells., 29 Jun. 2018, European Journal of Inorganic Chemistry, 2018 (24), 2755 - 2761, doi;scopus;scopus_citedby

    Scientific journal

  • Synthesis and antifungal activities of pyridine bioisosteres of a bismuth heterocycle derived from diphenyl sulfone

    A. F.M. Hafizur Rahman; Toshihiro Murafuji; Kazuki Yamashita; Masahiro Narita; Isamu Miyakawa; Yuji Mikata; Katsuya Ishiguro; Shin Kamijo

    © 2018 The Japan Institute of Heterocyclic Chemistry. – Heterocyclic iodobismuthanes 7–9 [IBi(C6H4-2-SO2C5H3N-1´-)] derived from phenyl pyridinyl sulfones were synthesized. Their antifungal activities against the yeast Saccharomyces cerevisiae were compared with those of halobismuthanes [XBi(RC6H3-2-SO2C6H4-1´-)] (1: X=Cl; 2: X=I, R=H) derived from diphenyl sulfone derivatives to determine how the bioisosteric replacement of the benzene ring in 2 with the pyridine ring in 7–9 affects their activities. The antifungal activities of 7–9 were higher or comparable to those of 1 and 2. The DFT calculations suggested that the generation of the antifungal activity of the bismuthanes was well understood by the nucleophilic addition of methanethiolate anion as a model biomolecule at the bismuth atom to give an intermediate ate complex., 2018, Heterocycles, 96 (6), 1037 - 1052, doi;scopus;scopus_citedby

    Scientific journal

  • Substituent effects on the crystal structures of salts prepared from (R)-2-methoxy-2-(1-naphthyl)- propanoic acid and (R)-1-arylethylamines

    Akio Ichikawa; Hiroshi Ono; Yuji Mikata

    © 2017 by the authors. The crystal structures of salts 6-9 prepared from (R)-2-methoxy-2-(1-naphthyl)propanoic acid [(R)-MαNP acid, (R)-1] and (R)-1-arylethylamines [salt 6, (R)-1-(4-methoxyphenyl) ethylamine ·(R)-1; salt 7, (R)-1-(4-fluorophenyl)ethylamine·(R)-1; salt 8, (R)-1-(4-chlorophenyl) ethylamine·(R)-1; and salt 9, (R)-1-(3-chlorophenyl)ethylamine·(R)-1] were elucidated by X-ray crystallography. The solid-state associations and conformations of the MαNP salts were defined using the concepts of supramolecular- and planar chirality, respectively, and the crystal structures of salts 6-9 were interpreted as a three-step hierarchical assembly. The para-substituents of the (R)-1-arylethylammonium cations were found on sheet structures consisting of 21 columns. Thus, salts possessing smaller para-substituents, that is, salt 7 (p-F) and salt 9 (p-H), and larger para-substituents, that is, salt 6 (p-OMe) and salt 8 (p-Cl), crystallized in the space groups P21 and C2, respectively. Additionally, weak intermolecular interactions, that is, aromatic C-H…π, C-H…F, and C-H…O interactions, were examined in crystalline salts 6-9., Sep. 2017, Crystals, 7 (9), 263, doi;scopus;scopus_citedby

    Scientific journal

  • TQOPEN (N,N,N′,N′-Tetrakis(2-quinolylmethyl)-3-oxa-1,5-pentanediamine) Family as Heptadentate Fluorescent Cd2+ Sensors

    Yuji Mikata; Asako Kizu; Kana Nozaki; Hideo Konno; Hiroshi Ono; Shunsuke Mizutani; Shin Ichiro Sato

    © 2017 American Chemical Society. A quinoline-based heptadentate ligand, N,N,N′,N′-tetrakis(2-quinolylmethyl)-3-oxa-1,5-pentanediamine (TQOPEN), exhibits a fluorescence increase (ICd/I0 = 25, ?Cd = 0.017) at 428 nm upon addition of 1 equiv of Cd2+. In contrast, 1 equiv of Zn2+ induces a negligible fluorescence change due to weak interaction (IZn/I0 = 2.5, IZn/ICd = 10%). In comparison with TQOPEN, the thia and aza derivatives TQSPEN and TQNPEN exhibit improved Cd2+/Zn2+ selectivity and higher Cd2+-binding affinity, respectively. The solid-state structures of mononuclear Cd2+ and hydroxide-bridged dinuclear Zn2+ complexes of TQOPEN were elucidated by X-ray crystallography. Although the crystal structure of the TQOPEN-Cd2+ complex exhibits a six-coordinate metal center, in which one quinoline weakly interacts with the Cd center (Cd···Nquinoline = 3.303(3) Å), a 1H NMR study at 233 K suggests that all quinolines interact with the Cd center to form a symmetrical seven-coordinate structure in solution. Theoretical calculations (TDDFT) support the flexible coordination environment around the Cd center, leading to intramolecular excimer formation with two quinoline moieties in the excited state. The importance of a heptadentate structure was further demonstrated by the lack of Cd2+ specificity with hexadentate ligands TriQOPEN (N,N,N′-tris(2-quinolylmethyl)-3-oxa-1,5-pentanediamine) and TQCPEN (N,N,N′,N′-tetrakis(2-quinolylmethyl)-1,5-pentanediamine)., AMER CHEMICAL SOC, 03 Jul. 2017, Inorganic Chemistry, 56 (13), 7404 - 7415, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Replacement of quinolines with isoquinolines affords target metal ion switching from Zn2+ to Cd2+ in the fluorescent sensor TQLN (N,N,N′,N′-tetrakis(2-quinolylmethyl)-2,6-bis(aminomethyl)pyridine)

    Yuji Mikata; Ayaka Takekoshi; Minori Kaneda; Hideo Konno; Keiko Yasuda; Masato Aoyama; Satoshi Tamotsu

    © The Royal Society of Chemistry. A quinoline-based heptadentate ligand, N,N,N′,N′-tetrakis(2-quinolylmethyl)-2,6-bis(aminomethyl)pyridine (TQLN), exhibits a Zn2+-specific fluorescence increase at 428 nm, which is assigned to excimer emission (IZn/I0 = 38, ICd/IZn = 24%, ϕZn = 0.069). In contrast, the isoquinoline counterpart 1-isoTQLN exhibits a Cd2+-specific fluorescence increase at 365 nm attributable to monomer emission (ICd/I0 = 83, IZn/ICd = 19%, ϕCd = 0.015)., ROYAL SOC CHEMISTRY, 2017, Dalton Transactions, 46 (3), 632 - 637, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • The crystal structure of the more-soluble Mosher's salt

    Akio Ichikawa; Hiroshi Ono; Yuji Mikata

    © 2017 The Chemical Society of Japan. The crystal structure of salt 4 prepared from (S)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid [(S)-MTPA, (S)-1] and (R)-1-phenylethylamine [(R)-PEA, (R)-2] was determined using X-ray crystallography. The (S)-MTPA anion showed an unusual conformation. The closest ion-pair joined with a methoxy-group-assisted salt bridge and aromatic C·H···π interaction in a unique supR association. The aromatic C·H···π interactions between the 21 columns were not effective. These results clarified the mechanism of Mosher's enantioresolution of (RS)-1 with (R)-2 in combination with the previously reported crystal structure of the diastereomeric salt 3 [(R)-1·(R)-2]., 2017, Chemistry Letters, 46 (4), 550 - 553, doi;scopus;scopus_citedby

    Scientific journal

  • Synthesis and structural characterization of diazulenylborinic acid

    Toshihiro Murafuji; Kohhei Shintaku; Kouhei Nagao; Yuji Mikata; Katsuya Ishiguro; Shin Kamijo

    © 2017 The Japan Institute of Heterocyclic Chemistry. Diazulenylborinic acid 1 was synthesized by the reaction of 1,3-dibromoazulen-2-yllithium (2) with 1,3-dibromoazulen-2-ylboronic acid ethylene glycol ester (7d). The X-Ray crystallographic study of 1 revealed that it forms a dimeric structure through intermolecular hydrogen bonding between the hydroxyl groups. To obtain the tetracoordinate borinate derivative from 1, the attempted esterification of 1 with N,N-dimethylethanolamine did not give corresponding borinate 8 but resulted in the unexpected protodeboronation to give parent 1,3-dibromoazulene (4). The 13C and 11B NMR studies of 1 in the presence of Et3N revealed the change in the φ-polarization of the azulenyl group accompanied by the change in the geometry of the boron to a tetracoordinate structure., 2017, Heterocycles, 94 (4), 676 - 690, doi;scopus;scopus_citedby

    Scientific journal

  • Intramolecular [2 + 2] and [4 + 2] Cycloaddition Reactions of Cinnamylamides of Ethenetricarboxylate in Sequential Processes

    Shoko Yamazaki; Hirotaka Sugiura; Shinnosuke Ohashi; Keisuke Ishizuka; Rina Saimu; Yuji Mikata; Akiya Ogawa

    © 2016 American Chemical Society. Intramolecular [2 + 2] and [4 + 2] cycloaddition reactions of cinnamylamides of ethenetricarboxylate in sequential processes have been studied. Reaction of 1,1-diethyl 2-hydrogen ethenetricarboxylate and trans-cinnamylamines in the presence of EDCI/HOBt/Et3N led to pyrrolidine products in one pot, via intramolecular [2 + 2], [4 + 2], and some other cyclizations. The types of the products depend on the substituents on the benzene ring and the reaction conditions. Reaction of cinnamylamines without substituents on the benzene ring and with halogens and OMe on the para position at room temperature gave cyclobutane-fused pyrrolidines as major products via [2 + 2] cycloaddition. The reaction at 80 °C in 1,2-dichloroethane gave δ-lactone fused pyrrolidines as major products, probably via ring-opening of the cyclobutanes. Interestingly, reaction of 1,1-diethyl 2-hydrogen ethenetricarboxylate and cinnamylamines bearing electron-withdrawing groups such as NO2, CN, CO2Me, CO2Et, and CF3 on ortho and para positions in the presence of EDCI/HOBt/Et3N at room temperature or at 60-80 °C gave tetrahydrobenz[f]isoindolines via [4 + 2] cycloaddition as major products. DFT studies have been performed to explained the observed [2 + 2]/[4 + 2] selectivity., 18 Nov. 2016, Journal of Organic Chemistry, 81 (22), 10863 - 10886, doi;scopus;scopus_citedby

    Scientific journal

  • Fluorescent Detection of Phosphate Ion via a Tetranuclear Zinc Complex Supported by a Tetrakisquinoline Ligand and μ4-PO4 Core

    Yuji Mikata; Risa Ohnishi; Risa Nishijima; Hideo Konno

    © 2016 American Chemical Society. The tetrakisquinoline ligand HT(6-MeO8Q)HPN (N,N,N′,N′-tetrakis(6-methoxy-8-quinolylmethyl)-2-hydroxy-1,3-propanediamine) exhibited Zn2+-induced fluorescence enhancement with high specificity and sensitivity (IZn/I0 = 57 and ICd/IZn = 6% in the presence of 2 equiv of Zn2+ LOD (limit of detection) = 15 nM). This ligand also exhibited fluorescence enhancement specific to inorganic phosphate (PO43-) in DMF-HEPES buffer (50 mM HEPES, 100 mM KCl, pH = 7.5) (1:1) in the presence of 2 equiv of Zn2+. The structure of the unprecedented tetranuclear zinc complex with a μ4-PO4 bridge was elucidated by X-ray crystallography as the key species responsible for fluorescence enhancement., 07 Nov. 2016, Inorganic Chemistry, 55 (21), 11440 - 11446, doi;scopus;scopus_citedby

    Scientific journal

  • OFF-ON-OFF fluorescent response of N,N,N′,N′-tetrakis(1-isoquinolylmethyl)-2-hydroxy-1,3-propanediamine (1-isoHTQHPN) toward Zn2+

    Yuji Mikata; Risa Ohnishi; Anna Ugai; Hideo Konno; Yasushi Nakata; Ikuko Hamagami; Shin Ichiro Sato

    © The Royal Society of Chemistry 2016. An isoquinoline-based ligand, N,N,N′,N′-tetrakis(1-isoquinolylmethyl)-2-hydroxy-1,3-propanediamine (1-isoHTQHPN), exhibits a fluorescence increase at 475 nm upon addition of 1 equiv. of Zn2+ (IZn/I0 = 12, φZn = 0.023). This fluorescence enhancement turns and then decreases sharply after the addition of more than 1 equiv. of Zn2+ reaching a constant minimum intensity with more than 2 equiv. of Zn2+. In contrast, the fluorescence intensity at 353 nm continues to increase until the signal saturates at ca. 5 equiv. of Zn2+. This observation can be explained by the formation of a fluorescent mononuclear complex ([Zn(1-isoHTQHPN)]2+) followed by a non-fluorescent dinuclear complex ([Zn2(1-isoTQHPN)]3+) at 475 nm during the titration of 1-isoHTQHPN with Zn2+. Both the mono- and dinuclear complexes were characterized by UV-vis, fluorescence, 1H NMR, ESI-MS, X-ray crystallography and TDDFT calculations. The fluorescence enhancement at 475 nm is Zn2+-specific; Cd2+ induces a much smaller emission increase (ICd/I0 = 3.7, ICd/IZn = 31%). The Zn2+/Cd2+ selectivity of the fluorescent response correlates with the difference in excimer-forming ability derived from the Cd-Nisoquinoline and Zn-Nisoquinoline bond distances., 07 May 2016, Dalton Transactions, 45 (17), 7250 - 7257, doi;scopus;scopus_citedby

    Scientific journal

  • Inter- and intramolecular diels-alder reaction of ethenetricarboxylate derivatives

    Shoko Yamazaki; Hirotaka Sugiura; Mamiko Niina; Yuji Mikata; Akiya Ogawa

    © 2016 The Japan Institute of Heterocyclic Chemistry. Inter- and intramolecular [4+2] cycloaddition reactions of highly electron-deficient ethenetricarboxylates have been studied. Intermolecular Diels-Alder reaction of ethenetricarboxylate esters and cyclopentadiene proceeded at room temperature or -20 °C to give cycloadducts with 1:1.5-1.9 endo:exo ratio. Lewis acids such as EtAlCl2, Zn(OTf)2 and Cu(OTf)2 catalyzed reaction at room temperature or -40 °C gave cycloadducts with 3.1-5.4:1 endo:exo ratio. Reaction of N-benzyl- or N-allyl-2-furylmethylamine and 1,1-diethyl 2-hydrogen ethenetricarboxylate in the presence of EDCI/HOBt/Et3N at room temperature led directly to an intramolecular Diels-Alder adduct stereoselectively. The observed stereoselectivities were explained by the use of DFT calculations., 2016, Heterocycles, 92 (3), 485 - 510, doi;scopus;scopus_citedby

    Scientific journal

  • Off-On, Ratiometric, and On-Off Fluorescence Responses of Thioether-Linked Bisquinolines toward Hg2+ and Fe3+ Ions

    Yuji Mikata; Kaori Nakanishi; Fumie Nakagaki; Asako Kizu; Hideo Konno

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Fifteen bisquinoline derivatives with a thioether linker have been prepared, and their Hg2+- and Fe3+-specific fluorescence responses have been investigated. Upon the addition of Hg2+ ions, unsubstituted 2-quinolylmethyl derivatives 1a-1c exhibit a fluorescence enhancement (off-on) response. On the other hand, ratiometric and fluorescence quenching (on-off) responses are accomplished for derivatives with monomethoxy (2a-2c) and trimethoxy (3a-3c) substituents on the aromatic ring, respectively. The 8-quinolylmethyl derivatives 4a-4c and 5a-5c exhibit a similar response pattern to those of 1 and 2 with enhanced Hg2+ ion selectivity. Increasing the number of sulfur atoms through the extension of the linker chain also improves the Hg2+ ion selectivity., 01 Aug. 2015, European Journal of Inorganic Chemistry, 2015 (22), 3769 - 3780, doi;scopus;scopus_citedby

    Scientific journal

  • Characteristic conformation of mosher's amide elucidated using the cambridge structural database

    Akio Ichikawa; Hiroshi Ono; Yuji Mikata

    © 2015 by the authors; licensee MDPI. Conformations of the crystalline 3,3,3-trifluoro-2-methoxy-2-phenylpropanamide derivatives (MTPA amides) deposited in the Cambridge Structural Database (CSD) were examined statistically as Racid-enantiomers. The majority of dihedral angles (48/58, ca. 83%) of the amide carbonyl groups and the trifluoromethyl groups ranged from -30° to 0° with an average angle θ1 of - 13° . The other conformational properties were also clarified: (1) one of the fluorine atoms was antiperiplanar (ap) to the amide carbonyl group, forming a staggered conformation; (2) the MTPA amides prepared from primary amines showed a Z form in amide moieties; (3) in the case of the MTPA amide prepared from a primary amine possessing secondary alkyl groups (i.e., Mosher-type MTPA amide), the dihedral angles between the methine groups and the carbonyl groups were syn and indicative of a moderate conformational flexibility; (4) the phenyl plane was inclined from the O-Cchiral bond of the methoxy moiety with an average dihedral angle θ2 of +21°; (5) the methyl group of the methoxy moiety was ap to the ipso-carbon atom of the phenyl group., 01 Jul. 2015, Molecules, 20 (7), 12880 - 12900, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Tris(8-methoxy-2-quinolylmethyl)amine (8-MeOTQA) as a highly fluorescent Zn2+ probe prepared by convenient C3-symmetric tripodal amine synthesis

    Yuji Mikata; Yuki Nodomi; Risa Ohnishi; Asako Kizu; Hideo Konno

    © The Royal Society of Chemistry 2015. A convenient synthesis of C3-symmetric tribenzylamine (TBA) derivatives has been investigated. The reaction of benzyl chlorides with acetaldehyde ammonia trimer (1) in the presence of base afforded tribenzylamines in high yields. This efficient method allows the diverse synthesis of TPA (tris(2-pyridylmethyl)amine) and TQA (tris(2-quinolylmethyl)amine) derivatives. Among the TQA compounds prepared, tris(8-methoxy-2-quinolylmethyl)amine (8-MeOTQA, 4) exhibited superior properties as a fluorescent zinc probe with high quantum yield (Zn = 0.51) and high sensitivity (limit of detection (LOD) = 3.4 nM). The X-ray crystallographic analysis of [Zn(8-MeOTQA)]2+ revealed that the steric and electronic effect of 8-methoxy substituents kicks out the solvent and counterion molecules from the metal coordination sphere, resulting in short Zn-Nquinoline coordination distances (2.04-2.07 Å). The pseudo hexacoordinate complex of 6-methoxy derivative, [Zn(6-MeOTQA)(DMF)(ClO4)]+, exhibited longer Zn-Nquinoline distances (2.07-2.19 Å) and much smaller fluorescence intensity (Zn = 0.027). The replacement of one of the three 8-methoxyquinolines with pyridine also afforded much less fluorescent zinc complex (Zn = 0.095) due to the solvent coordination (Zn-Nquinoline = 2.05-2.18 Å for [Zn(8-MeOBQPA)(CH3OH)]2+)., 07 May 2015, Dalton Transactions, 44 (17), 8021 - 8030, doi;scopus;scopus_citedby

    Scientific journal

  • TQPHEN (N,N,N′,N′-tetrakis(2-quinolylmethyl)-1,2-phenylenediamine) derivatives as highly selective fluorescent probes for Cd2+

    Yuji Mikata; Asako Kizu; Hideo Konno

    © 2015 The Royal Society of Chemistry. TQPHEN (N,N,N′,N′-tetrakis(2-quinolylmethyl)-1,2-phenylenediamine) and its methoxy-substituted derivatives, 6-MeOTQPHEN (N,N,N′,N′-tetrakis(6-methoxy-2-quinolylmethyl)-1,2-phenylenediamine) and TriMeOTQPHEN (N,N,N′,N′-tetrakis(5,6,7-trimethoxy-2-quinolylmethyl)-1,2-phenylenediamine), were examined as fluorescent Cd2+ sensors. Although the TQPHEN exhibits a negligible fluorescence response toward Zn2+ due to weak binding affinity in DMF-H2O (1:1), a 6-fold fluorescence enhancement at 392 nm was observed in the presence of 1 equiv. of Cd2+. Comprehensive X-ray crystallographic analyses of TQPHEN-Zn2+ and TQPHEN-Cd2+ complexes reveal that significant distortion in the Zn2+ complex plays a key role in the Cd2+ specificity of TQPHEN. The TriMeOTQPHEN exhibits excellent sensitivity and selectivity for Cd2+ detection (ICd/I0 = 44, ICd/IZn = 20 and LODCd = ∼10 nM (LOD = limit of detection)). On the other hand, the trans-1,2-cyclohexanediamine derivative TQDACH (N,N,N′,N′-tetrakis(2-quinolylmethyl)-trans-1,2-cyclohexanediamine) exhibits high Zn2+ specificity in the fluorescence response and extremely high Zn2+ binding affinity (Dalton Trans., 2013, 42, 9688). Subtle differences in the PHEN and DACH backbone significantly alter the stability with a specific metal and the fluorescence response of tetrakisquinoline-based fluorescent probes., 07 Jan. 2015, Dalton Transactions, 44 (1), 104 - 109, doi;scopus;scopus_citedby

    Scientific journal

  • Zinc-specific intramolecular excimer formation in TQEN derivatives: Fluorescence and zinc binding properties of TPEN-based hexadentate ligands

    Yuji Mikata; Saaya Takeuchi; Eri Higuchi; Ayaka Ochi; Hideo Konno; Kazuma Yanai; Shin Ichiro Sato

    © 2014 the Partner Organisations. Zn2+-induced fluorescence enhancement of the TPEN (N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine)-based ligand, N,N-bis(1-isoquinolylmethyl)-N′,N′-bis(pyridylmethyl)ethylenediamine (N,N-1-isoBQBPEN, 1b), has been investigated. Upon Zn2+ binding, 1b shows a fluorescence increase (Zn = 0.028) at 353 and 475 nm. The fluorescence enhancement at longer wavelengths is due to intramolecular excimer formation of two isoquinolines and is specific for Zn2+; Cd2+ induces very small fluorescence at 475 nm (ICd/IZn = 10%). The excimer formation of the [Zn(1b)]2+ complex in the excited state is supported by the time-dependent DFT calculation. Neither long-wavelength fluorescence nor excimer formation is observed in the Zn2+ complex of N,N′-1-isoBQBPEN (2b). The quinoline analog N,N-BQBPEN (1a) exhibits similar but significantly smaller excimer formation. Thermodynamic and kinetic comparisons of Zn2+ binding properties of ethylenediamine-based hexadentate ligands with pyridines and (iso)quinolines are comprehensively discussed., ROYAL SOC CHEMISTRY, 21 Nov. 2014, Dalton Transactions, 43 (43), 16377 - 16386, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Isoquinoline-derivatized tris(2-pyridylmethyl)amines as fluorescent zinc sensors with strict Zn2+/Cd2+ selectivity

    Yuji Mikata; Keiko Kawata; Saaya Takeuchi; Kaori Nakanishi; Hideo Konno; Saori Itami; Keiko Yasuda; Satoshi Tamotsu; Shawn C. Burdette

    Tris(2-pyridylmethyl)amine-based fluorescent ligands, N,N-bis(1- isoquinolylmethyl)-2-pyridylmethylamine (1-isoBQPA) and N,N-bis(7-methoxy-1- isoquinolylmethyl)-2-pyridylmethylamine (7-MeO-1-isoBQPA), have been prepared and the Zn2+-induced fluorescence enhancement has been investigated. Upon excitation at 324 nm, 1-isoBQPA exhibits a very weak emission (φ = ∼0.010) in DMF-H2O (1 : 1). Upon Zn2+ addition, the 1-isoBQPA fluorescence increases (φZn = 0.055) at 357 nm and 464 nm. The fluorescence enhancement at longer wavelengths is Zn2+- specific, whereas Cd2+ induces a small emission increase at 464 nm (ICd/I0 = 1.1, ICd/IZn = 14%). The Zn2+/Cd2+ selectivity of the fluorescent response correlates with the Cd-Nisoquinoline and Zn-Nisoquinoline bond distances measured in the crystal structures. Introduction of methoxy groups into the 1-isoBQPA chromophore enhances the fluorescence significantly (φZn = 0.213), which affords 7-MeO-1-isoBQPA properties amenable for fluorescence microscopy in living cells. © 2014 the Partner Organisations., ROYAL SOC CHEMISTRY, 28 Jul. 2014, Dalton Transactions, 43 (28), 10751 - 10759, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Bis(2-quinolylmethyl)ethylenediaminediacetic acids (BQENDAs), TQEN-EDTA hybrid molecules as fluorescent zinc sensors

    Yuji Mikata; Saaya Takeuchi; Hideo Konno; Satoshi Iwatsuki; Sakiko Akaji; Ikuko Hamagami; Masato Aoyama; Keiko Yasuda; Satoshi Tamotsu; Shawn C. Burdette

    Molecular hybrids of TQEN (N,N,N′,N′-tetrakis(2-quinolylmethyl) ethylenediamine) and EDTA (ethylenediamine-N,N,N′,N′-tetraacetic acid) were examined as fluorescent Zn2+ sensors. Upon the addition of Zn2+, N,N-BQENDA (N,N-bis(2-quinolylmethyl)ethylenediamine-N′, N′-diacetic acid, 1a) exhibits a 30-fold emission enhancement at 456 nm (λex = 315 nm, Zn = 0.018) in buffer (HEPES, pH = 7.5, 100 mM KCl). The fluorescence enhancement is Zn2+-specific as Cd2+ induces much smaller increases (ICd/I0 = 5 and ICd/IZn = 16%). These spectroscopic properties, as well as the excellent water-solubility, represent a significant improvement compared to the parent TQEN sensor (Zn = 0.007, ICd/I Zn = 64%). The isoquinoline analog N,N-1-isoBQENDA (N,N-bis(1-isoquinolylmethyl)ethylenediamine-N′,N′-diacetic acid, 1b) possesses a similar Zn2+ fluorescence response to the parent 1-isoTQEN (N,N,N′,N′-tetrakis(1-isoquinolylmethyl)ethylenediamine) sensor, but exhibits diminished fluorescence intensity. Apo 1a and 1b extract more than 50% of the Zn2+ from an equimolar amount of [Zn(TPEN)] 2+ (TPEN = N,N,N′,N′-tetrakis(2-pyridylmethyl) ethylenediamine) or [Zn(EDTA)]2-, whereas TPEN and EDTA cannot effectively remove Zn2+ from [Zn(1a)] and [Zn(1b)]. The reduction of steric crowding in [Zn(TQEN)]2+ resulting from the substitution of two quinolines with carboxylates enhances the interaction between the metal ion and the remaining quinoline nitrogen atoms. The stronger bonding interaction results in enhanced emission intensity, Zn2+ selectivity and metal ion affinity. This is in contrast to [Zn(1-isoTQEN)]2+ where the isoquinoline-carboxylate replacement does not relieve any coordination distortion, therefore no significant changes in fluorescence or metal binding properties are observed. © 2014 The Royal Society of Chemistry., ROYAL SOC CHEMISTRY, 14 Jul. 2014, Dalton Transactions, 43 (26), 10013 - 10022, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Metal Complexes of Carbohydrate-targeted Ligands in Medicinal Inorganic Chemistry

    Yuji Mikata; Michael Gottschaldt

    © 2014 John Wiley & Sons, Ltd. All rights reserved. Recent progress of ligand design in the field of medicinal inorganic chemistry includes sugar-based ligands and their metal complexes. Carbohydrate moieties are introduced to control cellular uptake, in vivo distribution and biological activities of the metal complexes. As a consequence, many carbohydrate-targeted ligands and their metal complexes play an essential part in inorganic medicinal chemistry. This chapter summarizes recent progress of carbohydrate-based ligand design for medicinal and diagnostic applications and proposes future prospects., 23 Jun. 2014, Ligand Design in Medicinal Inorganic Chemistry, 9781118488522, 145 - 173, doi;scopus;scopus_citedby

    In book

  • Quinoline-attached triazacyclononane (TACN) derivatives as fluorescent zinc sensors

    Yuji Mikata; Yuki Nodomi; Asako Kizu; Hideo Konno

    TACN (1,4,7-triazacyclononane) derivatives with three 6-methoxy-2- quinolylmethyl or 1-isoquinolylmethyl moieties were examined as fluorescent zinc sensors. Upon the addition of zinc, 6-MeOTQTACN (5) exhibited a 9-fold fluorescence increase at 420 nm (λex = 341 nm, Zn = 0.070). Fluorescence enhancement is specific for zinc and cadmium, although cadmium induces smaller increases (ICd/I0 = 3.6 and I Cd/IZn = 40%). The isoquinoline analog 1-isoTQTACN (6) exhibits minimal fluorescence enhancement upon zinc binding. TPEN (N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylene-diamine) does not extract zinc from the 6-MeOTQTACN-Zn complex (5-Zn). The quantum yield, metal ion selectivity and metal binding affinity differences between TACN and ethylenediamine (EN) skeletons in quinoline-based ligands are discussed based on the X-ray crystallographic analysis of zinc and cadmium complexes, demonstrating the superiority of quinoline-TACN conjugates. © The Royal Society of Chemistry., ROYAL SOC CHEMISTRY, 28 Jan. 2014, Dalton Transactions, 43 (4), 1684 - 1690, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • 8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl)ethylenediamine) analogs as fluorescent cadmium sensors: Strategies to enhance Cd 2+-induced fluorescence and Cd2+/Zn2+ selectivity

    Yuji Mikata; Ayaka Takekoshi; Asako Kizu; Yuki Nodomi; Masato Aoyama; Keiko Yasuda; Satoshi Tamotsu; Hideo Konno; Shawn C. Burdette

    In order to exploit the untapped sensing potential of the TQEN (N,N,N′,N′-tetrakis(2-quinolylmethyl)ethylenediamine) family of fluorescent probes, 8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl) ethylenediamine) analogs were designed and characterized. Although 8-TQEN lacks practicality owing to poor solubility in both aqueous media and organic solvents, 6-MeO-8-TQEN (N,N,N′,N′-tetrakis(6-methoxy-8- quinolylmethyl)ethylenediamine, 1b) exhibits Cd2+-selective fluorescence enhancement at 395 nm in DMF-HEPES buffer (1 : 1), (I Cd/I0 = 25, λex = 332 nm, φCd = 0.025). Zn2+ induces weaker fluorescence (I Zn/I0 = 9, IZn/ICd = 0.35). In contrast, both the parent probes TQEN (IZn/I0 = 23, I Cd/IZn = 0.64) and 6-MeOTQEN (IZn/I0 = 11, ICd/IZn = 1.29 exhibit higher sensitivity toward Zn2+. When the quinoline groups were replaced with 8-hydroxyquinoline different responses were observed. The propanediamine derivative, 8-TQOEPN (N,N,N′,N′-tetrakis(8-quinolyloxyethylene)propanediamine, 2c) exhibits significant fluorescence enhancement at 423 nm upon Cd2+ binding (λex = 325 nm, ICd/I0 = 19, φCd = 0.31). Fluorescence enhancement is Cd2+-specific as Zn2+ induces only more modest emission increases (I Zn/I0 = 8.8, IZn/ICd = 0.45). This journal is © the Partner Organisations 2014., ROYAL SOC CHEMISTRY, 2014, RSC Advances, 4 (25), 12849 - 12856, doi;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Crystal structures of Mosher's salt and ester elucidated by X-ray crystallography

    Akio Ichikawa; Hiroshi Ono; Yuji Mikata

    The crystal structure of Mosher's salt 3, prepared from (R)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid [(R)-MTPA, (R)-1] and (R)-1-phenylethylamine [(R)-PEA, (R)-2], was determined using X-ray crystallography. In crystalline salt 3, the bifurcated hydrogen bond (i.e., the methoxy-group-assisted salt bridge) and the aromatic C-H⋯π interaction formed the closest ion pair of the MTPA anion and PEA cation. The crystal packing of salt 3 was also determined. The conformations of the crystalline (Racid)-MTPA esters were then statistically examined using the Cambridge Structural Database (CSD). For secondary alcohols, ca. 65% of the dihedral angles between the ester carbonyl groups and the trifluoromethyl groups ranged between -30° and 0°. The other conformational properties associated with the trifluoromethyl, methoxy, and phenyl groups were examined in detail. The conformation of the MTPA ester prepared from the tertiary alcohol is also discussed in this paper. © 2013 The Royal Society of Chemistry., 28 Oct. 2013, CrystEngComm, 15 (40), 8088 - 8096, doi;scopus;scopus_citedby

    Scientific journal

  • Synthesis, characterization, and biological studies of emissive rhenium-glutamine conjugates

    Rachel Huang; Graeme Langille; Ravanjir K. Gill; Cindy Mei Jin Li; Yuji Mikata; May Q. Wong; Donald T. Yapp; Tim Storr

    Two new rhenium complexes containing pyridine-triazole (pyta) and quinoline-triazole (quinta) ligands with attached glutamine-targeting agents have been characterized and tested for uptake in the HT-29 human colon adenocarcinoma cell line. The glutamine moiety in Re(CO)3Br(pyta) (1) and Re(CO)3Br(quinta) (2) remains pendant in solution. Both complexes exhibit absorptions in the 300-400-nm range with metal-to-ligand charge transfer (MLCT) character, as predicted by time-dependent density functional theory calculations. Geometrical analysis by theoretical calculations provides information on the cationic complexes 1 + and 2 + resulting from aquo for halide ligand exchange under aqueous conditions. The emissive properties of both complexes were studied under aqueous conditions, and the measured quantum yields were 0.46 % for 1 + and 0.18 % for 2 +. The large Stokes shifts and oxygen sensitivity of the emission suggest a 3MLCT process for both complexes. Cell studies in the HT-29 cell line demonstrate that both complexes are nontoxic over a large concentration range (0-1.4 mM). Preliminary uptake studies show that 2 +, but not 1 +, displays significant concentration- dependent uptake at 3 and 24 h. Graphical abstract: [Figure not available: see fulltext.] © 2013 SBIC., Oct. 2013, Journal of Biological Inorganic Chemistry, 18 (7), 831 - 844, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Quantitative fluorescent detection of pyrophosphate with quinoline-ligated dinuclear zinc complexes

    Yuji Mikata; Anna Ugai; Risa Ohnishi; Hideo Konno

    Dinuclear zinc complex [Zn2(TQHPN)(AcO)]2+ exhibits characteristic fluorescence response (λex = 317 nm and λem = 455 nm) toward pyrophosphate (PPi) with maximum fluorescence upon 1:1 Zn2(TQHPN)-PPi complex formation. The crystallographic investigation utilizing P1P2-Ph 2PPi revealed that the fluorescent response mechanism is due to intramolecular excimer formation of two quinoline rings. © 2013 American Chemical Society., 16 Sep. 2013, Inorganic Chemistry, 52 (18), 10223 - 10225, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Thioether-tethered bisquinoline derivatives as fluorescent probes for mercury(ii) and iron(iii) ions

    Yuji Mikata; Fumie Nakagaki; Kaori Nakanishi

    Three ethanedithiol-linked bisquinoline derivatives with a different number of methoxy substituents on the aromatic ring exhibit a significant fluorescent response toward mercury(ii) and iron(iii) ions. Fluorescence enhancement (OFF-ON), ratiometric and fluorescence quenching (ON-OFF) responses were achieved with the same molecular skeleton, by changing the methoxy substitution pattern. © 2013 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique., Aug. 2013, New Journal of Chemistry, 37 (8), 2236 - 2240, doi;scopus;scopus_citedby

    Scientific journal

  • Quinoline-based fluorescent zinc sensors with enhanced fluorescence intensity, Zn/Cd selectivity and metal binding affinity by conformational restriction

    Yuji Mikata; Yumi Sato; Saaya Takeuchi; Yasuko Kuroda; Hideo Konno; Satoshi Iwatsuki

    Two cyclohexanediamine-based tetrakisquinoline derivatives, N,N,N′,N′-tetrakis(2-quinolylmethyl)-trans-1,2-cyclohexanediamine (TQDACH) and N,N,N′,N′-tetrakis(1-isoquinolylmethyl)-trans-1,2- cyclohexanediamine (1-isoTQDACH), have been prepared and their zinc-induced fluorescent response was investigated. In DMF-H2O (1:1) solution, TQDACH exhibits increase of fluorescence at 455 nm in the presence of 1 eq. of zinc ion (λex = 317 nm, = 0.010). Similarly, 1-isoTQDACH exhibited fluorescence enhancement upon binding with zinc (λex = 325 nm, λem = 352 and 475 nm, = 0.032). The fluorescence intensity ratio induced by cadmium relative to zinc (ICd/I Zn) for these 1,2-cyclohexanediamine probes is lower than those for the corresponding ethylenediamine derivatives, TQEN and 1-isoTQEN. Crystal structures of the zinc and cadmium complexes of TQDACH and 1-isoTQDACH reveal the superior metal binding ability of the 1,2-cyclohexanediamine and isoquinoline moieties in comparison to ethylenediamine and quinoline. The conformational restriction afforded by the 1,2-cyclohexanediamine skeleton upon zinc binding leads to enhanced fluorescence intensity and strong metal binding affinity. © The Royal Society of Chemistry 2013., 14 Jul. 2013, Dalton Transactions, 42 (26), 9688 - 9698, doi;scopus;scopus_citedby

    Scientific journal

  • Synthesis, crystal structure, and electronic absorption of chlorophyll derivatives possessing a β-diketonate moiety at the C3 position

    Yusuke Kinoshita; Michio Kunieda; Yuji Mikata; Hitoshi Tamiaki

    A chlorophyll-a derivative possessing a trifluoroacetylacetonate moiety at the C3 position was prepared by Claisen condensation of the 3-acetyl group with ethyl trifluoroacetate in the presence of sodium methoxide. The Claisen condensation was successfully applied for the reaction of 3-acetyl-chlorin with ethyl pentafluoropropionate as well as that of 3-acetyl-bacteriochlorin with ethyl trifluoroacetate. The resulting Claisen condensation products took exclusively diketonate conformers in a CDCl3 solution and the single crystal, and gave red-shifted and broadened Qx/Qy absorption bands in the visible to near-infrared region, compared with the corresponding 3-acetyl-(bacterio)chlorins. © 2013 Elsevier Ltd. All rights reserved., 06 Mar. 2013, Tetrahedron Letters, 54 (10), 1243 - 1246, doi;scopus;scopus_citedby

    Scientific journal

  • Heterocyclic bismuth carboxylates based on a diphenyl sulfone scaffold: Synthesis and antifungal activity against Saccharomyces cerevisiae

    Toshihiro Murafuji; Kunito Kitagawa; Daisuke Yoshimatsu; Kei Kondo; Katsuya Ishiguro; Ryo Tsunashima; Isamu Miyakawa; Yuji Mikata

    A series of heterocyclic organobismuth(III) carboxylates 4 and 5 [RCO 2Bi(C6H4-2-SO2C6H 4-1′-)] derived from diphenyl sulfone was synthesized to determine the influence of the carboxylate ligand structure on the lipophilicity and antifungal activity against the yeast Saccharomyces cerevisiae. In contrast to the clear structure-activity relationship between the size of the inhibition zone and the value of ClogP for specific substitution on diphenyl sulfone scaffold 1 [ClBi(5-RC6H3-2-SO2C 6H4-1′-)], scaffolds 4 and 5 showed similar inhibition activities irrespective of the ClogP value. This suggests that these molecules function inside the yeast cell by separating into the cationic heterocyclic bismuth scaffold and the anionic carboxylate moiety, and that the bismuth scaffold plays an important role in the inhibition activity. © 2013 Elsevier Masson SAS. All rights reserved., 2013, European Journal of Medicinal Chemistry, 63, 531 - 535, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis and photodynamic properties of maltohexaose-conjugated porphyrins

    Yuji Mikata; Minako Shibata; Yasuko Baba; Toyoji Kakuchi; Misaki Nakai; Shigenobu Yano

    A series of porphyrin derivatives with one to four maltohexaose moieties in their meso positions have been synthesized. Zinc or free-base m-THPP (5,10,15,20-tetrakis(m-hydroxyphenyl)-porphyrin) was used as the porphyrin platform. The reaction of m-THPP with 3-iodopropyl nonadecaacetylmaltohexaoside afforded a mixture of all possible combinations of glycoconjugated porphyrins having one to four maltohexaose moieties; monoglycosylated (Ac-1), bisglycosylated (Ac-cis-2 and Ac-trans-2), triglycosylated (Ac-3), and tetraglycosylated (Ac-4) porphyrins were obtained in 1126% yield. Removal of acetyl groups at maltohexaose moiety afforded highly water-soluble glycoconjugated porphyrins 14. Zinc derivatives were synthesized in a similar manner. These maltohexaose-linked porphyrins exhibit remarkable water-solublity (530 mg/mL for 4). The singlet oxygen production ability upon visible light irradiation is not affected by the maltohexaose substitution. Photo- and dark cytotoxicities of the maltohexaose-conjugated porphyrins 14 and Zn-14 were examined against a HeLa cell line, which showed that the mono-maltohexaosylated derivative (1 and Zn-1) was the most effective photosensitizer for PDT. © 2012 World Scientific Publishing Company., Nov. 2012, Journal of Porphyrins and Phthalocyanines, 16 (11), 1177 - 1185, doi;scopus;scopus_citedby

    Scientific journal

  • Naphthyl groups in chiral recognition: Structures of salts and esters of 2-methoxy-2-naphthylpropanoic acids

    Akio Ichikawa; Hiroshi Ono; Yuji Mikata

    The crystal structures of salt 8, which was prepared from (R)-2-methoxy-2-(2-naphthyl)propanoic acid ((R)-MβNP acid, (R)-2) and (R)-1-phenylethylamine ((R)-PEA, (R)-6), and salt 9, which was prepared from (R)-2-methoxy-2-(1-naphthyl)propanoic acid ((R)-MαNP acid, (R)-1) and (R)-1-(p-tolyl)ethylamine ((R)-TEA, (R)-7), were determined by X-ray crystallography. The MβNP and MαNP anions formed ion-pairs with the PEA and TEA cations, respectively, through a methoxy-group-assisted salt bridge and aromatic CH⋯π interactions. The networks of salt bridges formed 2 1 columns in both salts. Finally, (S)-(2E,6E)-(1- 2H 1)farnesol ((S)-13) was prepared from the reaction of (2E,6E)-farnesal (11) with deuterated (R)-BINAL-H (i.e., (R)-BINAL-D). The enantiomeric excess of compound (S)-13 was determined by NMR analysis of (S)-MαNP ester 14. The solution-state structures of MαNP esters that were prepared from primary alcohols were also elucidated. Princess and the PEA: The crystal structures of the MαNP and MβNP salts were determined by X-ray crystallography. The 1-naphthyl group of the MαNP anion and the 2-naphthyl group of the MβNP anion acted as a C-H donor and -acceptor, respectively. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., Oct. 2012, Chemistry - An Asian Journal, 7 (10), 2294 - 2304, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Syntheses, characterization, and antitumor activities of platinum(II) and palladium(II) complexes with sugar-conjugated triazole ligands

    Shigenobu Yano; Hiromi Ohi; Mizue Ashizaki; Makoto Obata; Yuji Mikata; Rika Tanaka; Takanori Nishioka; Isamu Kinoshita; Yuko Sugai; Ichiro Okura; Shun Ichiro Ogura; Justyna A. Czaplewska; Michael Gottschaldt; Ulrich S. Schubert; Takuzo Funabiki; Keiko Morimoto; Misaki Nakai

    Four platinum(II) and palladium(II) complexes with sugar-conjugated bipyridine-type triazole ligands, [PtIICl2(AcGlc-pyta)] (3), [PdIICl2(AcGlc-pyta)] (4), [PtIICl 2(Glc-pyta)] (5), and [PdIICl2(Glc-pyta)] (6), were prepared and characterized by mass spectrometry, elemental analysis, 1H- and 13C-NMR, IR as well as UV/VIS spectroscopy, where AcGlc-pyta and Glc-pyta denote 2-[4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl]ethyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside (1) and 2-[4-(pyridin-2-yl)-1H- 1,2,3-triazol-1-yl]ethyl β-D-glucopyranoside (2), respectively. The solid-state structure of complex 6 was determined by single-crystal X-ray-diffraction analysis. These complexes exhibited in vitro cytotoxicity against human cervix tumor cells (HeLa) though weaker than that of cisplatin. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich., Sep. 2012, Chemistry and Biodiversity, 9 (9), 1903 - 1915, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Quinoline-based, glucose-pendant fluorescent zinc probes

    Yuji Mikata; Anna Ugai; Keiko Yasuda; Saori Itami; Satoshi Tamotsu; Hideo Konno; Satoshi Iwatsuki

    Quinoline-based tetradentate ligands with glucose pendants, N,N'-bis[2-(β-d-glucopyranosyloxy)ethyl]-N,N'-bis[(6-methoxyquinolin-2-yl) methyl]ethylenediamine (N,N'-6-MeOBQBGEN) and its N,N-counterpart, N,N-6-MeOBQBGEN, have been prepared, and their fluorescence-spectral changes upon Zn binding were investigated. Upon excitation at 336 nm, N,N'-6-MeOBQBGEN showed weak fluorescence (φ≈ 0.016) in HEPES buffer (HEPES 50 mM, KCl 100 mM, pH 7.5). In the presence of Zn, N,N'-6-MeOBQBGEN exhibited a significant increase in fluorescence (φ=0.096) at 414 nm. The fluorescence enhancement is specific for Zn and Cd (ICd/IZn of 50% at 414 nm). On the other hand, N,N-6-MeOBQBGEN exhibited a smaller fluorescence enhancement upon Zn complexation (φ=0.043, λex=334 nm, λem=407 nm) compared with N,N'-6-MeOBQBGEN. Fluorescence microscopic analysis using PC-12 rat adrenal cells revealed that N,N'-6-MeOBQBGEN exhibits a 1.8-fold higher fluorescence-signal response to Zn ion concentration compared with sugar-depleted compound 2 (N,N'-bis[(6- methoxyquinolin-2-yl)methyl]ethylenediamine), due to its enhanced uptake into cells due to the targeting ability of the attached carbohydrates. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich., Sep. 2012, Chemistry and Biodiversity, 9 (9), 2064 - 2075, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Differentiation of oxygen atom chirality in copper(II) complexes with dipicolylamine-derived ligands

    Yuji Mikata; Tomomi Fujimoto; Noko Imai; Shin Ichi Kondo

    The ether coordination of the oxygen atom to the copper(II) center supported by dipicolylamine (DPA)-derived ligands,N-[2-(2-pyridylmethyloxy) ethyl]-N,N-bis(2-pyridylmethyl)amine (L Py), N-[2-(2- quinolylmethyloxy)ethyl]-N,N-bis(2-pyridylmethyl)amine (L Q), N-[3-(2-pyridylmethyloxy)-1-propyl]-N,N-bis(2-pyridylmethyl)amine (L' Py), N-{2-[1-(2-pyridyl)ethyloxy]ethyl}-N,N-bis(2-pyridylmethyl)amine (L Py* 1), N-[2-(2-pyridylmethyloxy)-1-propyl]-N,N- bis(2-pyridylmethyl)amine (L Py* 2), and N-[2-(carboxymethyloxy)ethyl]-N,N-bis(2-pyridylmethyl)amine (HL COO), have been examined. The factors that facilitate the coordination of the ether oxygen atom of these ligands to the copper center and the control of chirality around the copper-coordinated oxygen atom are discussed. The copper center exhibits a pentacoordinate geometry with these ligands, as evidenced by X-ray crystallography. The steric effect of the quinoline ring in the L Q complex prevents the coordination of a perchlorate anion to the copper center, which affords the pentacoordinate divalent complex with a shorter copper-oxygen bond than that for the corresponding pyridine ligand (L Py). The six-membered chelate in the L' Py complex also exhibits a shorter Cu-O distance. The conformation of the oxygen atom of the L Py complex is unstable because of fast lone pair inversion, but this inversion is prevented for the complexes with chiral ligands, L Py* 1 and L Py* 2. Upon chelation to the metal center, the HL COO ligand forms a pentacoodinate monomer complex that further affords a 1-D polymer structure. With respect to the oxygen chirality, the water content of the solvent governs the formation of either a homochiral polymer (R-R-R-R- or S-S-S-S-) or an alternative chirality polymer (R-S-R-S-). In this case, the isomers with respect to the oxygen chirality were separated and characterized. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., Sep. 2012, European Journal of Inorganic Chemistry, (27), 4310 - 4317, doi;scopus;scopus_citedby

    Scientific journal

  • Photooxidative cleavage of zinc 20-substituted chlorophyll derivatives: Conformationally P-helix-favored formation of regioselectively 19-20 opened linear tetrapyrroles

    Hitoshi Tamiaki; Yukihiro Okamoto; Yuji Mikata; Sunao Shoji

    © The Royal Society of Chemistry and Owner Societies 2012. Photoreaction of zinc methyl 20-substituted meso(pyro)pheophorbide-a prepared by modifying naturally occurring chlorophyll-a in the presence of oxygen molecules gave its C19-C20 oxidative cleavage (1-carbonyl-19-oxo-bilatrienes) as the major products and the regioisomeric C1-C20 cleavage (19-carbonyl-1-oxo-bilatrienes) as the minor products. The resulting zinc complexes of linear tetrapyrroles took a helical conformation and the P-conformers were preferential over the M-stereoisomers due to the presence of their 17S,18S-chiral centers. The helical conformers (diastereomers) of the corresponding nickel complexes were separated by reverse-phase or chiral HPLC and their conformational changes were observed in solution., 01 Jun. 2012, Photochemical and Photobiological Sciences, 11 (6), 898 - 907, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Zinc-specific fluorescent response of tris(isoquinolylmethyl)amines (isoTQAs)

    Yuji Mikata; Keiko Kawata; Satoshi Iwatsuki; Hideo Konno

    Isoquinoline-based tetradentate ligands with C 3-symmetry, tris(1- or 3-isoquinolylmethyl)amine (1- or 3-isoTQA), have been prepared and their zinc-induced fluorescence enhancement was investigated. Upon excitation at 324 nm, 1-isoTQA shows very weak fluorescence (β = ∼0.003) in DMF/H 2O (1/1) solution. In the presence of zinc ion, 1-isoTQA exhibits fluorescence increase (β = 0.041) at 359 and 470 nm. This fluorescence enhancement at 470 nm is specific for zinc. However, 3-isoTQA exhibited a smaller fluorescence enhancement upon zinc complexation (β = 0.017, λ em = 360 and 464 nm) compared with 1-isoTQA. Crystal structures of zinc complexes of isoTQAs demonstrate the diminished steric crowding and shorter Zn-N aromatic distances compared with isoTQENs (N,N,N′,N′-tetrakis(isoquinolylmethyl)ethylenediamines) leads to a higher fluorescent response toward zinc relative to cadmium. © 2012 American Chemical Society., 06 Feb. 2012, Inorganic Chemistry, 51 (3), 1859 - 1865, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Development of sugar-based materials for biological devices

    Yuji Mikata; Shigenobu Yano

    Recent progresses of our group dealing with newly developed sugar-based ligands and their metal complexes have been reviewed. Carbohydrate moiety affects on the stereochemistry around the metal center and controls the biological activity of the complex. © 2012 Bentham Science Publishers., Feb. 2012, Current Topics in Medicinal Chemistry, 12 (3), 145 - 157, doi;pubmed;scopus;scopus_citedby

  • Synthesis of rhenium(I) tricarbonyl complexes with carbohydrate-pendant tridentate ligands and their cellular uptake

    Yuji Mikata; Kyoko Takahashi; Yuka Noguchi; Masami Naemura; Anna Ugai; Saori Itami; Keiko Yasuda; Satoshi Tamotsu; Takashi Matsuo; Tim Storr

    Twelve [Re IL(CO) 3] n+ complexes with various carbohydrate-pendant ligands L have been prepared and their uptake into HeLa S3 cells were investigated. The ligand library includes: (i) glucose/galactose as the carbohydrate group; (ii) bis(2-pyridylmethyl)amine (DPA), bis(2-quinolylmethyl)amine (DQA), or N-(2-pyridylmethyl)glycine (NPG) as the metal binding component; and (iii) an ethylene chain as a linker between the metal binding site and the O/C-glycosides. Microwave induced plasma mass spectroscopy (MIP-MS) measurements revealed that all complexes were extensively incorporated into the HeLa cells over a 24 h period, and the DQA complexes showed the highest uptake of all the complexes in the series. However, in comparison to the corresponding Re complexes without the pendant carbohydrate functions (prepared with the related ligands L DPA, L DQA, and L NPG), only the NPG complexes exhibited carbohydrate enhanced cellular uptake. Considering their water solubility and cellular uptake properties, the NPG complexes containing an O-glycoside group (L1 and L′1) are the best candidates for enhancing cellular uptake of metal ions. Microscopic analysis with PC-12 cells in the presence of thefluorescent complex [Re(L′7)(CO) 3]Cl, revealed that the complex stays in the cell cytosol and cannot penetrate into the nucleus. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., Jan. 2012, European Journal of Inorganic Chemistry, (2), 217 - 225, doi;scopus;scopus_citedby

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  • Triphenylphosphine-mediated reaction of dialkyl azodicarboxylate with activated alkenes leading to pyrazolines

    Shoko Yamazaki; Yuta Maenaka; Ken Fujinami; Yuji Mikata

    Reaction of the Huisgen zwitterions, derived from triphenylphosphine and azodicarboxylates with activated alkenes has been studied. The reaction of various ethenetricarboxylates and diethyl azodicarboxylate with PPh3 gave pyrazolines efficiently. This pyrazoline synthesis is also applicable to 2-substituted acrylates such as trimethyl 2-phosphonoacrylate and methyl 2-(trifluoromethyl)acrylate. The possible reaction mechanism was discussed in comparison with the reaction of acetylenedicarboxylate and Huisgen zwitterions. The selective transformation of pyrazoline products have also been performed.© 2012 The Royal Society of Chemistry., 2012, RSC Advances, 2 (21), 8095 - 8103, doi;scopus;scopus_citedby

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  • Crystal structures and chiral recognition of the diastereomeric salts prepared from 2-methoxy-2-(1-naphthyl)propanoic acid

    Akio Ichikawa; Hiroshi Ono; Takuya Echigo; Yuji Mikata

    This paper is the first to report the structures of crystalline diastereomeric salts 8 and 9 prepared from (R)-2-methoxy-2-(1-naphthyl)propanoic acid [(R)-MαNP acid, (R)-1] and (S)-1 with (R)-1-phenylethylamine [(R)-PEA, (R)-7], respectively. These crystal structures helped elucidate a novel chiral recognition mechanism characteristic of MαNP salts. The less-soluble diastereomeric salt 8 prepared from (R)-1 and (R)-7 formed an ammonium-carboxylate ion pair by means of a methoxy-assisted salt bridge and an aromatic CH⋯π interaction. The more-soluble diastereomeric salt 9 prepared from (S)-1 and (R)-7 formed an ion pair by a methoxy-assisted salt bridge in which the 1-naphthyl and phenyl groups did not overlap. Instead, salt 9 formed a close ion pair by means of a salt bridge, a CH⋯O hydrogen bond, and a π⋯π interaction. These crystal structures suggest that the molecular length from the MαNP plane containing the carboxy and methoxy groups is critical to the crystallisation of diastereomeric salts. The crystal packing in both salts was investigated with regard to the weak interactions (i.e., salt bridges, NH⋯O and CH⋯O hydrogen bonds, and aromatic CH⋯π, CH⋯π, and π⋯π interactions). Finally, diastereomeric amides 11 and 12 were prepared from (S)-2-methoxy-2-(2-naphthyl)propanoic acid [(S)-MβNP acid, (S)-2] and (R)-2 with (S)-1-(1-naphthyl)ethylamine [(S)-10]. The solution-phase structures of the MβNP amides, and their separation, was investigated by NMR spectroscopy and high-performance liquid chromatography (HPLC). The less-stereochemically demanding and longer 2-naphthyl group made the MβNP amide more flexible and less polar than the MαNP amide. Acid 2 was more efficient than acid 1 in separating amides 11 and 12. © The Royal Society of Chemistry 2011., ROYAL SOC CHEMISTRY, 21 Jul. 2011, CrystEngComm, 13 (14), 4536 - 4548, doi;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Intramolecular ether oxygen coordination in the zinc complexes with dipicolylamine (DPA)-derived ligands

    Yuji Mikata; Tomomi Fujimoto; Tomomi Fujiwara; Shin Ichi Kondo

    The ether oxygen coordination to the zinc center in the complexes with dipicolylamine (DPA)-derived ligands, N-(2-methoxyethyl)-N,N-bis(2- pyridylmethyl)amine (L), N-(3-methoxypropyl)-N,N-bis(2-pyridylmethyl)amine (L′), and N-{3-(2-pyridylmethyloxy)propyl}-N,N-bis(2-pyridylmethyl)amine (LPy) has been discussed. Upon chelation of the oxygen atom, L forms a five-membered chelate ring with respect to the 2-aminoethyl ether moiety whereas L′ forms a six-membered chelate in 3-aminopropyl ether unit. This difference was highlighted by the crystal structures of ZnCl2 complexes, in which [Zn(L)Cl2] (1) exhibited ether oxygen coordination but [Zn(L′)Cl2] (2) had the ether oxygen non-coordinated. The terminal pyridyl group of LPy facilitates the ether oxygen atom coordination via a metal binding from the basal plane trans to the aliphatic nitrogen. © 2011 Elsevier Ltd. All rights reserved., ELSEVIER SCIENCE SA, 15 May 2011, Inorganica Chimica Acta, 370 (1), 420 - 426, doi;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Methoxyquinoline-diethylenetriamine conjugate as a fluorescent zinc sensor

    Yuji Mikata; Azusa Yamashita; Keiko Kawata; Hideo Konno; Saori Itami; Keiko Yasuda; Satoshi Tamotsu

    A 6-methoxyquinoline conjugated diethylenetriamine derivative, N,N′′-bis(6-methoxy-2-quinolylmethyl)diethylenetriamine (6-MeOBQDIEN) has been synthesized and its fluorescent response toward zinc ion was investigated. In the presence of zinc ion, 6-MeOBQDIEN exhibits fluorescence (λex = 329 nm, λem = 418 nm, = 0.039). The fluorescent intensity of the zinc complex of the compound is two times higher than the parent BQDIEN ( = 0.021) under the same conditions. The crystal structure of 6-MeOBQDIEN-Zn complex shows that all five nitrogen atoms participate to the metal coordination in a distorted square-pyramidal geometry (τ = 0.145) with the aliphatic nitrogen in an apical position. Fluorescent microscopic analysis using 6-MeOBQDIEN reveals the zinc ion concentration change in living cells. © 2011 The Royal Society of Chemistry., ROYAL SOC CHEMISTRY, 14 May 2011, Dalton Transactions, 40 (18), 4976 - 4981, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Methoxy-substituted isoTQEN family for enhanced fluorescence response toward zinc ion

    Yuji Mikata; Azusa Yamashita; Keiko Kawata; Hideo Konno; Saori Itami; Keiko Yasuda; Satoshi Tamotsu

    Previously, we have reported that 1- and 3-isoTQENs (N,N,N′,N′- tetrakis(1- or 3-isoquinolylmethyl)ethylenediamines) exhibit a specific fluorescence enhancement toward zinc ion. In this study, three methoxy-substituted derivatives of 1-isoTQEN were synthesized and their fluorescent response toward zinc ion was studied. The substitution pattern of the methoxy group significantly changes the solubility of compounds in aqueous DMF, λmax in the absorption spectra, excitation/emission wavelengths and fluorescence intensity of zinc complexes. In the presence of zinc ion, 7-MeO-1-isoTQEN exhibits higher fluorescence intensity and longer excitation/emission wavelengths (λex = 342 nm, λem = 526 nm) than 6-MeO-1-isoTQEN (λex = 303 nm, λem = 469 nm) and 5,6,7-triMeO-1-isoTQEN (λex = 340 nm, λem = 504 nm). The fluorescence intensity of a zinc complex of 7-MeO-1-isoTQEN ( = 0.122) is four times higher than the parent 1-isoTQEN ( = 0.034) under the same conditions. The crystal structure of 7-MeO-1-isoTQEN-Zn complex reveals that all six nitrogen atoms participate to the metal coordination with ideal octahedral geometry, affording significantly high metal binding affinity comparable with TPEN (N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine). 7-MeO-1-isoTQEN detects zinc ion concentration change in cells by fluorescence microscopic analysis. © 2011 The Royal Society of Chemistry., ROYAL SOC CHEMISTRY, Apr. 2011, Dalton Transactions, 40 (16), 4059 - 4066, True, doi;pubmed;web_of_science;scopus;scopus_citedby

    Scientific journal

  • Bismuth heterocycles based on a diphenyl sulfone scaffold: Synthesis and substituent effect on the antifungal activity against Saccharomyces cerevisiae

    Toshihiro Murafuji; Yudai Fujiwara; Daisuke Yoshimatsu; Isamu Miyakawa; Kouto Migita; Yuji Mikata

    A series of heterocyclic organobismuth(III) compounds 2 [ClBi(5-R-C 6H 3-2-SO 2C 6H 4-1'-): R = Me, Ph, MeO, Cl, H, t-Bu, CF 3, F, Me 2N] was synthesized in order to study the relative importance of structure and specific substitutions in relation to their lipophilicity and antifungal activity against the yeast Saccharomyces cerevisiae. A clear structure-activity relationship between the size of the inhibition zone and the value of ClogP was found for 2. These results suggest that the higher the lipophilicity, the lower the antifungal activity. Thus, 2e (R = H) and 2h (R = F), which had ClogP values of 1.18 and 1.45, respectively, were most active. In contrast, 2b (R = Ph) and 2f (R = t-Bu) had ClogP values of 3.06 and 3.00, respectively, and exhibited no antifungal activity. Compound 6b ClBi[5-(OH)C 6H 3-2-SO 2-5′-(OH)C 6H 3-1'-] had an estimated ClogP value of 0.81 but exhibited only low activity in spite of its low ClogP value, suggesting that such a considerable decrease in lipophilicity lowers inhibition activity. Bismuth carboxylate 7b derived from p-nitrobenzoic acid and 2e exhibited inhibition activity comparable to those of 2e and 2h despite its higher lipophilicity (ClogP = 2.68). © 2010 Elsevier Masson SAS. All rights reserved., ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER, Feb. 2011, European Journal of Medicinal Chemistry, 46 (2), 519 - 525, doi;web_of_science;pubmed;scopus;scopus_citedby

    Scientific journal

  • Antifungal bismuth heterocycles based on diphenyl sulfone scaffold

    T. Murafuji; Y. Fujiwara; D. Yoshimatsu; K. Migita; I. Miyakawa; Y. Mikata

    2011, Eur. J. Med. Chem., 46, 519 - 525, doi

    Scientific journal

  • Lewis acid promoted reactions of ethenetricarboxylates with allenes: Synthesis of indenes and γ-lactones via conjugate addition/cyclization reaction

    Shoko Yamazaki; Yuko Yamamoto; Yugo Fukushima; Masachika Takebayashi; Tetsuma Ukai; Yuji Mikata

    (Figure presented) Indenes are important core structures in organic chemistry. Few simple arylallenes have been used to construct indene skeletons by Friedel-Crafts reaction. Lewis acid catalyzed reaction of ethenetricarboxylates 1 and arylallenes has been examined in this study. The reaction of arylallenes and ethenetricarboxylate triesters with SnCl 4 gave indene derivatives efficiently, via a conjugate addition/Friedel-Crafts cyclization reaction. On the other hand, the reactions of 1,1-diethyl 2-hydrogen ethenetricarboxylate and arylallenes or alkylallenes with SnCl 4 at -78 °C or room temperature and subsequent treatment with Et 3N gave γ-lactones. The reactions of triethyl ethenetricarboxylate and 1,1-dialkylallenes with SnCl 4 at room temperature also gave γ-lactones. © 2010 American Chemical Society., 06 Aug. 2010, Journal of Organic Chemistry, 75 (15), 5216 - 5222, doi;pubmed;scopus;scopus_citedby

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  • Crystal conformations and molecular packing of (S)-2-methoxy-2-(9- phenanthryl)propanoic acid and a diastereomeric amide prepared from (R)-2-methoxy-2-(1-naphthyl)propanoic acid

    Akio Ichikawa; Hiroshi Ono; Makiko Takenaka; Yuji Mikata

    This paper reports the first evidence of the contribution of T-shaped aromatic CH⋯π interactions to the crystallization of 2-aryl-2-methoxypropanoic acid and amide. The crystal structures of (S)-2-methoxy-2-(9-phenanthryl)propanoic acid [(S)-M9PP acid, (S)-3] and a diastereomeric amide 6, prepared from (R)-2-methoxy-2-(1-naphthyl)propanoic acid [(R)-MαNP acid, (R)-1] and (S)-1-(1-naphthyl)ethylamine [(S)-4], were determined by X-ray crystallography. Like those of M9PP and MαNP esters, the carbonyl and methoxy groups of (S)-3 exhibited syn conformation. The crystal structure of (S)-3 was stabilized by consecutive intermolecular OH⋯O hydrogen bonds between the carboxy groups. In addition, the 9-phenanthryl groups formed a herringbone structure via aromatic CH⋯ π interactions. The anti conformation of the carbonyl and methoxy groups was observed in the crystal of amide 6, indicating an NH⋯O hydrogen bond. The two 1-naphthyl groups were parallel to one another and located on the same side of the MαNP plane, forming a herringbone structure with adjacent molecules. NMR analyses suggest that, in solution, intramolecular aromatic CH⋯π interactions induce the 1-naphthyl groups to form a slant-parallel conformation. Namely, both the length and interactions between the substituents are important for crystallization. Normal-phase HPLC separation of diastereomeric amides is also discussed. © 2010 The Royal Society of Chemistry., Jul. 2010, CrystEngComm, 12 (7), 2261 - 2268, doi;scopus;scopus_citedby

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  • Cationic technetium and rhenium complexes with pendant carbohydrates

    Cara L. Ferreira; Fabio L.N. Marques; Miriam R.Y. Okamoto; Andréia H. Otake; Yuko Sugai; Yuji Mikata; Tim Storr; Meryn Bowen; Shigenobu Yano; Michael J. Adam; Roger Chammas; Chris Orvig

    Three carbohydrate conjugated dipicolylamine chelators, 2-bis(2-pyridinylmethyl)amino)ethyl 1-deoxy-1-thio-β-D-glucopyranoside (L1), 2-bis(2-pyridinylmethyl)amino)ethyl-β-D-glucopyranoside (L2), and 2-bis(2-pyridinylmethyl)amino)carboxamide-N-(2-amino-2-deoxy-D-glucopyra nose) (L3) were complexed to the [M(CO)3]+ core (M=Tc, Re) and the properties of the resulting complexes were investigated. Synthesis and characterization of the chelator 2-bis(2-pyridinylmethyl)amino)ethyl 1-deoxy-1-thio-β-D-glucopyranoside (L1) and the corresponding Re complex are reported. All chelators were radiolabeled in high yield with [99mTc(CO)3(H2O)3] + (>98%) and [186Re(CO)3(H2O)3] + (>80%). The chelators and Re-complexes were determined to not be substrates for the glucose metabolism enzyme hexokinase. However, the biodistribution of each of the 99mTc complexes demonstrated fast clearance from most background tissue, including >75% clearance of the activity in the kidneys and the liver within 2 h post-injection. © 2010 Elsevier Ltd. All rights reserved., Jun. 2010, Applied Radiation and Isotopes, 68 (6), 1087 - 1093, doi;pubmed;scopus;scopus_citedby

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  • Cationic technetium and rhenium complexes with pendant carbohydrates

    Cara L. Ferreira; Fabio L. N. Marques; Miriam R. Y. Okamoto; Andreia H. Otake; Yuko Sugai; Yuji Mikata; Tim Storr; Meryn Bowen; Shigenobu Yano; Michael J. Adam; Roger Chammas; Chris Orvig

    Three carbohydrate conjugated dipicolylamine chelators, 2-bis(2-pyridinylmethyl)amino)ethyl 1-deoxy-1-thio-beta-D-glucopyranoside (L(1)), 2-bis(2-pyridinylmethyl)amino)ethyl-beta-D-glucopyranoside (L(2)), and 2-bis(2-pyridinylmethyl)amino)carboxamide-N-(2-amino-2-deoxy-D-glucopyranose) (L(3)) were complexed to the [M(Co)(3)](+) core (M=Tc, Re) and the properties of the resulting complexes were investigated. Synthesis and characterization of the chelator 2-bis(2-pyridinylmethyl)amino)ethyl 1-deoxy-1-thio-beta-D-glucopyranoside (L(1)) and the corresponding Re complex are reported. All chelators were radiolabeled in high yield with [(99)mTc(CO)(3)(H(2)O)(3)](+) ( > 98%) and [(186)Re(CO)(3)(H(2)O)(3)](+) ( > 80%). The chelators and Re-complexes were determined to not be substrates for the glucose metabolism enzyme hexokinase. However, the biodistribution of each of the (99m)Tc complexes demonstrated fast clearance from most background tissue, including >75% clearance of the activity in the kidneys and the liver within 2 h post-injection. (C) 2010 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD, Jun. 2010, APPLIED RADIATION AND ISOTOPES, 68 (6), 1087 - 1093, doi;web_of_science

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  • Control of the aggregation properties of Tris(maltohexaose)-linked porphyrins with an alkyl chain

    Yuji Mikata; Taichi Sawaguchi; Toyoji Kakuchi; Michael Gottschaldt; Ulrich S. Schubert; Hiromi Ohi; Shigenobu Yano

    A series of porphyrins with three maltohexaose units and one alkyl chain (ethyl, butyl, hexyl, decyl, and hexadecyl) has been synthesized. Aggregation properties were investigated by absorbance and circular dichroism (CD) spectra. These trismaltohexaosylated tetraphenylporphyrins exhibited high water solubility. Although these porphyrins exhibited sharp Soret bands in DMSO solution, the Soret band broadened in a concentration-dependent manner in aqueous solution. This is the result of the aggregation of porphyrin molecules in aqueous solution. Interestingly, trismaltohexaosylated porphyrins with long alkyl chains of a certain length exhibited a broad. Soret band in water without concentration dependency due to the stability of such, aggregates. The CD spectra were silent in DMSO solution in all porphyrin derivatives, indicating that the maltohexaose moiety does not interact with the porphyrin chromophore in the monomelic state. However, in water, a splitting Cotton effect was observed at the Soret band. Intensity of this CD signal decreased as the length of the alkyl chain was extended. These observations show the formation of a chiral, face-to-face aggregate, in which the porphyrin rings are in close proximity to each other for short; alkyl chain derivatives. The porphyrin derivatives with long alkyl chains exhibit edge-to-edge aggregation, where hydrophobic interaction of the alkyl chains separates the porphyrin chromophores. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA., 2010, European Journal of Organic Chemistry, (4), 663 - 671, doi;scopus;scopus_citedby

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  • Antioxidant action of sugar-pendant C60 fullerenes

    Masanori Horie; Akiko Fukuhara; Yoshiro Saito; Yasukazu Yoshida; Hiroe Sato; Hiromi Ohi; Makoto Obata; Yuji Mikata; Shigenobu Yano; Etsuo Niki

    The action of C60 fullerene and its derivatives as a radical-scavenging antioxidant has received much attention, but their reactivity toward free radicals and antioxidant capacity have not been well elucidated yet. In the present study, the reactivity of the two types of water-soluble, sugar-pendant C60 fullerenes, C60-1S and C60-2S, toward peroxyl radical and their effect against human plasma lipid peroxidation were measured. The rate constants for the reaction of C60-1S and C60-2S with peroxyl radicals were obtained from their effect on the bleaching of β-carotene in lipid-SDS micelle system as 4.6 × 103 and 8.0 × 103 M-1 s-1 at 37 °C, respectively. They inhibited the free radical-induced lipid peroxidation in human plasma in a concentration-dependent manner. These results suggest that the sugar-pendant fullerenes C60-1S and C60-2S act as a radical-scavenging antioxidant with the activity similar to the phenolic antioxidants. © 2009 Elsevier Ltd. All rights reserved., 15 Oct. 2009, Bioorganic and Medicinal Chemistry Letters, 19 (20), 5902 - 5904, doi;pubmed;scopus;scopus_citedby

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  • Zinc-catalyzed reactions of ethenetricarboxylates with 2- (trimethylsilylethynyl)anilines leading to bridged quinoline derivatives

    Shoko Yamazaki; Satoshi Morikawa; Kazuya Miyazaki; Masachika Takebayashi; Yuko Yamamoto; Tsumoru Morimoto; Kiyomi Kakiuchi; Yuji Mikata

    Zinc Lewis acid-catalyzed cyclization of thenetricarboxylate derivatives 1 with 2-ethynylanilines has been examined. Reaction of 1,1-diethyl 2-fert-butyl ethenetricarboxylate 1 b with 2-(trimethylsilylethynyl)aniline substrates In the presence of Zn(OTf)2 gave bridged quinoline derivatives In 43-85% yield. The reaction of 1b with 2′-aminoacetophenone also gave the bridged quinoline derivative In 41% yield. Thermal reaction of bridged quinolines (180-190 °C) afforded indole derivatives in moderate to good yields. © 2009 American Chemical Society., 02 Jul. 2009, Organic Letters, 11 (13), 2796 - 2799, doi;pubmed;scopus;scopus_citedby

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  • Preparation and conformational analysis of C-glycosyl β2- and β/β2-peptides

    Yoko Inaba; Toru Kawakami; Saburo Aimoto; Takahisa Ikegami; Takae Takeuchi; Takashi Nakazawa; Shigenobu Yano; Yuji Mikata

    Ten C-glycosyl β2- and β/β2-peptides with three to eight amino acid residues have been prepared. Solution and solid-phase peptide syntheses were employed to assemble β2-amino acids in which C-glycosylic substituents are attached to the C-2 position of β-amino acids. Conformational analysis of the C-glycosyl β2-peptides using NMR and CD spectra indicates that the tripeptide can form a helical secondary structure. Besides, helix directions of the C-glycosyl β/β2-peptides are governed by the configuration at the α-carbon of the peptide backbone that originates from the stereocenter of the C-glycosyl β2-amino acids. © 2009 Elsevier Ltd. All rights reserved., 31 Mar. 2009, Carbohydrate Research, 344 (5), 613 - 626, doi;pubmed;scopus;scopus_citedby

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  • Lewis acid-promoted reactions of ethenetricarboxylates with γ-CF3-substituted propargyl alcohols

    Shoko Yamazaki; Yuko Yamamoto; Yuji Mikata

    The Lewis acid-promoted reaction of an ethenetricarboxylate derivative (1) with CF3-substituted propargyl alcohols has been examined. Reaction of γ-CF3 propargyl alcohols in the presence of zinc bromide gave five-membered CF3-containing tetrahydrofurans in 66-85% yield. The CF3 group activates alkyne as an electron-withdrawing group. On the other hand, reaction of γ-trifluoromethyl-α-aryl propargyl alcohols 2 with 1 in the presence of 1 equiv of SnCl4 gave cyclobutane derivatives 6 in 29-49% yield. Formation of cyclobutane 6a arises from the [2+2] cycloaddition between ethenetricarboxylate 1 and chloroallene 8, which is produced by the reaction of propargyl alcohol 2a and SnCl4. © 2009 Elsevier Ltd. All rights reserved., 07 Mar. 2009, Tetrahedron, 65 (10), 1988 - 1994, doi;scopus;scopus_citedby

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  • Lewis acid-promoted reactions of ethenetricarboxylates with gamma-CF3-substituted propargyl alcohols

    Shoko Yamazaki; Yuko Yamamoto; Yuji Mikata

    The Lewis acid-promoted reaction of an ethenetricarboxylate derivative (1) with CF3-substituted propargyl alcohols has been examined. Reaction of gamma-CF3 propargyl alcohols in the presence of zinc bromide gave five-membered CF3-containing tetrahydrofurans in 66-85% yield. The CF3 group activates alkyne as an electron-withdrawing group. On the other hand, reaction of gamma-trifluoromethyl-alpha-aryl propargyl alcohols 2 with 1 in the presence of 1 equiv of SnCl4 gave cyclobutane derivatives 6 in 29-49% yield. Formation of cyclobutane 6a arises from the [2+2] cycloaddition between ethenetricarboxylate 1 and chloroallene 8, which is produced by the reaction of propargyl alcohol 2a and SnCl4. (C) 2009 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD, Mar. 2009, TETRAHEDRON, 65 (10), 1988 - 1994, doi;web_of_science

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  • Feasible attachment of dinuclear ruthenium complex to gold electrode surface via new ligand substitution reaction

    Hideaki Takagi; Yuji Mikata; Akio Ichimura; Toshihiro Yano; Isamu Kinoshita; Mariko Hori; Terrence J. Collins; Michael Gottschaldt; Shigenobu Yano

    A general method has been developed for accumulation of a dinuclear ruthenium complex [Ru2(dhpta)(μ-O2CCH3)2]- (H5dhpta = 1,3-diamino-2-hydroxypropane-N,N,N′,N′-tetraacetic acid) on a gold surface. The accumulation using a ligand substitution reaction of bridging acetate in the complex by terminal benzoic acid in a self-assembled monolayer (SAM) with ω-mercaptoalkoxy benzoic acid (HOOC-C6H4-O-(CH2)n-SH) (n = 4, 6, 12) is undergone. The methyl benzoate-containing alkyl disulfides capable to form SAMs on gold electrode have been synthesized utilizing reductive dimerization of the corresponding alkyl thiocyanates with tetraphenylphosphonium tetrathiomolybdate. The methyl benzoate group in the SAM was converted into benzoic acid group by base hydrolysis, which was confirmed by surface-enhanced Raman scattering measurements for silver electrode. After the ligand substitution reactions to accumulate the complex on the gold electrode surface, in the case of n = 6 and n = 12, voltammetric waves for surface confined redox process, which corresponds to RuIIIRuIII/RuIIIRuII redox couple are observed, respectively, and these surfaces of gold electrodes are covered with the complex completely. The present ligand substitution reaction should be widely applicable for the accumulation of other complexes and useful for designing of functional electrodes. © 2008 Elsevier Ltd. All rights reserved., 30 Jan. 2009, Electrochimica Acta, 54 (4), 1286 - 1291, doi;scopus;scopus_citedby

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  • Bisquinoline-based fluorescent zinc sensors

    Yuji Mikata; Azusa Yamashita; Ayano Kawamura; Hideo Konno; Yuka Miyamoto; Satoshi Tamotsu

    Several bisquinoline derivatives, N,N′-bis(2-quinolylmethyl)-N, N′-dialkylethylnediamines (alkyl = methyl, ethyl, isopropyl and t-butyl), have been synthesized and their fluorescent responses toward zinc ion were investigated. These compounds exhibit zinc ion-induced fluorescence and their intensities decrease as the alkyl groups become larger. The t-butyl derivative (BQDtBEN) exhibited negligible fluorescence even in the presence of zinc ion. The fluorescence intensity of the zinc complex of the bisquinoline derivative (BQDMEN) is higher than that of TQEN (N,N,N′,N′-tetrakis(2- quinolylmethyl)ethylenediamine), indicating that the TQEN-Zn complex has an intramolecular quenching mechanism due to the energy transfer among four quinoline rings and the remaining photoinduced electron transfer (PET) mechanism. Introduction of methoxy substituents into the quinoline ring shifted the excitation and emission wavelengths towards a lower-energy direction and increased the fluorescence intensity, which allows N,N′-bis(6-methoxy-2- quinolylmethyl)-N,N′-dimethylethylenediamine (6-MeOBQDMEN) to be used for cellular fluorescent microscopic analysis (λex = 331 nm, λem = 406 nm and = 0.28 for 6-MeOBQDMEN-Zn complex) © 2009 The Royal Society of Chemistry., 2009, Dalton Transactions, (19), 3800 - 3806, doi;pubmed;scopus;scopus_citedby

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  • Copper(ii) and zinc(ii) complexes with C-glycoside-pendant dipicolylamine (DPA)-amino acid conjugates

    Yuji Mikata; Shoko Fujii; Masami Naemura; Kyoko Takahashi; Yuka Noguchi

    A series of dipicolylamine (DPA)-functionalized amino acid ligands with a pendant C-glycosyl amide has been synthesized and complexed with Cu(ii) and Zn(ii). Amino acid derivatives equipped with a DPA unit were conjugated with C-glycosylamine prepared from acetobromoglucose in 4 steps. These ligands bind to metal ions as a N3 or N3O chelate utilizing three DPA nitrogens and carbamoyl oxygen atoms. In the crystal structures of copper(ii) and zinc(ii) complexes of AcL1 (2-(N′,N′-bis(2‴- pyridylmethyl)amino)-N-(2′-(2″,3″,4″, 6″-tetra-O-acetyl-β-d-glucopyranosyl)ethyl)acetamide, carbamoyl oxygen binds to the metal centre, however, NMR analysis reveals that AcL1 acts as a tridentate ligand in solution. The CD spectrum of the copper(ii) complex with glycine-based AcL1 at the d-d transition region indicates that the chirality at the sugar moiety does not induce an asymmetric metal coordination environment. In contrast, the chirality at the amino acid moiety for alanine and phenylalanine derivatives, AcL2 and AcL3, respectively, induces characteristic Cotton effect in the 500-800 nm region depending on the nature of the α-carbon substituent of the amino acid moiety. © The Royal Society of Chemistry 2009., 2009, Dalton Transactions, (46), 10305 - 10310, doi;pubmed;scopus;scopus_citedby

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  • Characteristic conformations and molecular packings in crystal structures of diastereomeric esters prepared from (S)-2-methoxy-2-(1-naphthyl)propanoic acid

    Akio Ichikawa; Hiroshi Ono; Yuji Mikata

    The crystal structures of the diastereomeric esters prepared from (S)-2-methoxy-2-(1-naphthyl)propanoic acid [(S)-MαNP acid] and (R)-1-octen-3-ol or (S)-β-ionol were analyzed using X-ray crystallography. The conformation of the MαNP moiety determined from NMR analyses was observed in the crystals. In these esters, the larger, more hydrophobic alcohol substituents were coupled and matched in length with the 1-naphthyl groups. The intra- and intermolecular CH/π interactions bridged the larger alcohol substituents and the 1-naphthyl groups. These crystal structures suggest that the CH/π interaction is a key function of chiral resolving agents for enantioresolution. The twisted s-cis conformation was observed at the conjugated double bonds of the β-ionol ester. Thus, MαNP acid is useful in clarifying the stereochemistry and conformations of biofunctional molecules. Normal-phase HPLC separation of the diastereomeric MαNP esters is also discussed. © 2008 Elsevier Ltd. All rights reserved., 01 Dec. 2008, Tetrahedron Asymmetry, 19 (23), 2693 - 2698, doi;scopus;scopus_citedby

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  • Isoquinoline-based TQEN family as TPEN-derived fluorescent zinc sensors

    Yuji Mikata; Azusa Yamanaka; Azusa Yamashita; Shigenobu Yano

    The hexadentate nitrogen ligands 1-isoTQEN (N,N,N′,N′- tetrakis(1-isoquinolylmethyl)ethylenediamine) and 3-isoTQEN (N,N,N′, N′-tetrakis(3-isoquinolylmethyl)ethylenediamine) have been prepared. The structures of these ligands are based on that of TPEN (N,N,N′,N′- tetrakis(2-pyridylmethyl)ethylenediamine). The introduction of a benzene ring into TPEN affords fluorescence ability upon zinc-ion binding. Compared to the quinoline isomer TQEN, isoquinoline derivatives 1-isoTQEN and 3-isoTQEN exhibit a lower-energy shift in the excitation and emission wavelengths and an enhanced fluorescence intensity, probably because of the energy-transfer mechanism between adjacent isoquinoline rings. Importantly, an increase in the Zn 2+/Cd2+ discriminating ability and a reduction in the background fluorescence induced by pH were also achieved for isoquinoline derivatives. The zinc-ion-induced fluorescence of these isoTQENs was not quenched by an addition of TPEN, which demonstrates the significantly high zinc-ion binding ability of these isoTQEN ligands. © 2008 American Chemical Society., 18 Aug. 2008, Inorganic Chemistry, 47 (16), 7295 - 7301, doi;pubmed;scopus;scopus_citedby

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  • A general route to pendant C-glycosyl 1,2- and 1,3-diamines

    Yoko Inaba; Tomomi Fujimoto; Hiroshi Ono; Makoto Obata; Shigenobu Yano; Yuji Mikata

    Practical and convenient preparations of C-glycosyl 1,2- and 1,3-alkanediamines are described. Two 1,2-ethylenediamine derivatives were synthesized from acetylated allyl α-C-glycosyl compounds via dibromination, azidation, carbohydrate deprotection, and azide reduction. Four 1,3-propanediamine derivatives were prepared from acetylated sugar halides via C-glycosylation with sodiomalononitrile, followed by the reduction of the nitrile moieties and the deacetylation of the carbohydrate moiety. These 1,3-propanediamine derivatives have the β-anomeric configurations. The methods reported here serve as general routes to access carbohydrate-diamine conjugates with C-glycosyl linkages. © 2008 Elsevier Ltd. All rights reserved., Apr. 2008, Carbohydrate Research, 343 (5), 941 - 950, doi;pubmed;scopus;scopus_citedby

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  • Preparation of C-glycoside pendant β2 - and β2,2 -amino acids

    Yoko Inaba; Shigenobu Yano; Yuji Mikata

    Facile preparations of C-glycosyl β2- and β2,2-amino acids are described. Selective formation of a β-C-glycoside linkage was achieved by the reaction of a 2,3,4,6-tetra-O-acetyl-a-D-gluco/galactopyranosyl bromide (α-acetobromo- glucose/galactose) with the carbanion of a cyanoacetate ester. Crystallization selectively afforded one of two diastereomers with respect to the chiral center at the α-carbon of the side chain (C-2), however, this compound was found to epimerize during the following nitrile reduction. Separation of the diastereomers was achieved via the Fmoc derivatives. Diastereomerically pure C-glycosyl β2,2-amino acids were prepared by diastereoselective alkylation of C-glycosylated enolate, followed by nitrile hydrogenation. The present procedure serves as an efficient route to C-glycosylated β-amino acids containing a non-biodegradable linkage. © 2008 The Chemical Society of Japan., 2008, Bulletin of the Chemical Society of Japan, 81 (5), 606 - 616, doi;scopus;scopus_citedby

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  • Syntheses, structural characterization and photophysical properties of 4-(2-pyridyl)-1,2,3-triazole rhenium(i) complexes

    Makoto Obata; Asuka Kitamura; Akemi Mori; Chiaki Kameyama; Justyna A. Czaplewska; Rika Tanaka; Isamu Kinoshita; Toshiyuki Kusumoto; Hideki Hashimoto; Masafumi Harada; Yuji Mikata; Takuzo Funabiki; Shigenobu Yano

    Novel chelators, i.e., 4-(2-pyridyl)-1,2,3-triazole derivatives, were synthesized by means of Cu(i)-catalyzed 1,3-dipolar cycloaddition and used to prepare luminescent Re(i) complexes [ReCl(CO)3(Bn-pyta)], [ReCl(CO)3(AcGlc-pyta)] and [ReCl(CO)3(Glc-pyta)] (Bn-pyta = 1-benzyl-4-(2-pyridyl)-1,2,3-triazole, AcGlc-pyta = 2-(4-(2-pyridyl)-1,2,3- triazol-1-yl)ethyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside, Glc-pyta = 2-(4-(2-pyridyl)-1,2,3-triazol-1-yl)ethyl β-d-glucopyranoside). X-Ray crystallography of Bn-pyta and Glc-pyta indicated an azocompound-like structure while the 1,2,4-triazole isomer has an azine character. [ReCl(CO) 3(Bn-pyta)] crystallized in the monoclinic system with space group P21/n. Bn-pyta ligand coordinates with the nitrogen atoms of the 2-pyridyl group and the 3-position of 1,2,3-triazole ring, which is a very similar coordinating fashion to that of the 2,2′-bipyridine derivative. The glucoconjugated Re(i) complexes [ReCl(CO)3(AcGlc-pyta)] and [ReCl(CO)3(Glc-pyta)] hardly crystallized, and were analyzed by applying extended X-ray absorption fine structure (EXAFS) analysis. The EXAFS analyses suggested that the glucoconjugation at the 1-position of the 1,2,3-triazole makes no influence to the coordinating fashion of 4-(2-pyridyl)-1,2,3-triazole. [ReCl(CO)3(Bn-pyta)] showed a blue-shifted maximum absorption (333 nm, 3.97 × 103 M -1 cm-1) compared with [ReCl(CO)3(bpy)] (371 nm, 3.35 × 103 M-1 cm-1). These absorptions were clearly assigned to be the mixed metal-ligand-to-ligand charge transfer (MLLCT) on the basis of time-dependent density functional theory calculation. The luminescence spectrum of [ReCl(CO)3(Bn-pyta)] also showed this blue-shifted feature when compared with that of [ReCl(CO) 3(bpy)]. The luminescence lifetime of [ReCl(CO)3(Bn-pyta)] was determined to be 8.90 μs in 2-methyltetrahydrofuran at 77 K, which is longer than that of [ReCl(CO)3(bpy)] (3.17 μs). The blue-shifted electronic absorption and elongated luminescence lifetime of [ReCl(CO) 3(Bn-pyta)] suggested that 4-(2-pyridyl)-1,2,3-triazole functions as an electron-rich bidentate chelator. © The Royal Society of Chemistry 2008., 2008, Dalton Transactions, (25), 3292 - 3300, doi;pubmed;scopus;scopus_citedby

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  • Regioselective transformation of octaethylporphyrin into a phytoporphyrin analogue

    Michio Kunieda; Yuji Mikata; Hitoshi Tamiaki

    (Chemical Equation Presented) An octaethylporphyrin derivative, 1, possessing an exo-five-membered ring fused at the 13- and 15-positions was oxidized by osmium tetroxide to give two isomeric chlorins, 3 and 5, possessing β,β′-dihydroxy groups at the A- and C-rings, respectively. Single dehydration of 2,3-dihydroxy-chlorin 3 gave a mixture of 2- and 3-(1-hydroxyethyl)-porphyrins 7, while that of 12,13-dihydroxychlorin 5 resulted in the sole formation of 131-hydroxyporphyrin 9. The latter was modified smoothly to the phytoporphyrin analogue 2, whose molecular skeleton was similar to that of naturally occurring chlorophylls possessing a 13 1-oxo group fixed on an exo-five-membered ring. © 2007 American Chemical Society., 14 Sep. 2007, Journal of Organic Chemistry, 72 (19), 7398 - 7401, doi;pubmed;scopus;scopus_citedby

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  • Characterization of azulenylphosphine derivatives. Unexpected debromination and its synthetic utility in the preparation of 2-substituted azulene

    A. F.M. Mustafizur Rahman; Toshihiro Murafuji; Toshihisa Shibasaki; Kouichi Suetake; Kei Kurotobi; Yoshikazu Sugihara; Nagao Azuma; Yuji Mikata

    (1,3-Dihalo-2-azulenyl)diphenylphosphines 2 [halogen = Cl (a), Br (b)] and homologous bis(1,3-dihalo-2-azulenyl)phenylphosphines 4 have been synthesized, and the effect of the nonalternant azulenyl group on the reactivity and properties of these phosphines has been studied in comparison with that of the group IS congeners. The electronic structure of the nonalternant conjugation is dramatically affected by the change in the valency at the phosphorus. Thus, oxidation of 2 and 4 with hydrogen peroxide proceeded with a dramatic color change from green to blue, giving the corresponding phosphine oxides 3 and 5, respectively, in high yield. Similar color changes were observed when a solution of each phosphine, 2b and 4b, was left standing under ambient conditions, while 2a, 4a, and (2-azulenyl)diphenylphosphine (7) showed no such changes. (1-Bromo-2-azulenyl)diphenylphosphine oxide (9) was isolated from the solution of 2b. This unexpected reaction was found to occur via electrophilic substitution at the five-membered ring through protonation. The bismuth and antimony congeners of 2b showed no such reactivity, suggesting that the higher nucleophilicity of the phosphorus atom was the deciding factor. Such debromination of 2b may be ascribed to the steric congestion around the bromine atom, which is inferred from the X-ray crystallographic study. The unexpected reaction was successfully applied to a convenient synthesis of 2-substituted azulene using triphenylphosphine as a reagent for debromination. The 13C NMR study shows the enhanced π-polarization in the azulenyl group of the phosphine oxides compared to that of the parent phosphines, but the degree is not as marked as that observed in the bismuth and antimony systems. Comparison of the crystal structure of 3b with that of 9 with respect to the intermolecular interaction between the azulenyl groups showed that the slight structural change in the nonalternant azulenyl group brings about a dramatic change in the packing. Thus, 3b has head-to-tail π-π stacking, but 9 forms a mutual halogen-hydrogen interaction of the bromine atom with a hydrogen atom of its positively charged seven-membered ring. © 2007 American Chemical Society., 04 Jun. 2007, Organometallics, 26 (12), 2971 - 2977, doi;scopus;scopus_citedby

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  • Facile synthesis of 2-(β-C-glucopyranosyl)-β-amino acid: a new class of glycopeptide building block

    Yoko Inaba; Shigenobu Yano; Yuji Mikata

    A convenient preparation of both stereoisomers of a (2R)/(2S)-2-C-glycosylated β-amino acid is described. β-C-Glycoside was formed by the reaction of α-acetobromoglucose with carbanion of cyanoacetate. The steric bulk of the C-glycoside moiety does not hinder amino acid coupling, showing the utility of this carbohydrate-containing building block for glycopeptide synthesis. © 2006 Elsevier Ltd. All rights reserved., 05 Feb. 2007, Tetrahedron Letters, 48 (6), 993 - 997, doi;scopus;scopus_citedby

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  • Control of intramolecular ether-oxygen coordination in the crystal structure of copper(II) complexes with dipicolylamine-based ligands

    Yuji Mikata; Tomomi Fujimoto; Yuko Sugai; Shigenobu Yano

    Thirteen crystal structures of copper(II) complexes with a series of dipicolylamine (DPA)-derived ligands, N-(2-methoxyethyl)-N,N-bis(2- pyridylmethyl)amine (L1), N-[2-(2-hydroxyethyloxy)ethyl]-N,N-bis(2- pyridylmethyl)amine (L2) and N-(3-methoxypropyl)-N,N-bis(2-pyridylmethyl)amine (L3), have been determined and the factors that control the coordination of the ether-oxygen atom of these ligands to the copper centre are discussed. Complexes that have +1 or +2 charges exhibit coordination of the ether-oxygen atom, whereas neutral complexes in which two anions are bound to the copper(II) centre tend to lose the oxygen coordination. Upon chelation of the oxygen atom, L3 forms a six-membered chelate ring with respect to the 3-aminopropyl ether moiety whereas L1 and L2 form a five-membered chelate. This difference, especially in the nitrate and bromide complexes, determines whether the ether-oxygen atom chelates to the metal centre to give a monocationic complex, or the second anion coordinates to the metal centre to form the ether-free, neutral complex. The terminal anchor hydroxy group of L2 facilitates the ether-oxygen coordination via a hydrogen bond interaction to the donor atom located trans to the aliphatic nitrogen atom in the basal plane. © Wiley-VCH Verlag GmbH & Co. KGaA, 2007., 2007, European Journal of Inorganic Chemistry, (8), 1143 - 1149, doi;scopus;scopus_citedby

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  • Consideration of molecular arrangements in regio- and enantioselective reduction of an NAD model compound controlled by carbonyl oxygen orientation

    Yuji Mikata; Shiho Aida; Yoko Inaba; Shigenobu Yano

    The regio- and enantioselectivity of the reduction of an NAD model compound having axial chirality with respect to the C3(quinolinium)- C(carbonyl) bond, 3-piperidinylcarbonyl-1,2,4-trimethylquinolinium ion (1), by using several reducing agents is described. Reaction of 1 with sodium hydrosulfite affords the 1,4-reduced product, 3-piperidinylcarbonyl-1,2,4- trimethyl-1,4-dihydroquinoline (2), with low enantioselectivity, whereas sodium borohydride promotes 1,2-reduction, affording 3-piperidinylcarbonyl-1,2,4- trimethyl-1,2-dihydroquinoline (3) as the sole product in a moderate enantioselectivity. When 1 was reduced by the chiral NADH model compound, 2,4-dimethyl-3-(N-α-methylbenzylcarbamoyl)-1-propyl-1,4-dihydropyridine (Me2PNPH (4)), the regioselectivity and enantioselectivity of the reaction were significantly altered by the stereochemistry of 1 and 4. An achiral NADH model compound, 1-propyl-1,4-dihydronicotinamide (PNAH (5)) exhibited both high regio- and enantioselectivities. The product selectivity reflects the change in molecular arrangement in the transition state of the reaction and reveals the relative importance of the parameters governing the molecular arrangement in the reaction. © The Royal Society of Chemistry 2007., 2007, Organic and Biomolecular Chemistry, 5 (23), 3834 - 3841, doi;pubmed;scopus;scopus_citedby

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  • Asymmetric sulfur atom coordination in a copper(ii) dipicolylamine (DPA) complex with a thioglycoside ligand

    Yuko Sugai; Shoko Fujii; Tomomi Fujimoto; Shigenobu Yano; Yuji Mikata

    The 2,2′-dipicolylamine (DPA)-tethered thioglycoside ligand, N,N-bis(2-pyridylmethyl)-2-aminoethyl 1-deoxy-1-thio-2,3,4,6-tetra-O-acetyl- β-d-glucopyranoside (sL1), has been prepared and its copper(ii) complex synthesized. Using copper(ii) chloride, the copper complex was isolated as a chloride-bound species formulated as Cu(sL1)Cl(ClO4) (1). The corresponding O-glycoside complex (Cu(L1)Cl(ClO4), 2) was also prepared using L1 (N,N-bis(2-pyridylmethyl)-2-aminoethyl 2,3,4,6-tetra-O-acetyl- β-d-glucopyranoside), and both complexes were characterized and compared by means of X-ray crystallography, cyclic voltammetry, electronic absorption and circular dichroism (CD) spectra. Although both complexes exhibited similar copper coordination geometries, the absolute configuration of the O/S chiral center generated by the copper coordination was inverted. The electronic and CD spectra of acetonitrile solutions of 1 and 2 were different likely due to the presence of a copper-sulfur charge-transfer band for 1. Complex 1 also exhibits a large Cotton effect around 700 nm. The corresponding d-d transition of the copper(ii) center reveals that the asymmetric copper-sulfur (oxygen) coordination remains even in solution. © The Royal Society of Chemistry., 2007, Dalton Transactions, (33), 3705 - 3709, doi;pubmed;scopus;scopus_citedby

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  • Quinoline-based tetradendate nitrogen ligands stabilize the bis(-oxo) dinuclear manganese(iii,iii) core

    Yuji Mikata; Haruka So; Azusa Yamashita; Ayano Kawamura; Masahiro Mikuriya; Kôichi Fukui; Akio Ichimura; Shigenobu Yano

    Quinoline-based, tetradentate nitrogen ligands, N,N′-bis(2- quinolylmethyl)-N,N′-dialkyl-1,2-ethanediamine (alkyl = methyl, bqdmen; ethyl, bqdeen; isopropyl, bqdpen), have been investigated as the supporting ligands for the formation of bis(-oxo) dinuclear manganese complexes. Bis(-oxo)Mn2(iii,iii) complexes 1 and 2 were obtained for bqdmen and bqdeen, respectively, as evidenced by X-ray crystallography, whereas bqdpen did not afford any manganese complexes due to its steric bulk. Complexes 1 and 2 exhibit highly positive Mn2(iii,iii)/Mn2(iii,iv) and Mn2(iii,iv)/Mn2(iv,iv) redox couples relative to the corresponding pyridine-ligated (-O)2Mn2(iii,iii) complexes. © The Royal Society of Chemistry., 2007, Dalton Transactions, (30), 3330 - 3334, doi;pubmed;scopus;scopus_citedby

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  • Regioselective modification of octaethylporphyrin to a phytoporphyrin derivative possessing 131-oxo group fixed on an exo-five-membered ring, similar to molecular structures of naturally occurring photoactive chlorophylls

    MIKATA Yuji; M. Kunieda; Y. Mikata; H. Tamiaki

    2007, J. Org. Chem., 72 (19), 7398-7401

  • Methoxy-substituted TQEN family of fluorescent zinc sensors

    Yuji Mikata; Motoko Wakamatsu; Ayano Kawamura; Natsuko Yamanaka; Shigenobu Yano; Akira Odani; Kazuko Morihiro; Satoshi Tamotsu

    Two methoxy-substituted TQEN (N,N,N′,N′-tetrakis(2- quinolylmethyl)ethylenediamine) derivatives, T(MQ)EN (N,N,N′,N′- tetrakis(6-methoxy-2-quinolylmethyl)ethylenediamine) and T(TMQ)EN (N,N,N′,N′-tetrakis(5,6,7-trimethoxy-2-quinolyl-methyl) ethylenediamine), have been prepared, and their fluorescence properties with respect to Zn2+ coordination were investigated. Introduction of a methoxy substituent at 6-position of the quinoline ring enhances the fluorescence intensity by 10-fold, and the three methoxy substituents in the 5,6,7-positions afford significant enhancement of the long-wavelength component of the fluorescence of zinc complex. The substituents did not alter the binding affinity of these compounds toward zinc ion significantly. T(MQ)EN was proved to be effective in detection of zinc ion in cells by fluorescent microscopy. © 2006 American Chemical Society., 13 Nov. 2006, Inorganic Chemistry, 45 (23), 9262 - 9268, doi;pubmed;scopus;scopus_citedby

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  • Erratum: Control of oxygen atom chirality and chelate ring conformation by protected/free sugar hydroxyl groups in glucose-pendant dipicolylamine- copper(II) complexes (Inorganic Chemistry (2004) 43 (4780))

    Yuji Mikata; Yuko Sugai; Shlgenobu Yano

    20 Mar. 2006, Inorganic Chemistry, 45 (6), 2768, doi;scopus;scopus_citedby

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  • Inhibition of jack bean urease by organobismuth compounds

    Toshihiro Murafuji; Takako Azuma; Youhei Miyoshi; Motoko Ishibashi; A. F.M.Mustafizur Rahman; Kouto Migita; Yoshikazu Sugihara; Yuji Mikata

    Inhibitory activity of organobismuth compounds, triarylbismuthanes 1 and their dihalides 2 and 3, was examined against jack bean urease. Besides triarylbismuth dichlorides 2, triarylbismuth difluorides 3 and bismuthanes 1 exhibited the activity. Of all these compounds, triphenylbismuth difluoride 3a and tris(4-fluorophenyl)bismuth dichloride 2b showed the highest activity. These results indicate that generation of the inhibitory effect is not always governed by the Lewis acidity at the bismuth center. Such a tendency of inhibition by the organobismuth compounds is in good accord with that observed in the antibacterial activity against Helicobacter pylori, suggesting that H. pylori-produced urease may be a therapeutic target by bismuth-based drugs. © 2005 Elsevier Ltd. All rights reserved., 15 Mar. 2006, Bioorganic and Medicinal Chemistry Letters, 16 (6), 1510 - 1513, doi;pubmed;scopus;scopus_citedby

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  • Novel oxygen chirality induced by asymmetric coordination of an ether oxygen atom to a metal center in a series of sugar-pendant dipicolylamine copper(II) complexes

    Yuji Mikata; Yuko Sugai; Makoto Obata; Masafumi Harada; Shigenobu Yano

    Six sugar-pendant 2,2′-dipicolylamine (DPA) ligands (L1-3 and L′1-3) have been prepared. OH-protected and unprotected D-glucose, D-mannose, and D-xylose were attached to a DPA moiety via an O-glycoside linkage. X-ray crystallography of the copper(II) complexes (1-5) with these ligands revealed that the anomeric oxygen atom is coordinated to the metal center in the solid state, generating a chiral center at the oxygen atom. The CD spectra of these copper complexes in methanol or aqueous solution exhibit Cotton effects in the d-d transition region, which indicates that the ether oxygen atoms remain coordinated to the metal center and the oxygen-atom chirality is preserved even in solution. For complexes 1 and 2, the inverted oxygen-atom chirality and chelate-ring conformation in the solid state are well correlated with the mirror-image CD spectra in methanol solution. The concomitant inversion of the asymmetric configuration around the copper center was also observed in a methanol solution of complex 3 and a pyridine solution of complex 2. The square-pyramidal/octahedral copper(II) centers also exhibited characteristic absorption and CD spectra. © 2006 American Chemical Society., 20 Feb. 2006, Inorganic Chemistry, 45 (4), 1543 - 1551, doi;scopus;scopus_citedby

    Scientific journal

  • N,N,N′,N′-tetrakis(2-quinolylmethyl)-2-hydroxy-1, 3-propanediamine (Htqhpn) as a supporting ligand for a low-valent (α-O)2 tetranuclear manganese core

    Yuji Mikata; Motoko Wakamatsu; Haruka So; Yuriko Abe; Masahiro Mikuriya; Kôichi Fukui; Shigenobu Yano

    A new heptadentate N6-O1 ligand, N,N,N′,N′-tetrakis(2- quinolylmethyl)-2-hydroxy-1,3-propanediamine (Htqhpn), was synthesized and used to generate compounds with linearly ordered MnIIMnIII MnIIIMnII tetranuclear cores. This is the lowest valent tetranuclear manganese complex that exhibits a (μ2-O) 2Mn2 core in the molecule. The electron paramagnetic resonance and magnetic measurements of these tetranuclear complexes suggest moderately strong antiferromagnetic coupling for the central Mn III2 core, with weak coupling between the MnII and MnIII centers. © 2005 American Chemical Society., 17 Oct. 2005, Inorganic Chemistry, 44 (21), 7268 - 7270, doi;scopus;scopus_citedby

    Scientific journal

  • Carbohydrate-appended 2,2′-dipicolylamine metal complexes as potential imaging agents

    Tim Storr; Yuko Sugai; Cheri A. Barta; Yuji Mikata; Michael J. Adam; Shigenobu Yano; Chris Orvig

    Three discrete carbohydrate-appended 2,2′-dipicolylamine ligands were complexed to the {M(CO)3}+ (M = 99mTc/ Re) core: 2-(bis(2-pyridinylmethyl)amino)ethyl-β-D-glucopyranoside (L 1), 2-(bis(2-pyridinylmethyl)amino)ethyl-β-D-xylopyranoside (L2), and 2-(bis(2-pyridinylmethyl)amino)ethyl-α-D- mannopyranoside (L3). An ethylene spacer is used to separate the carbohydrate moiety and the dipicolylamine (DPA) function in all three ligands. The Re complexes [Re(L1-3)(CO)3]Br were characterized by 1H and 13C 1D/2D NMR spectroscopies, which confirmed the pendant nature of the carbohydrate moieties in solution. NMR measurements also established the long-range asymmetric effect of the carbohydrate functions on the chelating portion of the ligand. One analogue, [Re(L1)(CO) 3]Cl, was characterized in the solid state by X-ray crystallography. Further characterization was provided by IR spectroscopy, elemental analysis, conductivity, and mass spectrometry. Radiolabeling of L1-L 3 with [99mTc(H2O)3(CO) 3]+ afforded high yield compounds of identical character to the Re analogues. The radiolabeled compounds were found to be stable toward ligand exchange in the presence of a large excess of either cysteine or histidine over a 24-h period. © 2005 American Chemical Society., Apr. 2005, Inorganic Chemistry, 44 (8), 2698 - 2705, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • A glucosamine-dipicolylamine conjugate of99mTc(I) and 186Re(I) for use in imaging and therapy

    Tim Storr; Cara L. Fisher; Yuji Mikata; Shigenobu Yano; Michael J. Adam; Chris Orvig

    The synthesis and metal complexation of a glucosamine-appended 2,2′-dipicolylamine ligand to the tricarbonyls of 99mTc and 186Re is described; the ligand was found to bind in a tridentate fashion with the glucosamine function remaining pendant, and the 99mTc complex was found to exhibit exceptional stability towards in vitro ligand exchange experiments. © The Royal Society of Chemistry 2005., 21 Feb. 2005, Dalton Transactions, (4), 654 - 655, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Tetrakis(2-quinolinylmethyl)ethylenediamine (TQEN) as a new fluorescent sensor for zinc

    Yuji Mikata; Motoko Wakamatsu; Shigenobu Yano

    A new fluorescent sensor for zinc that binds 1 equivalent of zinc ion, N,N,N′,N′-tetrakis(2-quinolylmethyl)-ethylenediamine (TQEN), has been prepared and characterized. Zinc-bound TQEN exhibits fluorescence around 383 nm upon excitation at 317 nm, while free TQEN emits very weak fluorescence. UV-Vis and 1H NMR spectral changes also detected the binding of TQEN with zinc ion. The crystal structure of zinc complex with TQEN was determined by X-ray crystallography and compared with that of the TPEN-Zn complex (TPEN = N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine). The binding affinity of TQEN with zinc ion is very high (Kd < 1 μM in aqueous dmf solution). Competition experiments reveal that the zinc-binding affinity of TQEN is lower than the parent, strong metal ion chelator TPEN, and comparable to EGTA (EGTA = ethylene glycol-bis(2-aminomethyl)-N,N,N′, N′-tetraacetic acid)., 07 Feb. 2005, Dalton Transactions, (3), 545 - 550, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Cellular uptake and photocytotoxicity of glycoconjugated chlorins in HeLa cells

    Shiho Hirohara; Makoto Obata; Shin Ichi Ogata; Chikara Ohtsuki; Suguru Higashida; Shun Ichiro Ogura; Ichiro Okura; Makiko Takenaka; Hiroshi Ono; Yuko Sugai; Yuji Mikata; Masao Tanihara; Shigenobu Yano

    Eight 5,10,15,20-tetrakis[3- or 4-(β-D-glycopyranosyloxy)phenyl]chlorins were synthesized by means of the Whitlock method with diimide reduction and purified by reversed-phase thin layer chromatography (RP-TLC). All compounds were characterized by 1H NMR spectroscopy, electron-spray ionization time-of-flight mass spectrometry (ESI-TOF MS), and UV-Vis spectroscopy. ESI-TOF MS could detect the 2H difference in molecular weight between a glycoconjugated chlorin and its corresponding porphyrin (i.e., 5,10,15,20-tetrakis[3- or 4-(β-D-glycopyranosyloxy)phenyl]porphyrin). The cellular uptake of the eight chlorins was evaluated in HeLa cells. All glycoconjugated chlorins showed higher cellular uptake than tetraphenylporphyrin tetrasulfonic acid (TPPS), and 5,10,15,20-tetrakis[3-(β-D-xylopyranosyloxy)phenyl]chlorin showed 50-fold higher uptake than TPPS. The photocytotoxicity of 5,10,15,20-tetrakis[3-(β-D-glucopyranosyloxy)phenyl]chlorin, 5,10,15,20-tetrakis[3-(β-D-xylopyranosyloxy)phenyl]chlorin and TPPS towards HeLa cells was examined at the concentration of 2 × 10-7 M (mol/dm3). These photosensitizers had no cytotoxicity in the dark, but their photocytotoxicity decreased in the order of 5,10,15,20-tetrakis[3-(β-D-glucopyranosyloxy)phenyl]chlorin > 5,10,15,20-tetrakis[3-(β-D-xylopyranosyloxy)phenyl]chlorin > TPPS. The results indicate that the photocytotoxicity is not related simply to cellular uptake. © 2004 Elsevier B.V. All rights reserved., 14 Jan. 2005, Journal of Photochemistry and Photobiology B: Biology, 78 (1), 7 - 15, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Novel carbohydrate-appended metal complexes for potential use in molecular imaging

    Tim Storr; Makoto Obata; Cara L. Fisher; Simon R. Bayly; David E. Green; Izabela Brudziñska; Yuji Mikata; Brian O. Patrick; Michael J. Adam; Shigenobu Yano; Chris Orvig

    Seven discrete sugar-pendant diamines were complexed to the {M(CO) 3}+ (99mTc/Re) core: 1,3-diamino-2-propyl β-D-glucopyranoside (L1), 1,3-diamino-2-propyl β-D-xylopyranoside (L2), 1,3-diamino-2-propyl α-D-mannopyranoside (L3), 1,3-diamino-2-propyl α-D-galactopyranoside (L4), 1,3-diamino-2-propyl β-D-galactopyranoside (L5), 1,3-diamino-2-propyl β-(α-D-glucopyranosyl-(1,4)-D-glucopyranoside) (L6), and bis(aminomethyl)bis[(β-D-glucopyranosyloxy)methyl]methane (L7). The Re complexes [Re(L1-L7)(Br)(CO)3] were characterized by 1H and 13C 1D/2D NMR spectroscopy which confirmed the pendant nature of the carbohydrate moieties in solution. Additional characterization was provided by IR spectroscopy, elemental analysis, and mass spectrometry. Two analogues, [Re(L2)(CO)3Br] and [Re-(L3) (CO)3Br], were characterized in the solid state by X-ray crystallography and represent the first reported structures of Re organometallic carbohydrate compounds. Conductivity measurements in H 2O established that the complexes exist as [Re(L1-L 7)-(H2O)(CO)3]Br in aqueous conditions. Radiolabelling of L1-L7 with [99mTc(H 2O)3(CO)3]+ afforded in high yield compounds of identical character to the Re analogues. The radiolabelled compounds were determined to exhibit high in vitro stability towards ligand exchange in the presence of an excess of either cysteine or histidine over a 24 h period., 2005, Chemistry - A European Journal, 11 (1), 195 - 203, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • General synthesis of sugar-pendant 1,3-propanediamines containing a C-glycoside linkage

    Yuji Mikata; Yoko Inaba; Mika Morioka; Shigenobu Yano

    A straightforward route to C-glycoside linked sugar-pendant 1,3-propanediamines is described. The three-step preparation procedure involves (1) C-glycosylation of an OH-protected α-glycosyl halide with malononitrile, (2) catalytic hydrogenation of the nitriles to amines, and (3) deprotection of acetyl groups via acid-catalyzed hydrolysis. In the case of the galactose derivative, excess sodiomalononitrile promotes the second addition of a carbanion in the first step. The β-anomeric configuration was confirmed by X-ray crystallography of the glycosylated intermediates. This method demonstrates a general method to access a new class of carbohydrate-pendant C-glycoside chelators. © 2004 Elsevier Ltd. All rights reserved., 22 Nov. 2004, Tetrahedron Letters, 45 (48), 8785 - 8788, doi;scopus;scopus_citedby

    Scientific journal

  • Cellular uptake and photocytotoxicity of glycoconjugated porphyrins in HeLa cells

    Shiho Hirohara; Makoto Obata; Atsuhiro Saito; Shin Ichi Ogata; Chikara Ohtsuki; Suguru Higashida; Shun Ichiro Ogura; Ichiro Okura; Yuko Sugai; Yuji Mikata; Masao Tanihara; Shigenobu Yano

    Thirty-two glycoconjugated porphyrins were synthesized by a modification of Lindsey method in the presence of Zn(OAc)2·2H 2O as a template. The Zn2+ ion template strategy improved the yield about three-fold in the case of meta-substituted tetraphenylporphyrins. In addition, free-base porphyrins were obtained almost quantitatively by demetalation with 4 M HCl. Sixteen deacetylated glycoconjugated porphyrins were tested as candidate photodynamic therapy (PDT) drugs using HeLa cells. Most of the deacetylated glycoconjugated porphyrins showed higher cellular uptake than tetraphenylporphyrin tetrasulfonic acid (TPPS), and 5,10,15, 20-tetrakis[4-(β-D-arabinopyranosyloxy)phenyl] porphyrin (p-5d) in particular showed 18.5-fold higher uptake than TPPS. The photocytotoxicity of 5,10,15,20-tetrakis[4-(β-D-glucopyranosyloxy)phenyl] porphyrin (p-5a), p-5d and TPPS was examined with HeLa cells, using a light dose of 16 J/cm2. These photosensitizers had no cytotoxicity in the dark, but their photocytotoxicity increased in the order of TPPS < p-5a < p-5d. These results suggest p-5d is a good candidate for a PDT drug., Sep. 2004, Photochemistry and Photobiology, 80 (2), 301 - 308, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Carbonyl orientation determines regio- and enantioselectivity in 1,2-/1,4-reduction of an NAD model compound

    Yuji Mikata; Shiho Aida; Shigenobu Yano

    (Equation Presented) An optically active, axially chiral NAD model compound(1) with a quinoline ring system was reduced by the chiral NADH model compound (4), affording a mixture of 1,2- and 1,4-dihydroquinolines. The carbonyl orientation governs the molecular arrangement in the transition state of the reaction and determines the regio- and enantioselectivity of the product., 19 Aug. 2004, Organic Letters, 6 (17), 2921 - 2924, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Control of oxygen atom chirality and chelate ring conformation by protected/free sugar hydroxyl groups in glucose-pendant dipicolylamine- copper(II) complexes

    Yuji Mikata; Yuko Sugai; Shigenobu Yano

    A pair of copper(II) complexes 1 and 2 exhibit an enantiomeric chiral center at the oxygen atom that coordinates to the metal center. The configurations of the oxygen atom chirality and the chelate ring conformation are simply controlled by protected/free hydroxyl groups of the sugar moiety, yielding mirror image CD spectra. In this system, repulsive and attractive forces are used to regulate chirality on the copper-coordinated oxygen atom both in the solid state and in solution., 09 Aug. 2004, Inorganic Chemistry, 43 (16), 4778 - 4780, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis, structural characterization, and antitumor activity of palladium(II) complexes containing a sugar unit

    Izabela Brudziñska; Yuji Mikata; Makoto Obata; Chikara Ohtsuki; Shigenobu Yano

    Six palladium(II) complexes as cisplatin derivatives with a sugar unit (D-glucose, D-galactose, D-mannose, D-xylose, and maltose) have been prepared. The structural features of the complexes have been characterized by NMR spectroscopy, elemental analysis, mass spectroscopy, and X-ray crystallography. The complexes have been tested for in vivo cytotoxicity against P388 cells implanted in mice. All of Pd compounds are apparently nontoxic. A T/C value of 120% was obtained for maltose derivative at the dose of 400mg/kg, which indicates that the compound may be endowed with antitumor activity. © 2004 Elsevier Ltd. All rights reserved., 17 May 2004, Bioorganic and Medicinal Chemistry Letters, 14 (10), 2533 - 2536, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Unprecedented pendant group exchange of a porphyrinato platinum(II) in benzonitrile

    Naoko Araki; Makoto Obata; Akio Ichimura; Yuji Mikata; Shigenobu Yano

    5-(4-cyanophenyl)-10,15,20-triphenylporphyrinato platinum(II) (3) and 5-(4-methoxycarbonyrphenyl)-10,15,20-triphenylporphyrinato platinum(II) (2) were isolated from a reaction of 5-(4-methoxycarbonylphenyl)-10,15,20-triphenyl porphyrin (1) with K2[PtCl4] in benzonitrile. Seemingly, 3 was generated through the functional group substitution reaction of the phenyl group of tetraphenylporphyrin during platinum ion insertion into 1 and was characterized by 1H NMR, mass spectroscopy, elemental analysis, and X-ray crystallography., Apr. 2004, Chemistry Letters, 33 (4), 450 - 451, doi;scopus;scopus_citedby

    Scientific journal

  • Hydrophobicity parameters (Log P) of glycoconjugated porphyrins for photodynamic therapy evaluated by reversed phase HPLC

    Shiho Hirohara; Makoto Obata; Shun Ichiro Ogura; Ichiro Okura; Suguru Higashida; Chikara Ohtsuki; Shin Ichi Ogata; Yoshiko Nishikawa; Makiko Takenaka; Hiroshi Ono; Yuji Mikata; Shigenobu Yano

    Photodynamic therapy (PDT) is one of the most effective treatments for cancer. We synthesized and characterized a series of 16 glycoconjugated porphyrins using a modification of the Lindsey method in the presence of Zn(OAc)2·2H2O as a template. The Zn2+ ion template strategy improved the yield about 3-fold in the case of meta-substituted tetraphenylporphyrins, and free-base porphyrins were obtaind almost quantitatively by demetalation with 4 M HCl. The hydrophobicity parameter (Log P) of these porphyrins was evaluated by reversed phase high-performance liquid chromatography (RP-HPLC). The Log P values ranged from +4.8 to +7.8, so that most of the compounds are amphiphilic. The effect of the glycopyranosyl unit on the hydrophobicity of these compounds is discussed on the basis of the Log P value. Copyright © 2004 Society of Porphyrins & Phthalocyanines., 2004, Journal of Porphyrins and Phthalocyanines, 8 (11), 1289 - 1292, doi;scopus;scopus_citedby

    Scientific journal

  • Detection of 1270 nm emission from singlet oxygen and photocytotoxic property of sugar-pendant [60] fullerenes

    Yuji Mikata; Satowa Takagi; Maki Tanahashi; Sayoko Ishii; Makoto Obata; Yuichi Miyamoto; Kazuhito Wakita; Tsuyoshi Nishisaka; Toru Hirano; Toshiaki Ito; Mikio Hoshino; Chikara Ohtsuki; Masao Tanihara; Shigenobu Yano

    Sugar-pendant [60] fullerene derivatives have been prepared from carbohydrate-linked azides 1a-e. Both monosugar (4a-e) and bissugar derivatives (5a-e) produce singlet oxygen (1O2) under laser irradiation (355 nm) proved by the direct observation of 1O 2 emission at 1270 nm. Monosugar derivatives exhibit photocytotoxicity varying by the attached sugar molecule. © 2003 Elsevier Ltd. All rights reserved., 16 Oct. 2003, Bioorganic and Medicinal Chemistry Letters, 13 (19), 3289 - 3292, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis of (μ-alkoxo)bis(μ-carboxylato)diruthenium complex having porphyrin moieties as a potential photo-harvesting functionality

    Norie Tanihara; Makoto Obata; Masafumi Harada; Yuji Mikata; Akihisa Hamazawa; Isamu Kinoshita; Kiyoshi Isobe; Akio Ichimura; Mikio Hoshino; Masahiro Mikuriya; Shigenobu Yano

    The ligand substitution reaction of K[Ru2(dhpta)(μ-O2CCH3)2] (H5dhpta = 1,3-diamino-2-hydroxypropanetetraacetic acid) with zinc 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrin (ZnTPP-p-COOH) afforded a diruthenium complex having porphyrin moieties, K[Ru2(dhpta)(μ-O2C-p-ZnTPP)2]. This product was characterized by UV-Vis and 1H NMR spectroscopy, and EXAFS analysis. © 2003 Elsevier Science B.V. All rights reserved., 01 May 2003, Inorganic Chemistry Communications, 6 (5), 447 - 450, doi;scopus;scopus_citedby

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  • Recent progress of functional glycoconjugated metal complexes

    Shigenobu Yano; Yuji Mikata

    Synthesis, characterizations and stereochemistry of the transition metal complexes containing glycosylamines derived from sugar molecules and polyamines have been investigated. During this study, the intelligent sugar complexes having ion recognition ability, novel sugar transformation reactions promoted by a cooperative effect of calcium ion and monoamines have been discovered. The biological activity of these metal complexes was also investigated. Antifungal nickel(II) complexes derived from amino sugars, and unprecedented sugar-dependent in vivo antitumor activity of carbohydrate-pendant cis-platinum(II) complexes are described in this article. These results suggested that the stereostructure and bioactivity of the sugar-metal complexes can be modified by varying amines and metal ions, and sugar molecules used., Oct. 2002, Bulletin of the Chemical Society of Japan, 75 (10), 2097 - 2113, doi;scopus;scopus_citedby

    Scientific journal

  • Testis-specific HMG-domain protein alters the responses of cells to cisplatin

    Deborah B. Zamble; Yuji Mikata; Christina H. Eng; Karen E. Sandman; Stephen J. Lippard

    Cisplatin is an effective agent for the treatment of testicular cancer. In the present study with mouse testicular teratocarcinoma cell extracts, we observed a deficiency in nucleotide excision repair (NER) of a DNA probe bearing a cisplatin 1,2-d(GpG) intrastrand cross-link. In contrast, repair of the cisplatin 1,3-d(GpTpG) intrastrand cross-link was still active in these cell extracts. A current working hypothesis is that complexes of HMG-domain proteins with the major cisplatin 1,2-intrastrand cross-links could enhance cisplatin cytotoxicity by blocking repair of these lesions on the genome. The family of HMG-domain proteins include a testis-specific protein, tsHMG, which might account for the altered NER in testicular cells. To test this possibility, a human cervical carcinoma cell line (HeLa) was constructed which ectopically expressed tsHMG under the control of an inducible promoter. Microscopic examination of tsHMG expression and cisplatin-induced apoptosis on a cellular level revealed that the nuclear protein did indeed modulate the cytotoxic consequences of cisplatin treatment. Also, tsHMG enhanced transcription inhibition by cisplatin. These results reveal that an HMG-domain protein can affect cellular responses to cisplatin and may be relevant to the clinical observation that cancer cells in specific tissues are particularly sensitive to cisplatin. © 2002 Elsevier Science Inc. All rights reserved., 30 Aug. 2002, Journal of Inorganic Biochemistry, 91 (3), 451 - 462, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • meso-Tetraphenylporphyrin having hexa-maltosyl and decyl chain as an amphiphilic photosensitizer toward photodynamic therapy

    Akihisa Hamazawa; Isamu Kinoshita; Brian Breedlove; Kiyoshi Isobe; Minako Shibata; Yasuko Baba; Toyoji Kakuchi; Shiho Hirohara; Makoto Obata; Yuji Mikata; Shigenobu Yano

    meso-Tetraphenylporphyrin having hexa-maltosyl and decyl chain was synthesized via dipyrromethane coupling. Its singlet oxygen producing ability and phototoxicity against the HeLa cell were estimated., 05 Mar. 2002, Chemistry Letters, (3), 388 - 389, doi;scopus;scopus_citedby

    Scientific journal

  • Novel multi-chalcogen ring systems with three different chalcogen atoms: Synthesis, structure and redox property of five-membered trichalcogenaheterocycles

    Satoshi Ogawa; Satoko Yoshimura; Noriyoshi Nagahora; Yasushi Kawai; Yuji Mikata; Ryu Sato

    The molecular structure of novel five-membered trichalcogenaheterocycles with three different chalcogen atoms, sulfur, selenium and tellurium, has been determined by crystallographic studies., 2002, Chemical Communications, 8 (17), 1918 - 1919, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Unprecedented sugar-dependent in vivo antitumor activity of carbohydrate-pendant cis-diamminedichloroplatinum(II) complexes

    Yuji Mikata; Yoshie Shinohara; Kazumi Yoneda; Yuka Nakamura; Izabela Brudziska; Tomoaki Tanase; Takashi Kitayama; Rie Takagi; Tadashi Okamoto; Isamu Kinoshita; Matsumi Doe; Chris Orvig; Shigenobu Yano

    Eight carbohydrate-pendant platinum(II) complexes have been synthesized from carbohydrate-diamine conjugates. D-Glucose, D-mannose, D-galactose, D-xylose, and L-glucose are attached to the dichloroplatinum(II) moiety by 1,3- or 1,2-diaminopropane chelates through with an O-glycoside bond. All the carbohydrate moieties reduced the toxicity inherent with platinum(II) complexes. © 2001 Elsevier Science Ltd. All rights reserved., 03 Dec. 2001, Bioorganic and Medicinal Chemistry Letters, 11 (23), 3045 - 3047, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Kinetic Studies of the TATA-binding Protein Interaction with Cisplatin-modified DNA

    Yongwon Jung; Yuji Mikata; Stephen J. Lippard

    The TATA-binding protein (TBP) recognizes the TATA box element of transcriptional promoters and recruits other initiation factors. This essential protein binds selectively to cisplatin-damaged DNA. Electrophoretic mobility shift assays were performed to study the kinetics of TBP binding both to the TATA box and to cisplatin-damaged DNA in different sequence contexts. TBP binds with high affinity (Kd = 0.3 nM) to DNA containing site-specific cisplatin 1,2-intrastrand d(GpG) cross-links. The kon and k off values for the formation of these TBP complexes are 1-3 × 105 m-1 s-1 and ∼1-5 × 10-4 S-1, respectively, similar to the corresponding values for the formation of a TBP-TATA box complex. In electrophoretic mobility shift assay competition assays, cisplatin-damaged DNA extensively sequesters TBP from its natural binding site, the TATA box. Nine DNA probes were prepared to determine the flanking sequence dependence of TBP binding to cisplatin-modified DNA. TBP clearly displays sequence context selectivity for platinated DNA, very similar to but not as dramatic as that of the high mobility group protein HMGB1. When TBP was added to an in vitro nucleotide excision repair assay, it specifically shielded cisplatin-modified 1,2-(GpG) intrastrand cross-links from repair. These results indicate that TBP is likely to be a key protein in mediating the cytotoxicity of cisplatin., 23 Nov. 2001, Journal of Biological Chemistry, 276 (47), 43589 - 43596, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Promotion of radiation-induced formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine by nitro 5-deazaflavin derivatives

    Tetsuji Kawamoto; Yoshihiro Ikeuchi; Yuji Mikata; Maki Kishigami; Shigenobu Yano; Chieko Murayama; Tomoyuki Mori; Fumio Yoneda

    6-Nitro- and 8-nitro-5-deazaflavin derivatives have been found to enhance prominently the radiation-induced formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) at the expense of formation of 2,6-diamino-4-hydroxy-5-formamidopyrimidine nucleosides (FapydGuo) both in deaerated and in N 2O saturated aqueous 2′-deoxyguanosine solutions. The radiosensitizing capacity of a 9-nitro-5-deazflavin derivative was observed only in the N 2O saturated aqueous solutions. © 2001 Elsevier Science Ltd., 09 Jul. 2001, Bioorganic and Medicinal Chemistry Letters, 11 (13), 1745 - 1748, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Laser-induced photo-cross-linking of cisplatin-modified DNA to HMG-domain proteins

    Y. Mikata; Q. He; S. J. Lippard

    Laser-induced photo-cross-linking was investigated for DNA, modified with cisplatin at specific sites, bound to structure-specific recognition domains of proteins in the high-mobility group (HMG) class. The efficiency of photo-cross-linking depends on the wavelength and power of the laser, the nature of the protein domain, and the oligodeoxyribonucleotide sequences flanking the platinated site. Introduction of 5-iodouridine at thymine sites of the oligodeoxyribonucleotide as an additional photoreactive group did not increase the photo-cross-linking yield. Formation of platinum-mediated DNA - DNA interstrand cross-linking observed previously upon irradiation with 302 nm light [Kane, S. A., and Lippard, S. J. (1996) Biochemistry 35, 2180-2188] was significantly reduced with laser irradiation. HMG1 domain B is superior to domain A for platinum-mediated photo-cross-linking, a result attributed to the different positioning of the proteins with respect to the platinum adduct and the greater ability of domain B to access photolabilized platinum in the major groove. Studies with proteins containing specifically mutated amino acids, and with DNA probes in which the sequences flanking the platinum cross-link site were varied, suggest that the most effective photo-cross-linking occurs for protein domains bound symmetrically and flexibly to cisplatin-modified DNA. The thermodynamic equilibrium between the protein-platinated DNA complex and its components, revealed in gel electrophoretic mobility shift assays (EMSAs), is significantly shifted to the right upon irreversible photo-cross-linking. Thus, only upon photo-cross-linking can the interaction of cisplatin - DNA 1,3-intrastrand d(GpTpG) or interstrand cross-links with HMG1 domain B protein be detected. Photo-cross-linking is thus an effective tool for investigating the interaction of cisplatin-modified DNA with damage-recognition proteins under heterogeneous conditions such those in cell extracts or living cells., 26 Jun. 2001, Biochemistry, 40 (25), 7533 - 7541, pubmed;scopus;scopus_citedby

    Scientific journal

  • Sugar-pendant diamines

    Y. Mikata; Y. Shinohara; K. Yoneda; Y. Nakamura; K. Esaki; M. Tanahashi; I. Brudziñska; S. Hirohara; M. Yokoyama; K. Mogami; T. Tanase; T. Kitayama; K. Takashiba; K. Nabeshima; R. Takagi; M. Takatani; T. Okamoto; I. Kinoshita; M. Doe; A. Hamazawa; M. Morita; F. Nishida; T. Sakakibara; C. Orvig; S. Yano

    A set of 1,3-propanediamine derivatives connected to carbohydrates (5) has been prepared in four steps from peracetylated sugar and 1,3-dibromo-2-propanol in 60-73% yields. D-Glucose, D-mannose, D-galactose, D-xylose, D-ribose, and maltose are utilized as sugar molecules in this work. The diamine moiety was connected to the C1 carbon of the glycopyranose ring via an O-glycoside bond. All of the anomeric configurations and sugar puckering conformations, except in the D-maltose derivative, were determined by X-ray crystallography of the diazido or dibromo precursors. While glycosidation of peracetylated galactopyranose with 1,3-dibromo-2-propanol in the presence of boron trifluoride afforded both anomers, the neighboring group participation of the 2-acetoxy group yielded a single anomer for the other substrates. This method has been used to synthesize a library of sugar-pendant diamines including an OH-protected derivative (6), and an N,N′-diisopropyl-substituted derivative (7). A similar series of reactions using 2,3-dibromo-1-propanol gave ethylenediamine-type derivatives (11), and bis(bromomethyl)bis(hydroxymethyl)methane (12) gave bisglucose-pendant derivatives (16)., 01 Jun. 2001, Journal of Organic Chemistry, 66 (11), 3783 - 3789, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • NAD/NADH models with axial/central chiralities: Superiority of the quinoline ring system

    Y. Mikata; K. Mizukami; K. Hayashi; S. Matsumoto; S. Yano; N. Yamazaki; A. Ohno

    Precursors of NAD model compounds 1c and 3a,b were successfully resolved into their atropisomers with respect to carbamoyl rotation. Atropisomers of quinoline derivatives are much more stable than pyridine derivatives as determined by cyclic voltammetry and X-ray crystallography. The 1,4-reduction of NAD model compound 4 was successfully achieved, affording novel NADH model compound 5. The rotational properties of the side chain of 5 were investigated by means of dynamic NMR. The rotational rate and syn/anti ratio, which indicate the orientation between carbonyl oxygen and hydrogen at the 4-position, are significantly affected by addition of magnesium ion. In the rotational transition state, the double-bond character of the Ccarbonyl-Namide bend is disrupted judging from the activation parameters. The oxidation of chiral 5 with p-benzoquinone in the presence of magnesium ion catalyst gave predominantly one enantiomer of 4. On the other hand, oxidation of 5 with p-chloranil (tetrachloro-p-benzoquinone) in the absence of magnesium ions affords the opposite enantiomer of 4 as the major product. The product enantiomer ratio is parallel to the syn/anti ratio in the starting material, indicating the importance of ground state conformation to stereochemistry of the reaction., 09 Mar. 2001, Journal of Organic Chemistry, 66 (5), 1590 - 1599, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis, structure and spectroscopic characteristics of 2 '-boryl-4 ''-dimethylaminochalcones. Effect of an intramolecular boron-oxygen coordinate bond to the conjugated system

    T Murafuji; K Sugimoto; S Yanagimoto; T Moriya; Y Sugihara; Y Mikata; M Kato; S Yano

    2'-Diethylboryl4 " -dimethylaminochalcone (1) and the related compounds (4)-(7) bearing a dioxyboryl group in the 2'-position were synthesized, and the effect of the intramolecular boron-oxygen coordinate bond on the spectroscopic characteristics of 4 " -dimethylaminochalcone chromophore was examined by comparison with 4 " -dimethylaminochalcone (2) using UV/NIS and fluorescence spectra., PERGAMON-ELSEVIER SCIENCE LTD, Feb. 2001, HETEROCYCLES, 54 (2), 929 - +, web_of_science

    Scientific journal

  • Substitution at the chiral bismuth center of optically pure diastereomeric iodobismuthanes bearing an intramolecular Bi-N coordination bond. Inversion of the configuration by aryl-Grignard reagents

    Toshihiro Murafuji; Izumi Makabe; Kazuyoshi Nishio; Yoshikazu Sugihara; Yuji Mikata; Shigenobu Yano

    Optically pure diastereomeric iodobismuthanes 3a and 3b underwent the substitution at the chiral bismuth center by 4-methylphenyl- and 4-chlorophenylmagnesium bromide to give bismuthane 4a and 4b as a single diastereomer, respectively. Each reaction was highly stereoselective. Comparison of 4a with 4b by 1H-NMR spectrum revealed that the chemical shifts of the aromatic ring protons are quite different from each other due to the anisotropic effect of the ferrocenyl group, which reflects the difference of the configuration around the chiral bismuth center. The differential 1H-NMR NOE experiments of 4a and 4b provided a critical evidence for the configuration in each compound. The X-ray crystallographic study of 4 demonstrated that the substitution proceeds with inversion of the configuration at the chiral bismuth center. © 2000 Elsevier Science S.A. All rights reserved., ELSEVIER SCIENCE SA, 06 Oct. 2000, Journal of Organometallic Chemistry, 611 (1-2), 100 - 105, web_of_science;doi;scopus;scopus_citedby

    Scientific journal

  • HMG-domain protein recognition of cisplatin 1,2-intrastrand d(GpG) cross-links in purine-rich sequence contexts

    S. M. Cohen; Y. Mikata; Q. He; S. J. Lippard

    HMG-domain proteins bind strongly to bent DNA structures, including cruciform and cisplatin-modified duplexes. Such protein-platinated DNA complexes, formed where the DNA is modified by the active cis but not the inactive trans isomer of diamminedichloroplatinum(II), are implicated in the cytotoxic mechanism of the drug. A series of oligonucleotide duplexes with deoxyguanosine nucleosides flanking a cis-[Pt(NH3)2{d(GpG)-N7(1),-N7(2)}] cross-link have been synthesized. These probes were used to determine the flanking sequence dependence of the affinity of the individual HMG domains of HMG1 toward cisplatin-modified DNA. Nine related sequences, where N1 and N2 are not dG and G*G* is the 1,2-intrastrand cisplatin adduct in N1G*G*N2, were previously investigated [Dunham, S. U., and Lippard, S. J. (1997) Biochemistry 36, 11428-11436]. Three of the seven remaining possible sequences for which N1 and/or N2 was dG were prepared here by using normal deoxyguanosine, but the rest, where N1 is dG and N2 is dA, dC, T, or dG, could not be isolated in pure form. These sequences were accessed by using the synthetic bases 7-deazaadenine and 7-deazaguanine, which lack the nucleophilic N7 atom in the purine ring. Deaza nucleotides accurately mimic the properties of the natural bases, allowing the interaction of the HMG-domain proteins with cisplatin-modified DNA to be examined. These experiments reveal that the flexibility of A·T versus G·C flanking base pairs, rather than base-specific contacts, determines HMG1domA protein selectivity. This conclusion was supported by use of mutant HMG1domA and HMG1domB proteins, which exhibit identical flanking sequence selectivity. The methods and results obtained here not only improve our understanding of how proteins might mediate cisplatin genotoxicity but also should apply more generally in the investigation of how other proteins interact with damaged DNA., AMER CHEMICAL SOC, 26 Sep. 2000, Biochemistry, 39 (38), 11771 - 11776, web_of_science;doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis and antitumor activities of novel 5-deazaflavin-sialic acid conjugate molecules

    Yoshihiro Ikeuchi; Motoko Sumiya; Tetsuji Kawamoto; Naoshige Akimoto; Yuji Mikata; Maki Kishigami; Shigenobu Yano; Takuma Sasaki; Fumio Yoneda

    6-Nitro-5-deazaflavin derivatives bearing O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-α- and β-D-galacto-non-2-ulopyranosylonate)alkyl group (sialosylalkyl group) at N(3) or N(10) and 8-amino-5-deazaflavin substituted with the sialosylalkyl group at the amino group were synthesized and their physicochemical properties as well as antitumor effects on KB and L1210 cells have been investigated. The configurations of the glycosides were determined by 1H NMR and rate of hydrolysis of the glycosidic bond. It has been found that these conjugate molecules show significant antitumor activities. Combination of an 8-amino-5-deazaflavin with the sialosylalkyl group have been found to give rise to significant increase in antitumor activities of the compound. Antitumor effects of 6-nitro-5-deazaflavin-sialic acid conjugate molecules were similar or rather weak in comparison with those of the 6-nitro-5-deazaflavin derivatives without sialosylalkyl group. Copyright (C) 2000 Elsevier Science Ltd., Aug. 2000, Bioorganic and Medicinal Chemistry, 8 (8), 2027 - 2035, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Effect of the linking position of a side chain in bis(quinolylmethyl)ethylenediamine as a DNA binding agent

    Yuji Mikata; Yoko Onchi; Maki Kishigami; Shigenobu Yano

    Two bisquinoline derivatives, N,N'-bis(2-quinolylmethyl)ethylenediamine (2-BQME) and N,N'-bis(8-quinolylmethyl)ethylenediamine (8-BQME) have been synthesized, and their ability to bind to duplex DNA was studied. 8-BQME bound to DNA more strongly than 2-BQME, judging from the extent of increase in the melting temperature of duplex DNA, the UV-vis spectral change, and ethidium displacement assay. These compounds exhibited apparent AT- specificity suggesting minor groove binding in addition to intercalation., PHARMACEUTICAL SOC JAPAN, Apr. 2000, Chemical and Pharmaceutical Bulletin, 48 (4), 477 - 479, web_of_science;doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Highly reactive and stereospecific reaction of quinoline-type NADH model compounds with methyl benzoylformate

    Yuji Mikata; Kayo Hayashi; Kiyoko Mizukami; Sawako Matsumoto; Shigenobu Yano; Norimasa Yamazaki; Atsuyoshi Ohno

    NADH model compounds with a dihydroquinoline ring can reduce methyl benzoylformate with very high reactivity and stereospecificity. Chiral column HPLC is effective in the separation and analysis of enantiomers of NADH and NAD model compounds, respectively. (C) 2000 Elsevier Science Ltd., PERGAMON-ELSEVIER SCIENCE LTD, 12 Feb. 2000, Tetrahedron Letters, 41 (7), 1035 - 1038, web_of_science;doi;scopus;scopus_citedby

    Scientific journal

  • Acid-base and metal ion-binding properties of diaminopropyl D-glucopyranoside and diaminopropyl D-mannopyranoside compounds in aqueous solution

    B Song; P Mehrkhodavandi; P Buglyo; Y Mikata; Y Shinohara; K Yoneda; S Yano; C Orvig

    For three sugar-appended diamine compounds (1,3-diamino-2-propyl beta-D-glucopyranoside (2-beta-D-Glc-pn), (2S)-2,3-diaminopropyl beta-D-glucopyranoside (1-beta-D-Glc-pn) and 1,3-diamino-2-propyl alpha-D-mannopyranoside (2-alpha-D-Man-pn)), acidity constants and stability constants with Ni2+, Cu2+ and Zn2+ have been measured (I = 0.16 M NaCl, 25 degrees C). The two acidity constants of each of the three sugar-diamines differ by 10(1.65) to 10(3.09), indicating that removal of the proton from HL+ species is more difficult than deprotonation from the fully protonated dication H2L2+. Statistical and polar effects, as well as the formation of an intramolecular hydrogen bond, may cause this increased stability of the HL+ species. The strength of the hydrogen bond and the degree of its formation (percentage) were estimated. The sugar ring has only a small influence on the intramolecular hydrogen bond formation. For the different metal ion-ligand systems, the predominating species in solution are quite different. In the Cu2+-1-beta-D-Glc-pn system, the dominant species are always CuL2+ and CuL22+ in the pH range 4 to 10, where the total ligand concentration is larger than total metal ion concentration. For Ni2+, NiL32+ is also important under these same conditions; however, for Zn2+, the hydrolysis species ZnL2(OH)(+) and ZnL2(OH)(2) predominate in the high pH region. All possible species in the system were included during the calculations, and the corresponding stability constants were determined. The hydrolysis of the metal ions themselves is important in some cases and all possible hydrolysis species were included in the fitting calculation. The stability constant plots log K versus pK yielded straight reference lines for 1,3-diamine or 1,2-diamine ligands, reflecting the complete absence of sugar oxygen atoms in the metal ion coordination. The linkage between the metal ion and the diamine residue depends solely on the basicity of the ligand., ROYAL SOC CHEMISTRY, 2000, JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, (8), 1325 - 1333, web_of_science

    Scientific journal

  • Acid-base and metal ion-binding properties of diaminopropyl D-glucopyranoside and diaminopropyl D-mannopyranoside compounds in aqueous solution

    Bin Song; Parisa Mehrkliodavandi; Peter Buglyo; Yuji Mikata; Yoshie Shinohara; Kazumi Yoneda; Shigenobu Yano; Chris Orvig

    For three sugar-appended diamine compounds (l,3-diamino-2-propyl β-o-glucopyranoside (2-β-D-Glc-pn), (25)2,3-diaminopropyl β-D-glucopyranoside (1-β-o-Glc-pn) and l,3-diamino-2-propyl a-o-mannopyranoside (2-a-DMan-pn)), acidity constants and stability constants with Ni2+, Cu2+ and Zn2+ have been measured (/= 0.16 M NaCl, 25 °C). The two acidity constants of each of the three sugar-diamines differ by 101-65 to 103'09, indicating that removal of the proton from HL+ species is more difficult than deprotonation from the fully protonated dication H2L2t. Statistical and polar effects, as well as the formation of an intramolecular hydrogen bond, may cause this increased stability of the HL+ species. The strength of the hydrogen bond and the degree of its formation (percentage) were estimated. The sugar ring has only a small influence on the intramolecular hydrogen bond formation. For the different metal ion-ligand systems, the predominating species in solution are quite different. In the Cu2+-l-β-D-Glc-pn system, the dominant species are always CuL2t and CuLf, in the pH range 4 to 10, where the total ligand concentration is larger than total metal ion concentration. For Ni2t, NiLf+ is also important under these same conditions; however, for Zn2+, the hydrolysis species ZnL2(OH)+ and ZnL2(OH)2 predominate in the high pH region. All possible species in the system were included during the calculations, and the corresponding stability constants were determined. The hydrolysis of the metal ions themselves is important in some cases and all possible hydrolysis species were included in the fitting calculation. The stability constant plots log K versus pK yielded straight reference lines for 1,3-diamine or 1,2-diamine ligands, reflecting the complete absence of sugar oxygen atoms in the metal ion coordination. The linkage between the metal ion and the diamine residue depends solely on the basicity of the ligand. ©The Royal Society of Chemistry 2000., 2000, Journal of the Chemical Society, Dalton Transactions, (8), 1325 - 1333, doi;scopus;scopus_citedby

    Scientific journal

  • Feasible Attachment of a Dinuclear Ruthenium Complex to Gold Electrode Surfaces. A Screening Method to Find Functional Electrodes

    Hideaki Takagi; Akio Ichimura; Toshihiro Yano; Isamu Kinoshita; Kiyoshi Isobe; Masaaki Abe; Yoichi Sasaki; Yuji Mikata; Tomoaki Tanase; Nao Takeshita; Chiharu Lnoue; Yumi Klmura; Shoko Endo; Kayoko Tamura; Shigenobu Yano

    A dinuclear ruthenium complex [Ru2(dhpta)(μ-O2CCH3)2] - (H5dhpta = 1,3-diamino-2-hydroxypropane-N, N, N', N'-tetraacetic acid) is accumulated on a gold surface by using the ligand substitution reaction of bridging acetate in the complex by terminal benzoate in a self-assembled monolayer with 4-(6-mercaptohexoxy)benzoic acid. The accumulated complex, which shows a surface redox couple corresponding to Ru111Ru111/Ru111Ru11, covers the gold surface completely. The ligand substitution reaction is applicable for the accumulation of other complexes and useful for the designing of functional electrodes., Dec. 1999, Electrochemistry, 67 (12), 1192 - 1193, scopus;scopus_citedby

    Scientific journal

  • Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine under anaerobic conditions by reductively activated nitro 5-deazaflavin derivatives

    Yuji Mikata; Maki Kishigami; Mamiko Nishida; Shigenobu Yano; Tetsuji Kawamoto; Yoshihiro Ikeuchi; Fumio Yoneda

    Electrolytically reduced 6- and 8-nitro-5-deazaflavin derivatives have been found to interact to react specifically with guanine base by means of cyclic voltammetry. Electrolytic reductions of 6- and 8-nitro-5-deazaflavin derivatives in the presence of the 2'-deoxyguanosine under anaerobic conditions resulted in prominent formation of 8-oxo-7,8-dihydro-2'- deoxyguanosine., 02 Aug. 1999, Bioorganic and Medicinal Chemistry Letters, 9 (15), 2141 - 2144, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Unexpectedly produced 2-tert-butyl-5-(N,N-dimethylcarbamoyl)pyridine from 2-chloro-3-(N,N-dimethylcarbamoyl)-pyridine with a tert-butyl Grignard reagent

    Yuji Mikata; Ryoko Maesaki

    The title compound, C12H18N2O, was obtained by the reaction of 2-chloro-3-(N,N-dimethylcarbamoyl)pyridine with tert-butylmagnesium chloride. The structure was confirmed by NMR spectroscopy and X-ray crystallography., 15 Jun. 1999, Acta Crystallographica Section C: Crystal Structure Communications, 55 (6), 973 - 975, doi;scopus;scopus_citedby

    Scientific journal

  • First synthesis and characterization of zinc(II) complexes containing N-glycosides derived from ethylenediamine and D-glucosamine

    Shigenobu Yano; Sahoko Inoue; Yukiko Yasuda; Tomoaki Tanase; Yuji Mikata; Toyoji Kakuchi; Taro Tsubomura; Mikio Yamasaki; Isamu Kinoshita; Matsumi Doe

    Zinc(II) complexes containing N-glycosides derived from D-glucosamine (D-GlcN) and ethylenediamine (en), [Zn(D-GlcN-en)2]X2 (1a X = Cl, 1b X2 = SO42-), were prepared and characterized by elemental analysis and nuclear magnetic resonance spectroscopy involving X-ray crystallography, where D-GlcN-en = 1-{(2-aminoethyl)amino}-2-amino-1,2-dideoxy-D-glucose. The complex cation of 1a has a nearly C2 symmetry and the central zinc atom is octahedrally coordinated by two tridentate N-glycoside ligands from D-glucosamine and ethylenediamine. The N-glycoside ligand, D-GlcN-en, ligates to the zinc atom through the C2 amino nitrogen atom of D-glucosamine and the two nitrogen atoms of the diamine in a meridional mode. The analysis of the solution conformation of the sugar ring in 1a based on vicinal coupling constants confirmed the similar structure revealed by X-ray crystallography., 07 Jun. 1999, Journal of the Chemical Society - Dalton Transactions, (11), 1851 - 1855, scopus;scopus_citedby

    Scientific journal

  • Mechanism and stereochemisty in the reaction of NAD(P)H model compounds: Conversion from central into axial chirality

    Yuji Mikata; Mutsuo Okamura

    In redox reactions involving NAD(P)H and its model compounds, it has been reported that nonsteric interactions of the carbamoyl moiety in the nicotinamide ring with metal ions and substrates determine the reaction face. In the oxidation of Me3MQPH (1), the stereochemistry of the product, Me3MQP+ (2), is influenced largely by the reactivity of the reagent employed (oxidation potential of the quinone or pKa of the amine). This interesting phenomenon has been interpreted in terms of the difference in stability between the two conformations with reference to the carbonyl rotation in the transition state. From the results of kinetic studies, the earliness/lateness of the transition state determines the product ratio. The energy difference between the two conformations in the transition state has been estimated from the temperature dependence of the product ratio. A conformational analysis of 1, the ground state, was performed using dynamic NMR. The contribution of the ground state conformation and the role of magnesium ion, which is used as a catalyst, are discussed., 1999, Reviews on Heteroatom Chemistry, 20, 207 - 226, scopus;scopus_citedby

  • Crystal Structure of Unexpectedly Produced 6-t-Butyl-3-(N, N-dimethylcarbamoyl)pyridine from 2-Chloro-3-(N, N-dimethylcarbamoyl)pyridine with t-Butyl Grignard Reagent

    MIKATA Yuji

    1999, ┣DBActa Crystallographica(/)-┫DB, C55, 973-975

  • General synthesis of useful chelating reagents having a sugar unit, 1,3-diamino-2-propyl β-D-glucopyranoside and 1,3-diamino-2-propyl α-D-mannopyranoside

    Shigenobu Yano; Yoshie Shinohara; Kaoru Mogami; Mika Yokoyama; Tomoaki Tanase; Toru Sakakibara; Fumiko Nishida; Kenichi Mochida; Isamu Kinoshita; Matsumi Doe; Kanako Ichihara; Yoshinori Naruta; Parisa Mehrkhodavandi; Péter Buglyó; Bin Song; Chris Orvig; Yuji Mikata

    Two 1,3-propanediamine derivatives bearing sugar units, 1,3-diamino-2-propyl β-D-glucopyranoside (2-β-D-Glc-pn) and 1,3-diamino-2-propyl α-D-mannopyranoside (2-α-D-Man-pn), have been prepared and characterized. The structures of two peracetylated diazides, as well as a nickel complex of glucose-type ligand, [Ni(2-β-D-Glc-pn)2SO4] have been determined by X-ray crystallography., 1999, Chemistry Letters, (3), 255 - 256, doi;scopus;scopus_citedby

    Scientific journal

  • Purification and Characterization of D-Glucosaminitol Dehydrogenase from Agrobacteriu

    Ryoko Iwamoto; Chieko Sakamoto; Keiko Tamura; Yuji Mikata; Mieko Tanaka

    D-Glucosaminitol dehydrogenase, which catalyzes the conversion of D-glucosaminitol to 3-keto-D-glucosaminitol, was purified to apparent homogeneity from extracts of Agrobacterium radiobacter. This organism has constitutively depressed levels of the enzyme but expression of the enzyme is induced by addition of D-glucosamine to the medium. Purification included ammonium sulfate fractionation and chromatography on columns of DEAE-Sephacel, Octyl-Sepharose CL-4B, and Cellulofine. The purified enzyme migrated as a single band, coinciding with dehydrogenase activities specific for D-glucosaminitol and ethanol, when electrophoresed on a 7.5% polyacrylamide gel at pH 8.0. Electrophoresis on a 12.5% PAGE in the presence of 1% SDS also yielded a single band. The enzyme had an apparent molecular mass of 79 kDa, as measured by the pattern of elution from a column of Cellulofine. The results indicated that the enzyme was a dimer of identical (or nearly identical) subunits of 39.5 kDa. D-Glucosaminitol dehydrogenase required NAD+as a cofactor and used ethanol as the preferred substrate, as well as aliphatic alcohols with 2 to 4 carbon atoms, D-glucosaminitol, D-glucosaminate, DL-allothreonine, glycerol, and erythritol as additional substrates. In 50 mM Tris-HCl buffer (pH 9.0) at 25°C, the Kmfor D-glucosaminitol, ethanol, and NAD+were 2.2, 2.0, and 0.08 mM, respectively. The enzyme had a pH optimum of 10 for D-glucosaminitol and 8.5 for ethanol. The enzyme lost substantial activity when treated with pyrazole, with certain reagents that react with sul- fhydryl groups and with Zn2+ion. The various results together suggest that the enzyme exploits different amino acid residues for the dehydrogenation of ethanol and of D-glucosaminitol. © 1999, Taylor & Francis Group, LLC. All rights reserved., 01 Jan. 1999, Bioscience, Biotechnology and Biochemistry, 63 (5), 785 - 791, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Structure and spectroscopic characteristics of 2'-diethylboryl-4''- dimethylaminochalcone bearing an intramolecular boron-oxygen coordinate bond

    T. Murafuji; Y. Sugihara; T. Moriya; Y. Mikata; S. Yano

    How formation of an intramolecular coordinate bond affects the molecular structure was examined in the structural comparison of 2'-diethylboryl-4''- dimethylaminochalcone (1) and 2'-ethylenedioxyboryl-4''-dimethylaminochalcone (2) with chloro-{2-[(4-dimethylaminostyryl) carbonyl] phenyl} (4-methyl- phenyl)] bismuthane (3) and 4''-dimethylaminochalcone (4)., 1999, New Journal of Chemistry, 23 (7), 683 - 685, doi;scopus;scopus_citedby

    Scientific journal

  • Synthesis and phototoxic property of tetra- and octa-glycoconjugated tetraphenylchlorins

    Yuji Mikata; Yoko Onchi; Minako Shibata; Toyoji Kakuchi; Hiroshi Ono; Shun Ichiro Ogura; Ichiro Okura; Shigenobu Yano

    New tetraphenylchlorin derivatives having four or eight glucose molecules were synthesized. Phototoxicity against the HeLa cell, singlet oxygen producing ability, and cell permeability were examined to evaluate the activity on photodynamic therapy of the compounds., 15 Dec. 1998, Bioorganic and Medicinal Chemistry Letters, 8 (24), 3543 - 3548, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Intercalator-linked cisplatin: Synthesis and antitumor activity of cis-dichloroplatinum(II) complexes connected to acridine and phenylquinolines by one methylene chain

    Yuji Mikata; Mika Yokoyama; Kaoru Mogami; Masako Kato; Ichiro Okura; Makoto Chikira; Shigenobu Yano

    Three novel intercalator-linked cisplatin-type platinum complexes, cis-[PtCl2(9-(2-aminoethyl)aminomethylacridine)] (1), cis-[PtCl2(4-(2-aminoethyl)aminomethyl-2-phenylquinoline)] (2), and cis-[PtCl2(8-(2-aminoethyl)aminomethyl-2-phenylquinoline)] (3) were synthesized. The structure of 1 was determined by X-ray crystallography (triclinic, space group P1̄ with a = 15.007(6), b = 15.597(4), c = 10.398(3) Å, α = 98.51(3)°, β = 96.79(3)°, β =114.61(2)°, γ = 4, R = 0.053, Rw = 0.063). The antitumor activity of the platinum complexes was investigated against the HeLa cell. Compound 3 was the most cytotoxic among the complexes synthesized here and was more effective than cisplatin. It was suggested from microscopic analysis that the acridine complex 1, which had no cytotoxicity against the HeLa cell, was not incorporated in the nucleus of the cell. Against the P388 cell, however, complex 1 gave a more therapeutic result than 3. The covalent binding ability of the cisplatin moiety was suppressed significantly in these compounds. The results of molecular mechanics showed that intercalation and covalent binding could be compatible. The cytotoxicity and DNA binding ability of phenylquinoline-type ligands were also studied to evaluate the intrinsic cytotoxicity of the intercalator. From the duplex DNA denaturation experiment and fluorescent ethidium displacement assay, the DNA binding affinities of the ligands are in agreement with the cytotoxicity of these compounds and the corresponding platinum complexes. © 1998 Elsevier Science S.A. All rights reserved., 15 Sep. 1998, Inorganica Chimica Acta, 279 (1), 51 - 57, doi;scopus;scopus_citedby

    Scientific journal

  • Structure and magnetic and electrochemical properties of (μ-aryloxo)-bis(μ-carboxylato)diruthenium(III) complexes

    Yuji Mikata; Nao Takeshita; Tomoko Miyazu; Yuki Miyata; Tomoaki Tanase; Isamu Kinoshita; Akio Ichimura; Wasuke Mori; Satoshi Takamizawa; Shigenobu Yano

    The dinuclear diruthenium complexes ligated by the (μ-aryloxo)bis(μ-carboxylato) system M[Ru2L(μ-O2CR)2] (M = Na, R = Me 1; M = Na, R = Ph 2; M = K, R = Me 3; M = K, R = Ph 4; H5L = 2-hydroxy-5-methyl-m-phenylenedimethylenedinitrilotetraacetic acid) were prepared by the reaction of [RuCl2(Me2SO)4] with L5- and carboxylic acid. The structure of the benzoate-bridged complex 4·0.5MeOH·0.5EtOH·4H2O was elucidated by X-ray crystallography. The Ru ⋯ Ru distance was 3.416 Å (average for two crystallographically independent molecules), comparable to those of (μ-alkoxo)bis(μ-carboxylato)diruthenium complexes. The magnetic properties were analysed by a general isotropic exchange Hamiltonian H = -2JS1·S2 (S1, = S2 = 1/2), yielding meaningfully large antiferromagnetic spin coupling constants (-J = 728 and 649 cm-1 for 1 and 2, respectively). The cyclic voltammogram of 4 in dmf demonstrated two reduction and one oxidation wave corresponding to the four redox states RuII2, RuIIRuIII, RuIII2,RuIIIRuIV. The intervalence coupling constant KC estimated from the potential gap between RuII2/RuIIRuIII and RuIIRuIII/RuIII2 indicated that the introduction of the μ-aryloxo bridge stabilizes the RuIIRuIII mixed-valence species., 21 Jun. 1998, Journal of the Chemical Society - Dalton Transactions, 1998 (12), 1969 - 1972, doi;scopus;scopus_citedby

    Scientific journal

  • Sugar-dependent photocytotoxic property of tetra- and octa- glycoconjugated tetraphenylporphyrins

    Yuji Mikata; Yoko Onchi; Kenji Tabata; Shun ichiro Ogura; Ichiro Okura; Hiroshi Ono; Shigenobu Yano

    New tetraphenylporphyrin derivatives having eight glucose molecules were synthesized. Phototoxicity of these compounds against the HeLa cell line were compared to tetraglycosylated tetraphenylporphyrins. The highest activity was observed for a derivative having four OH-protected glucose moieties. Singlet oxygen producing ability was also examined to explain the difference in photocytotoxicities., 18 Jun. 1998, Tetrahedron Letters, 39 (25), 4505 - 4508, doi;scopus;scopus_citedby

    Scientific journal

  • Effect of side chain location in (2-aminoethyl)aminomethyl-2- phenylquinolines as antitumor agents

    Yuji Mikata; Mika Yokoyama; Shun ichiro Ogura; Ichiro Okura; Masafumi Kawasaki; Mizuo Maeda; Shigenobu Yano

    Three new derivatives of 2-phenylquinoline having an (2- aminoethyl)aminomethyl group in 7-, 6-, or 4'-(para position of 2-phenyl ring) positions of aromatic system have been prepared. The antitumor activity of these compounds together with 8- or 4- substituted isomers against the HeLa cell is in the order of 8- > 7- > 4- ≃ 6- ≃ 4'- substituted ones, which is almost in good agreement with that of DNA-binding ability evaluated by means of DNA-titration of UV-VIS spectra, DNA melting experiment, and ethidium displacement assay. Two representative compounds (8- and 4- isomers) are confirmed to have an ability to intercalate into double stranded DNA by topoisomerase I superhelix unwinding assay., 19 May 1998, Bioorganic and Medicinal Chemistry Letters, 8 (10), 1243 - 1248, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis and evaluation of nitro 5-deazaflavinpyrrolecarboxamide(s) hybrid molecules as novel DNA targeted bioreductive antitumor agents

    Yoshitomo Kanaoka; Yoshihiro Ikeuchi; Tetsuji Kawamoto; Kiyoshi Bessho; Naoshige Akimoto; Yuji Mikata; Mamiko Nishida; Shigenobu Yano; Takuma Sasaki; Fumio Yoneda

    A series of 6-nitro-5-deazaflavins bearing at N(3) or N(10) position the pyrrolecarboxamide(s) group as DNA minor groove binder has been synthesized. These hybrid molecules show similar redox properties to those of 6-nitro-5- deazaflavins with no pyrrolecarboxamide(s) group, suggesting that they generate stable one- and two-electron reduction product(s). Electrolytic reductions of the hybrid molecules were carried out at a controlled potential under anaerobic conditions in the presence of plasmid pBR322 DNA. Significant conversions of the supercoiled circular pBR322 DNA (form I) to the open circular DNA (form II) have been found by treatment with the reductively activated 6-nitro-5-deazaflavin derivatives. Their DNA damaging effects have been found to be enhanced as the number of pyrrolecarboxamide group as the DNA binder increases. Antitumor activities of the hybrid molecules towards KB and L1210 cells were evaluated in vitro. It has been found that the antitumor effects of the compounds on KB cells slightly change and those on L1210 cells decrease as the number of the pyrrolecarboxamide group increases. These results reveal that the combination of 6-nitro-5-deazaflavin molecule with the pyrrolecarboxamide(s) group increase the DNA binding properties of the compounds, giving rise to promoted DNA damaging effects, and also suggest that the combination would affect the capacity of the compounds to act as the substrate for intracellular reductases and/or the cellular uptake of the compounds., Mar. 1998, Bioorganic and Medicinal Chemistry, 6 (3), 301 - 314, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Antifungal nickel(II) complexes derived from amino sugars against pathogenic yeast, Candida albicans

    Shigenobu Yano; Sahoko Inoue; Reiko Nouchi; Kaoru Mogami; Yoshie Shinohara; Yukiko Yasuda; Masako Kato; Tomoaki Tanase; Toyoji Kakuchi; Yuji Mikata; Takahito Suzuki; Yasuhiro Yamamoto

    Nickel(II) complexes containing N-glycosides derived from D-glucosamine (D-GlcN) and ethylenediamine (en) and trimethylene-diamine (tn), [Ni(D-GlcN- en)2]Cl2 · H2O (1) (D-GlcN-en=1-{(2-aminoethyl)amino}-2-amino-1,2- dideoxy-D-glucose) and [Ni(D-GlcN-tn)2]Cl2-4H2O (2) (D-GlcN-tn=1-{(3- aminopropyl)amino}-2-amino-1,2-dideoxy-D-glucose), are fairly stable in water at room temperature and showed effective antifungal activity against pathogenic yeast, Candida albicans, with the MIC (minimal concentration of inhibition) values of the complexes being 0.25 mM. The results obtained enzyme assays by using preparations of C. albicans chitinase fraction suggested that the sugar complexes 1 and 2 played a role of novel chitinase (chitin-degradation enzyme) inhibitor, where the modes of inhibition were competitive (K(i) = 1.3 mM for 1, K(i) = 1.8 mM for 2). The newly prepared nickel(II) complex 2 was characterized by elemental analysis, magnetic susceptibility, electronic absorption and circular dichroism spectroscopies, and an X-ray crystallographic analysis., 01 Feb. 1998, Journal of Inorganic Biochemistry, 69 (1-2), 15 - 23, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Convenient preparation of chiral ethylenediamine linked to D-glucose

    Yuji Mikata; Kazumi Yoneda; Tomoaki Tanase; Isamu Kinoshita; Doe Matsumi; Fumiko Nishida; Kenichi Mochida; Shigenobu Yano

    A useful preparation of an ethylenediamine derivative linked to d-glucose, 2,3-diaminopropyl β-D-glucopyranoside, has been described. The optically pure compound was obtained conveniently via recrystallization of the diastereomeric mixture of the diazido precursor. The stereochemistry of the ethylenediamino compound was elucidated by X-ray crystallography. Copyright (C) 1998 Elsevier Science Ltd., 1998, Carbohydrate Research, 313 (3-4), 175 - 179, doi;scopus;scopus_citedby

    Scientific journal

  • Out-of-plane orientation of the carbamoyl group in an NAD model compound: Preferred 1,3-diaxial methyl configuration

    Yuji Mikata

    The carbamoyl group in 3-(cis-2,6-dimethylpiperidinyl-carbonyl)-1-methylpyridinium iodide, C14H21N2O+ .I-, has an out-of-plane orientation in the crystalline state. The planarity of the amide moiety is conserved and the two methyl groups in the piperidine ring are both in axial configurations., 15 Oct. 1997, Acta Crystallographica Section C: Crystal Structure Communications, 53 (10), 1486 - 1488, doi;scopus;scopus_citedby

    Scientific journal

  • Synthesis, characterization, interaction with DNA, and antitumor activity of a cis-Dichloroplatinum(II) complex linked to an intercalator via one methylene chain

    Yuji Mikata; Kaoru Mogami; Masako Kato; Ichiro Okura; Shigenobu Yano

    A cisplatin-type complex tethered to acridine intercalator via one methylene chain has been synthesized. Its structure was elucidated by X-ray crystallography. A permeability into cell, interaction with calf thymus DNA (ct-DNA), and antitumor activity against HeLa and P388 cells were studied., Apr. 1997, Bioorganic and Medicinal Chemistry Letters, 7 (8), 1083 - 1086, doi;scopus;scopus_citedby

    Scientific journal

  • Stereospecific redox reaction directed by a sulfinyl group

    N Yamazaki; M Okamura; Y Kawai; Y Mikata; A Ohno

    Stereochemistry of reductions of a pyridinium and quinoliniums with an asymmetric sulfinyl group has been studied. Dithionite and borohydride prefer the face characterized by a lone pair on sulfur atom. Dihydropyridine prefers the face characterized by a S-O bond., GORDON BREACH SCI PUBL LTD, 1997, PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS, 120, 445 - 446, web_of_science

    Scientific journal

  • Synthesis and Reaction of NAD(P)H Model Compounds with Interconversion of Central and Axial Chirality

    Yuji Mikata

    In the reaction related to NAD(P)H and its model compound, it has been reported that orientation of carbamoyl moiety in the nicotinamide ring of the coenzyme plays one of the crucial role to determine the stereochemistry of the reaction. In the oxidation of 3-(N-methyl-AT-α-methylbenzylcarbarnoyl)-1,2,4-trimethyl-1,4- dihydroquinoline(Me3MQPH), the stereochemistry of the product, 3-(N-methylAT-α-methylbenzylcarbamoyl)-1, 2, 4-trimethylquinolinium ion(Me3MQP+), is influenced largely by the reactivity of the reagent employed (oxidation potential of the quinone or pKa of the amine). This interesting phenomenon has been interpreted in terms of the differences in stabilities of the two conformations concerning to the carbonyl rotation at the transition-state. The energy difference between the two conformations at the transition-state has been estimated from the temperature dependency of the product ratio. We also studied the conformational analysis of Me3MQPH, the ground -state itself, by means of the dynamic NMR technique. The contribution of the ground-state conformation and role of magnesium ion, which is used as a catalyst, are discussed., 1997, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 55 (2), 132 - 141, doi;scopus;scopus_citedby

    Scientific journal

  • Stereospecific redox reaction directed by a sulfinyl group

    Norimasa Yamazaki; Mutsuo Okamura; Yasushi Kawai; Yuji Mikata; Atsuyoshi Ohno

    Stereochemistry of reductions of a pyridinium and quinoliniums with an asymmetric sulfinyl group has been studied. Dithionite and borohydride prefer the face characterized by a lone pair on sulfur atom. Dihydropyridine prefers the face characterized by a S-O bond., 1997, Phosphorus, Sulfur and Silicon and Related Elements, 120-121, 445 - 446, doi;scopus;scopus_citedby

    Scientific journal

  • Structure of diethyl(2-pyridyl)boranes: Rigid cyclic dimers

    Toshihiro Murafuji; Ryota Mouri; Yoshikazu Sugihara; Katsuto Takakura; Yuji Mikata; Shigenobu Yano

    Diethyl(2-pyridyl)boranes (2a, 2b) comprise cyclic dimers via intermolecular boron-nitrogen coordination bonds. The boron atoms of diethyl[2-(5-methylpyridyl)]borane (2b) show clear pyramidalization. The high tetrahedral character of these boron atoms in 2b indicates that the dimer is far more rigid compared with the tetramer composed of diethyl(3-pyridyl)borane(1a)., 28 Oct. 1996, Tetrahedron, 52 (44), 13933 - 13938, doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)+-NAD(P)H Models. 87. Nonsteric Stereochemistry Controlled by a Carbonyl Dipole

    Atsuyoshi Ohno; Akihiro Tsutsumi; Norimasa Yamazaki; Mutsuo Okamura; Yuji Mikata; Masayuki Fujii

    6,7-Dihydro-1,6,11-trimethyl-5-oxo-5H-benzo[c]pyrido[2,3-e]azepin-1-ium iodide (11-Me-MMPA+I-) was synthesized, and it was confirmed that the axial chirality in the salt is stable at room temperature. Upon the reduction of 11-Me-MMPA+ with a pair of diastereomeric dihydropyridine derivatives, the reacting face is always that in which the carbonyl dipole in the cation is included (i.e., syn selectivity), regardless the configuration of the reducing agent. A steric hindrance, in a classical sense, and other factors contribute to the stereochemistry of the reaction only in a minor part. Plausible intermolecular arrangements at the transition state of the reaction are discussed in order to understand the mechanism of this nonsteric stereochemistry., CHEMICAL SOC JAPAN, Jun. 1996, Bulletin of the Chemical Society of Japan, 69 (6), 1679 - 1685, web_of_science;doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)+-NAD(P)H Models. 86. Nonsteric Stereochemistry in Hydride-Transfer to Sulfinylpyridinium Ion

    Atsuyoshi Ohno; Norimasa Yamazaki; Mutsuo Okamura; Yasushi Kawai; Akihiro Tsutsumi; Yuji Mikata; Masayuki Fujii

    The molecular structure of an enantiomer of nicotinamide coenzyme analog 1 has been determined by X-ray crystallography with the absolute configuration being established by the anomalous dispersion effects of all non-hydrogen atoms: (+)-1 exhibits (S)-form sticking the sulfinyl S-O out of the re face. The stereochemistry of the hydride-transfer reaction between the chiral coenzyme analogs, 1 and MenPNPH, was studied. The hydride from (S)- or (R)-MenPNPH, respectively, transfers to (S)- or (R)-1, affording the dihydropyridine compound syn-2 predominantly: That is, the reaction takes place in the face occupied by the sulfinyl oxygen. On the other hand, the transfer to (R)- or (S)-1 mainly takes place so as to afford anti-2. It has been deduced that (S)-1 reacts with (S)-MenPNPH more than twice as fast as (R)-1 does or vice versa. It has also been elucidated that the amide oxygen in MenPNPH points to 1 exclusively at the transition state of the reaction, regardless the configuration of the reagents. The intermolecular arrangement at the transition state of the reaction is discussed., CHEMICAL SOC JAPAN, Apr. 1996, Bulletin of the Chemical Society of Japan, 69 (4), 1093 - 1098, web_of_science;doi;scopus;scopus_citedby

    Scientific journal

  • A possible origin of newly-born bacterial genes: Significance of GC-rich nonstop frame on antisense strand

    Kenji Ikehara; Fumiko Amada; Shigeko Yoshida; Yuji Mikata; Akira Tanaka

    Base compositions were examined at every position in codons of more than 50 genes from taxonomically different bacteria and of the corresponding antisense sequences on the bacterial genes. We propose that the nonstop frame on antisense strand [NSF(a)] of GC-rich bacterial genes is the most promising sequence for newly-born genes. Reasons are: (i) NSF(a) frequently appears on the antisense strand of GC-rich bacterial genes; (ii) base compositions at three positions in the codon are nearly symmetrical between the gene having around 55% GC content and the corresponding NSF(a); (iii) amino acid compositions of actual proteins are also similar to those of hypothetical proteins from the GC-rich NSF(a); and (iv) proteins from NSF(a) of 60% or more GC content are flexible enough to adapt to various molecules encountered as novel substrates, due to the high glycine content. To support our proposition, using a computer we generated hypothetical antisense sequences with the same base compositions as of NSF(a) at each base position in the codon, and examined properties of resulting proteins encoded by the imaginary genes, It was confirmed that NSF(a) of CC-rich gene carrying about 60% GC content is competent enough for a newly-born gene., 1996, Nucleic Acids Research, 24 (21), 4249 - 4255, doi;pubmed;scopus;scopus_citedby

    Scientific journal

  • Synthesis and evaluation of nitro 5-deazaflavins as novel bioreductive antitumor agents

    Tetsuji Kawamoto; Yoshihiro Ikeuchi; Junko Hiraki; Yoshiteru Eikyu; Kazue Shimizu; Masaki Tomishima; Kiyoshi Bessho; Fumio Yoneda; Yuji Mikata; Mamiko Nishida; Kenji Ikehara; Takuma Sasaki

    A series of nitro 5-deazaflavins, 5-deazaflavins possessing a nitro group at C(6)-C(9) position, has been designed and synthesized as a novel class of bioreductive nitrohetero-aromatic compounds and their cytotoxicities towards L1210 and KB cells were evaluated. It has been found that the nitro 5-deazaflavins undergo one electron reduction on the nitro group and undergo two electrons or "(net) hydride" reduction on the C(5)-C(4a)-C(10a)-N(1) redox system. They showed much more potent antitumor activities than the other 5-deazaflavins bearing no nitro group. These results suggest that an activation of nitro group by biological one electron reduction is crucial for an expression of cytotoxicity. © 1995., 21 Sep. 1995, Bioorganic and Medicinal Chemistry Letters, 5 (18), 2109 - 2114, doi;scopus;scopus_citedby

    Scientific journal

  • Evaluation of differential hypoxic cytotoxicity and electrochemical studies of nitro 5-deazaflavins

    Tetsuji Kawamoto; Yoshihiro Ikeuchi; Junko Hiraki; Yoshiteru Eikyu; Kazue Shimizu; Masaki Tomishima; Kiyoshi Bessho; Fumio Yoneda; Yuji Mikata; Mamiko Nishida; Kenji Ikehara

    Cytotoxicities of nitro 5-deazaflavins were evaluated in vitro towards hypoxic and oxic Chinese hamster cells (V79). 6-Nitro and 8-nitro derivatives were generally more toxic towards hypoxic cells than oxic cells, showing marked hypoxic selectivity. In contrast, 7-nitro and 9-nitro derivatives showed no significant hypoxic selectivity. Electrochemical study using cyclic voltammetry (CV) revealed that 6-nitro and 8-nitro derivatives generate a stable two electrons reduction product as well as a stable one electron reduction product and that 7-nitro and 9-nitro derivatives afford an unstable one electron reduction product. These results strongly support that not solely electron affinity but also stability of the one electron reduction products is crucial for the differential hypoxic cytotoxicities of nitro 5-deazaflavins. © 1995., 21 Sep. 1995, Bioorganic and Medicinal Chemistry Letters, 5 (18), 2115 - 2118, doi;scopus;scopus_citedby

    Scientific journal

  • The enzyme/coenzyme/metal/substrate quaternary complex generated in the transition state of the reduction of benzoylformate with NAD(P)H models

    Yuji Mikata; Kiyoko Mizukami; Kenji Ikehara; Atsuyoshi Ohno

    Enantioselectivities in the reduction of methyl benzoylformate with NAD(P)H model compounds, N-α-methylbenzyl-1-propyl-1,4-dihydronicotinamide (PNPH) and N-benzyl-1-propyl-1,4-dihydronicotinamide (PNBH), in the presence of N-protected amino acids have been studied. The stereoselectivity was perturbed by the amino acids which have a side chain capable of coordinating onto Mg2+. © 1995., 04 Sep. 1995, Tetrahedron Letters, 36 (36), 6491 - 6494, doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)+–NAD(P)H models. 84. Stereochemistry controlled by the electronic effect from a sulfinyl group

    Atsuyoshi Ohno; Norimasa Yamazaki; Akihiro Tsutsumi; Yuji Mikata; Mutsuo Okamura

    2,3‐Dihydro‐2,2,4‐trimethylthieno[3,2‐b]pyridinium 1‐oxide iodide (1) has been reacted with various inorganic and organic hydride donors. It has been found that the stereochemistry of reaction is controlled by the orientation of the sulfinyl dipole, and the relative bulkiness of substituents plays no role in determining the reaction face: a reactive hydride donor prefers to attack at the anti‐face with respect to the sulfinyl dipole, whereas a less reactive hydride donor prefers to attack at the syn‐face. Copyright © 1995 VCH Publishers, Inc., 1995, Heteroatom Chemistry, 6 (1), 51 - 56, doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P+/NAD(P)H Models. 83. Molecular Asymmetry with a Carbonyl Group: Electronically Controlled Stereochemistry in the Reaction of NAD(P)+/NAD(P)H Analogs

    Atsuyoshi Ohno; Akihiro Tsutsumi; Yasushi Kawai; Norimasa Yamazaki; Yuji Mikata; Mutsuo Okamura

    The N-methylpyridiniumsalt of 6,7-dihydro-6-methyl-5-oxopyridino[3,2-d]-2-benzazepin has been synthesized. The salt has axial chirality with respect to the orientation of the carbonyl dipole. An enantiomer of the cation has been obtained as the iodide salt. Reduction of the salt results in the corresponding dihydropyridine derivative stereospecifically. The stereochemistry of the reduction is controlled entirely by the electronic effect of the carbonyl dipole. © 1994, American Chemical Society. All rights reserved., 01 Sep. 1994, Journal of the American Chemical Society, 116 (18), 8133 - 8137, doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)+-NAD(P)H MODELS .81. TEMPERATURE-DEPENDENT STEREOSPECIFICITY IN THE INTERCONVERSION BETWEEN CENTRAL AND AXIAL CHIRALITIES

    M OKAMURA; Y MIKATA; N YAMAZAKI; A TSUTSUMI; A OHNO

    In the oxidation of (4R)-Me3MQPH or (4R)-Me3PNPH with a series of 1,4-benzoquinone and its derivatives, the R/S ratio with respect to the axial chirality in the product, i.e., 11R-/11S- isomer ratio in Me3MQP+ or 7R-/7S- isomer ratio in Me3PNP+, changes depending on the reaction temperature as well as the reactivity of quinone. It is confirmed that kinetic R-preference stems from the entropy-control, whereas kinetic S-preference comes out of the enthalpy-control. The relative importance of enthalpy and entropy is discussed in terms of the earliness and lateness of the transition state at the initial electron-transfer step., CHEMICAL SOC JAPAN, Apr. 1993, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 66 (4), 1191 - 1196, web_of_science

    Scientific journal

  • NAD(P)+-NAD(P)H MODELS .82. EFFECT OF MAGNESIUM-ION ON THE STEREOSPECIFICITY AND CONFORMATIONS AT THE GROUND AND TRANSITION-STATES OF THE REACTION

    M OKAMURA; Y MIKATA; N YAMAZAKI; A TSUTSUMI; A OHNO

    Conformations of 3-[methyl(alpha-methylbenzyl)carbamoyl]-1,2,4-trimethyl-1,4-dihydroquinoline ((4R)-Me3MQPH) in the presence and absence of magnesium ion have been studied. The major conformation at the ground state of Me3MQPH changes largely when this molecule forms a complex with a magnesium ion. The conformations at the ground and transition states will be discussed in relation to the stereospecificity of the reaction of this compound with quinones., CHEMICAL SOC JAPAN, Apr. 1993, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 66 (4), 1197 - 1203, web_of_science

    Scientific journal

  • NAD(P)H-NAD(P)+MODELS .77. STEREOSPECIFIC ELECTROCHEMICAL OXIDATION OF NAD(P)H ANALOGS MEDIATED BY RADICAL CATION OF ANILINES

    M OKAMURA; T KASHIWAGI; Y MIKATA; N YAMAZAKI; A OHNO

    Net hydrogen-atom (H.) transfer was observed in electrochemical oxidation of NAD(P)H analogs in the presence of aniline or its derivatives. The reaction mechanism is discussed on the basis of stereospecificities., CHEMICAL SOC JAPAN, Jul. 1992, CHEMISTRY LETTERS, (7), 1247 - 1250, web_of_science

    Scientific journal

  • Stereospecificity observed in base-catalyzed electrochemical oxidation

    Mutsuo Okamura; Takeshi Kashiwagi; Yuji Mikata; Tetsushi Maruyama; Atsuyoshi Ohno

    A mechanism for amine-catalysis of stereospecificity in electrochemical oxidation of (4R)-Me3 MQPH and (4R)-Me3PNPH is discussed. © 1991., 11 Mar. 1991, Tetrahedron Letters, 32 (11), 1475 - 1478, doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)H-NAD(P)+ models. 73. Structure-stereochemistry relationship in the reaction of NAD analog

    Atsuyoshi Ohno; Yuji Mikata; Mutsuo Goto; Takeshi Kashiwagi; Takanori Tanaka; Masami Sawada

    © 1991 The Chemical Society of Japan. Four different NAD(P)H analogs have been oxidized by various substituted and unsubstituted 1,4-benzoquinones in the presence or absence of magnesium ion. The stereospecificity of the reaction depends not only on the reactivity of quinone but also on that of the analogs as well as on the presence or absence of magnesium ion. The results are discussed from the viewpoint of reaction mechanism for the transfer of a (net) hydride ion., Jan. 1991, Bulletin of the Chemical Society of Japan, 64 (1), 81 - 86, doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)H-NAD(P)+ models. 74. Entropy-controlled kinetics, stereochemistry, and tunneling effect

    Atsuyoshi Ohno; Mutsuo Goto; Yuji Mikata; Takeshi Kashiwagi; Tetsushi Maruyama

    © 1991 The Chemical Society of Japan. Kinetics have been studied for the reactions of three NAD(P)H analogs and their 4-deuteriated compounds with 2,6-dichloro- and tetrachloro-l,4-benzoquinones. It has been elucidated that the entropy term occupies 50-90% of the Gibbs energy of activation at 298 K. Thus, the reaction is almost entropy-controlled. For certain combinations of the reducing and oxidizing reagents, quantum mechanical tunneling effect plays a large role to determine the reaction rate. The tunneling effect may be another measure of the stereochemistry., Jan. 1991, Bulletin of the Chemical Society of Japan, 64 (1), 87 - 90, doi;scopus;scopus_citedby

    Scientific journal

  • NAD (P)+-NAD (P)H models. 69. Mechanism of stereospecific (NET) hydride transfer controlled by electronic effect

    A. Ohno; M. Ogawa; Y. Mikata; M. Goto

    CHEMICAL SOC JAPAN, 1990, Bulletin of the Chemical Society of Japan, 63 (3), 813 - 818, web_of_science;doi;scopus;scopus_citedby

    Scientific journal

  • NAD(P)+-NAD(P)H models. 72. Isotope effects to prove the multi-step mechanism in the reduction with an NAD(P)H analog

    M. Goto; Y. Mikata; A. Ohno

    CHEMICAL SOC JAPAN, 1990, Bulletin of the Chemical Society of Japan, 63 (9), 2682 - 2686, web_of_science;doi;scopus;scopus_citedby

    Scientific journal

  • Asymmetric reduction of ketones with microbes

    K. Nakamura; Y. Kawai; T. Kitayama; T. Miyai; M. Ogawa; Y. Mikata; M. Higaki; A. Ohno

    1989, Bull. Int. Chem. Res. Kyoto Univ, 67(3), 157-168 (3), 157 - 168

  • High Pressure Mediated Diels-Aider Reaction of Furan With Dialkyl (Acetoxymethylene)Malonate

    Akira Sera; Meguru Ohara; Toshiaki Kubo; Kuniaki Itoh; Hiroaki Yamada; Yuji Mikata; Chikara Kaneko; Nobuya Katagiri

    The Diels-AIder reaction of furan with dialkyl (acetoxymethylene)malonates 1 did not proceed even in the presence of Lewis acid catalysts under conventional conditions. However, the reaction under high pressure(1.1 GPa) gave the expected cycloadducts, dialkyl 3-acetoxy-7-oxabicyclo[2.2.1]hept-5-ene-2,2-dicarboxylates 2. The bis-, tris-, and tetrakisadducts 3-6 were also produced insome amounts. Similar high-pressure reactions in the presence of zinc iodide as a catal st yielded dialkyl2-furfurylidenemalonate 8, and noneof the adducts were obtained. © 1988, American Chemical Society. All rights reserved., 01 Nov. 1988, Journal of Organic Chemistry, 53 (23), 5460 - 5464, doi;scopus;scopus_citedby

    Scientific journal

  • Inter-and Intramolecular Cycloaddition Reactions of Ethenetricarboxylates with Styrenes and Halostyrenes

    Shoko Yamazaki; Zhichao Wang; Kentaro Iwata; Khotaro Katayama; Hirotaka Sugiura; Yuji Mikata; Tsumoru Morimoto; Akiya Ogawa

    © 2021 BMJ Publishing Group. All rights reserved. Inter-and intramolecular cycloaddition reactions of ethenetricarboxylates with styrenes and α-halostyrenes have been investigated. The reactions of ethenetricarboxylates with styrenes or α-bromostyrenes in the presence of SnCl 4or SnBr 4stereoselectively gave 2,4-cis-substituted cyclobutanes. The intramolecular cycloaddition reactions of a series of styrene-functionalized ethenetricarboxylate amides, including in situ generated derivatives, showed high diversity of reaction modes depending on the structures and substituents of the substrates. The regioselectivity and stereoselectivity of the reactions as well as reaction mechanisms were discussed based on the DFT calculations., GEORG THIEME VERLAG KG, 16 Feb. 2021, Synthesis (Germany), 53 (4), 731 - 753, doi;web_of_science;scopus;scopus_citedby

    Scientific journal

  • N,N,N′,N′-Tetrakis(3-isoquinolylmethyl)-2,6-lutidylenediamine (3-isoTQLN): A Fluorescent Zn2+/Cd2+ Dual Sensor as a Hybrid of 2-Quinolyl/1-Isoquionolyl Counterparts TQLN/1-isoTQLN

    Yuji Mikata; Ayaka Takekoshi; Minori Kaneda; Shizuka Yonemura; Yuri Aono; Arimasa Matsumoto; Hideo Konno; Shawn C. Burdette

    Fluorescence detection of Zn and Cd is of continuing interest due to their significant importance in biological and environmental sciences. Strict discrimination of Zn and Cd by fluorescent probe molecules has still been a challenging task because of the small difference in ionic radii of these group 12 metal ions. In this study, three heptadentate fluorescent probes with a common 2,6-lutidylenediamine core and four quinoline/isoquinoline sidearms are presented. The N,N,N′,N′-tetrakis(2-quinolylmethyl)-2,6-lutidylenediamine (TQLN) exhibits Zn -specific fluorescence enhancement via an excimer formation, while the N,N,N′,N′-tetrakis(1-isoquinolylmethyl)-2,6-lutidylenediamine (1-isoTQLN) responds specifically to Cd at the short wavelength region by monomer emission. The N,N,N′,N′-tetrakis(3-isoquinolylmethyl)-2,6-lutidylenediamine (3-isoTQLN) responds to both Zn and Cd at different emission wavelengths, acting as a dual sensor with hybrid properties of TQLN and 1-isoTQLN. Methoxy-substituted derivatives of 1- and 3-isoTQLN were also examined. 2+ 2+ 2+ 2+ 2+ 2+ 2+ 2+, 2021, European Journal of Inorganic Chemistry, (13), 1287 - 1296, doi;scopus;scopus_citedby

    Scientific journal

  • Structure and electrochemical properties of (μ-O)2Mn2(iii,iii) and (μ-O)2Mn2(iii,iv) complexes supported by pyridine-, quinoline-, isoquinoline- And quinoxaline-based tetranitrogen ligands

    Yuji Mikata; Yasuko Kuroda; Kyoko Naito; Kana Murakami; Chihiro Yamamoto; Shoko Yabe; Shizuka Yonemura; Arimasa Matsumoto; Hajime Katano

    Seven new bis(μ-oxo)dimanganese complexes with Mn (iii,iii) or Mn (iii,iv) oxidation states were prepared using quinoline- and isoquinoline-based tetraamine ligands. The structures of the ligands include ethylenediamine,trans-1,2-cyclohexanediamine and tripodal amine, bearing two or three nitrogen-containing heteroaromatics. Regardless of the skeleton and number of aliphatic nitrogen atoms in the ligands, quinoline complexes stabilize the Mn (iii,iii) oxidation state, whereas, isoquinoline ligands afford Mn (iii,iv) complexes. A systematic comparison of the differences in structural parameters and redox potentials of a total of 14 complexes with a (μ-O) Mn diamond core, which includes corresponding pyridine and quinoxaline derivatives as supporting ligands, highlights the distinct deviation of quinoline and tripodal amine motifs in this ligand series. 2 2 2 2 2 2, 28 Mar. 2021, Dalton Transactions, 50 (12), 4133 - 4144, True, doi;pubmed;scopus;scopus_citedby

    Scientific journal

MISC

  • サイエンス・オープンラボを通した化学(電池の歴史、化学発光)学習ー大学生による演示実験を動機付けにした高等学校授業開発研究ー

    TAKASHIMA Hiroshi; TAKEUCHI Takae; MIKATA Yuji; URA Yasuyuki; NAKAJIMA Takayuki; MATSUURA Noriyuki

    Mar. 2019, 教育システム研究, (14), 103 - 111

  • サイエンス・オープンラボを通した化学(有機合成、酸化還元、界面活性剤)学習ー大学生による演示実験を動機付けにした高等学校授業開発研究ー

    MIKATA Yuji; TAKEUCHI Takae; TAKASHIMA Hiroshi; MATSUURA Noriyuki; HASE

    Mar. 2018, 教育システム研究, (13), 429 - 436

  • C‐グリコシルβ‐アミノ酸を用いたβ‐ペプチドの合成と立体構造解析

    稲葉陽子; 矢野重信; 中沢隆; 川上徹; 相本三郎; 池上貴久; 三方裕司

    10 Sep. 2007, 生体機能関連化学シンポジウム講演要旨集, 22nd, 182 - 183, j_global;url

  • C‐グリコシド結合を有するβ‐アラニン型糖アミノ酸を用いた糖ペプチドの合成と立体構造解析

    稲葉陽子; 矢野重信; 中沢隆; 川上徹; 相本三郎; 池上貴久; 三方裕司

    12 Mar. 2007, 日本化学会講演予稿集, 87th (2), 1346, j_global;url

  • Unprecedented sugar-dependent in vivo antitumor activity of carbohydrate-pendant cis-diamminedichloroplatinum(II) complexes

    S Yano; Y Shinohara; Brudzinska, I; Y Mikata; C Orvig

    ELSEVIER SCIENCE INC, Aug. 2001, JOURNAL OF INORGANIC BIOCHEMISTRY, 86 (1), 486 - 486, web_of_science

    Summary international conference

  • Development of sugar-linked bacteriochlorin derivatives for photodynamic therapy

    S Hirohara; Y Onchi; Y Sugai; Y Mikata; Okura, I; S Ogura; Kinoshita, I; T Kakuchi; S Yano

    ELSEVIER SCIENCE INC, Aug. 2001, JOURNAL OF INORGANIC BIOCHEMISTRY, 86 (1), 263 - 263, web_of_science

    Summary international conference

  • Acid-base and metal ion-binding properties of diaminopropyl D-glucopyranoside and diaminopropyl D-mannopyranoside compounds in aqueous solution

    SONG B; MEHRKHODAVANDI P; BUGLYO P; MIKATA Y; SHINOHARA Y; YONEDA K; YANO S; ORVIG C

    2000, J. Chem. Soc. Dalton Trans., (8), 1325 - 1333, doi;cinii_articles

  • Acid-base and metal ion-binding properties of (2S)-2,3-diaminopropyl beta-D-glucopyranoside (1-beta-D-Glc-pn) in aqueous solution

    B Song; Y Mikata; Y Shinohara; K Yoneda; S Yano; C Orvig

    ELSEVIER SCIENCE INC, Apr. 1999, JOURNAL OF INORGANIC BIOCHEMISTRY, 74 (1-4), 300 - 300, web_of_science

    Summary international conference

  • Synthesis of new glycosylated porphyrins and it's photoreduction to chlorin derivatives by ascorbic acid.

    M Shibata; T Kakuchi; T Takemura; Y Mikata; S Yano

    AMER CHEMICAL SOC, Aug. 1998, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 216, U690 - U690, web_of_science

    Summary international conference

Books etc

  • “Metal-Carbohydrate Interactions/Complexes,” in “Encyclopedia of Inorganic and Bioinorganic Chemistry”

    MIKATA Yuji (, Range: 筆頭著者)

    Wiley, Jun. 2017

  • Metal complexes of carbohydrate-targeted ligands in medicinal inorganic chemistry

    MIKATA Yuji; Michael Gottschaldt (, Range: 筆頭著者)

    Wiley, 2014, 145-173

Presentations

  • テトラキスキノリン部位を有する窒素八座配位子の亜鉛およびカドミウムイオンに対する蛍光応答

    登坂菜生; 櫻井優衣; 松本有正; 三方裕司

    日本化学会第100春季年会, Mar. 2020, Mar. 2020

  • Cadmium ion-specific fluorescent response of a TQEN-based oxygen-containing octadentate ligand

    A. Tsuruta; M. Kaneda; A. Matsumoto; Y. Mikata

    日本化学会第100春季年会, Mar. 2020

  • Synthesis and structure of metal complexes with an asymmetric ether oxygen atom coordinated to the metal center

    M. Uchida; A. Matsumoto; Y. Mikata

    日本化学会第100春季年会, Mar. 2020

  • ベンゾフェノン誘導体のキラル-アキラル結晶多形およびその制御

    黒﨑瑞穂; 松本有正; 平田修造; 三方裕司

    日本化学会第100春季年会, Mar. 2020

  • TPA骨格を有するイソキノリン誘導体を配位子として用いた鉄二核錯体の構造と性質

    . 山本千尋; 中山広実; 青野有理; 松本有正; 三方裕司

    第52回酸化反応討論会, 09 Nov. 2019, 10 Nov. 2019

  • Cadmium-Specific Fluorescent Sensors with Polyquinoline Structures

    Y. Mikata

    ACCC7, 15 Oct. 2019, 18 Oct. 2019

  • テトラキスキノリン部位を有する窒素八座配位子の金属イオンに対する蛍光応答

    登坂菜生; 櫻井優衣; 松本有正; 三方裕司

    第69回錯体化学会討論会, 21 Sep. 2019, 23 Sep. 2019

  • TPA骨格を有するイソキノリン誘導体を配位子として用いた鉄二核錯体によるアルカンの酸化反応

    山本千尋; 中山広実; 青野有理; 松本有正; 三方裕司

    第69回錯体化学会討論会, 21 Sep. 2019, 23 Sep. 2019

  • ベンゾフェノン誘導体のキラル結晶化とその多形制御

    黒﨑瑞穂; 松本有正; 三方裕司

    モレキュラー・キラリティーシンポジウム, 14 Jun. 2019, 15 Jun. 2019

  • キノリルアルカノールの不斉自己触媒反応の検討

    秋月美澄; 田中綾芽; 松本有正; 三方裕司

    モレキュラー・キラリティーシンポジウム, 14 Jun. 2019, 15 Jun. 2019

  • 円二色性スペクトルによる不斉自己触媒反応におけるピリミジルアルカノール亜鉛アルコキシド会合体の解析

    田中綾芽; 松本有正; 三方裕司

    モレキュラー・キラリティーシンポジウム2019, 14 Jun. 2019, 15 Jun. 2019

  • Structure and Properties of High Valent Diiron Complexes Using Isoquinoline-Based Ligands Derived from TPA

    C. Yamamoto; Y. Aono; H. Nakayama; A. Matsumoto; Y. Mikata

    ISABC15, 02 Jun. 2019, 05 Jun. 2019

  • Zn2+/Cd2+-Selective Fluorescent Response of Quinoline-Based Ligands with Piperzine and Homopiperazine Frameworks

    M. Tanaka; Y. Nodomi; A. Matsumoto; Y. Mikata

    ISABC15, 02 Jun. 2019, 05 Jun. 2019

  • TPA骨格を有するイソキノリン誘導体を配位子として用いた鉄二核錯体の構造と反応性

    MIKATA Yuji

    日本化学会第99春季年会, Mar. 2019

  • 立体規制を導入したテトラキスキノリン誘導体による亜鉛イオンとカドミウムイオンの識別

    MIKATA Yuji

    日本化学会第99春季年会, Mar. 2019

  • 円二色性スペクトルによる不斉自己触媒反応の活性種の検討

    MIKATA Yuji

    日本化学会第99春季年会, Mar. 2019

  • Fluorescent detection of Intracellular cadmium ion by carbohydrate-pendant polyquinoline ligands

    MIKATA Yuji; Yuji Mikata

    AsBIC9, Dec. 2018

  • Cadmium-Specific Intramolecular Excimer Formation in TQEN Derivatives with Heptadentate Structure

    MIKATA Yuji; Yuji Mikata

    ICCC2018, Aug. 2018

  • Carbohydrate-Appended, Quinoline-Based Ligands for Fluorescent Detection of Intracellular Cadmium Ion

    MIKATA Yuji; Yuji Mikata

    Gordon Research Conference- Metals in Medicine, Jul. 2018

  • 2,6-ルチジレンジアミン骨格を有するキノリンおよびイソキノリン誘導体を用いたカドミウムと亜鉛の特異的蛍光識別

    MIKATA Yuji

    第68回錯体化学会討論会, Jul. 2018

  • 糖連結テトラキスキノリン誘導体による細胞内カドミウムイオンの蛍光検出

    MIKATA Yuji

    第16回ホスト-ゲスト・超分子化学シンポジウム, Jun. 2018

  • キノリン類縁体を含む配位子を用いたマンガン二核錯体の合成とその特性

    MIKATA Yuji

    日本化学会第98春季年会, Mar. 2018

  • Synthesis and Reactivity of Cobalt Complexes with Isoquinoline-Based Ligands Derived from TPA

    MIKATA Yuji; Tomoko Ishii; Arimasa Matsumoto; Yuji Mikata

    The Chemical Society of Japan 98th Annual Spring Congress, Mar. 2018

  • キレート配位子BAPTAを基本骨格とするテトラキスキノリン誘導体のカドミウム特異的蛍光応答

    MIKATA Yuji

    日本化学会第98春季年会, Mar. 2018

  • キレート配位子EGTAおよびBAPTAを基本骨格とするテトラキスキノリン誘導体のカドミウム特異的蛍光応答

    MIKATA Yuji

    第67回錯体化学会討論会, Sep. 2017

  • イソキノリン部位を有するエチレンジアミン誘導体を用いたオキソ架橋を含む鉄二核錯体の構造と反応

    MIKATA Yuji

    第67回錯体化学会討論会, Sep. 2017

  • イソキノリン部位を有するTPA誘導体を用いたオキソ架橋を含む鉄二核錯体の構造と反応

    MIKATA Yuji

    第67回錯体化学会討論会, Sep. 2017

  • Structure of Zinc Alkoxide Complexes in Asymmetric Autocatalysis of Pyrimidyl Alkanol

    MIKATA Yuji; Arimasa Matsumoto; Misumi Akizuki; Ayame Tanaka; Yuji Mikata; Tsuneomi Kawasaki; Kenso Soai

    67th JSCC Conference, Sep. 2017

  • テトラキスキノリン誘導体の金属イオン特異的蛍光応答

    MIKATA Yuji

    第15回ホスト-ゲスト・超分子化学シンポジウム, Jun. 2017

  • Fluorescent Response of Substituted Tetrakisquinoline and Phenanthridine Derivatives toward Pyrophosphate Ion

    MIKATA Yuji; Risa Nishijima; Risa Ohnishi; Yuji Mikata

    The Chemical Society of Japan 97th Annual Spring Congress, Mar. 2017

  • キノリン及びイソキノリン部位を有する蛍光性七座配位子による亜鉛とカドミウムの識別

    MIKATA Yuji

    日本化学会第97春季年会, Mar. 2017

  • Molecular Design of Cadmium-Specific Fluorescent Sensors

    MIKATA Yuji; Y. Mikata; M. Kaneda; A. Kizu

    AsBIC8, Dec. 2016

  • Quinoline-Based Molecular Design of Cd2+-Specific Fluorescent Probes

    MIKATA Yuji; Y. Mikata; M. Kaneda; A. Kizu

    SPACC23, Nov. 2016

  • TPA骨格を持つイソキノリン誘導体を配位子として用いた鉄二核錯体の構造とその安定性

    MIKATA Yuji

    第66回錯体化学討論会, Sep. 2016

  • キノリン部位を有する糖含有カドミウム特異的蛍光センサーの開発

    MIKATA Yuji

    第66回錯体化学討論会, Sep. 2016

  • テトラキスキノリン誘導体のカドミウムイオン選択的蛍光応答

    MIKATA Yuji

    第14回ホスト・ゲスト化学シンポジウム, Jun. 2016

  • TPA骨格を持つイソキノリン誘導体を配位子として用いた鉄二核錯体の合成とその構造

    MIKATA Yuji

    日本化学会第96春季年会, Mar. 2016

  • キノリンおよびキノキサリン部位を有する配位力の異なるリガンドを用いたマンガン二核錯体の構造と特性

    MIKATA Yuji

    日本化学会第96春季年会, Mar. 2016

  • Mechanism for Specific Response of TQEN-Based Heptadentate Ligands toward Cadmium Ion

    MIKATA Yuji; Asako Kizu; Yuji Mikata

    The Chemical Society of Japan 96th Annual Spring Congress, Mar. 2016

  • 糖含有TQEN誘導体のカドミウム特異的蛍光応答

    MIKATA Yuji

    日本化学会第96春季年会, Mar. 2016

  • Quinoline-based ligand design for fluorescent sensing of metal ions

    MIKATA Yuji; Yuji Mikata

    Pacifichem2015, Dec. 2015

  • キノリンおよびキノキサリン誘導体を配位子として用いたマンガン二核錯体の合成とその特性

    MIKATA Yuji

    第48回酸化反応討論会, Oct. 2015

  • テトラキスキノリン誘導体のカドミウムイオン特異的蛍光応答

    MIKATA Yuji

    第48回酸化反応討論会, Oct. 2015

  • キノリン部位を有する亜鉛二核錯体を用いたピロリン酸イオン及びリン酸イオンの検出

    MIKATA Yuji

    第65回錯体化学討論会, Sep. 2015

  • TQENを基本骨格とした七座配位子のカドミウム特異的蛍光応答

    MIKATA Yuji

    第65回錯体化学討論会, Sep. 2015

  • TQEN誘導体におけるエチレンジアミン部位の立体規制による亜鉛錯体形成時の蛍光挙動変化

    MIKATA Yuji

    第65回錯体化学討論会, Sep. 2015

  • Fluorescent Sensing of Specific Metal Ions with Quinoline-Amine Conjugates

    MIKATA Yuji; Yuji Mikata

    SPACC22, Aug. 2015

  • Quinoline-Based Fluorescent Ligand for Detection of Biological Metal Ions

    MIKATA Yuji; Yuji Mikata

    ICBIC17, Jul. 2015

  • キノリン誘導体のカドミウムイオン特異的蛍光応答

    MIKATA Yuji

    第13回ホスト・ゲスト化学シンポジウム, Jun. 2015

  • TQEN誘導体への立体障害導入による亜鉛錯体形成時の蛍光挙動変化

    MIKATA Yuji

    日本化学会第95春季年会, Mar. 2015

  • キノリン部位を有するアミン誘導体を用いた亜鉛イオン特異的蛍光検出及びリン酸イオンの識別

    MIKATA Yuji

    日本化学会第95春季年会, Mar. 2015

  • エーテル/チオエーテル部位を有するTQEN誘導体のカドミウム特異的蛍光応答

    MIKATA Yuji

    日本化学会第95春季年会, Mar. 2015

  • o-フェニレンジアミンを基本骨格とするキノリン誘導体のカドミウム特異的蛍光応答

    MIKATA Yuji

    第64回錯体化学討論会, Sep. 2014

  • 亜鉛イオンを定量的に検出するイソキノリン型蛍光プローブの開発

    MIKATA Yuji

    第64回錯体化学討論会, Sep. 2014

  • Bis(2-quinolylmethyl)ethylenediaminediacetic acids (BQENDAs), tqen-edta hybrids as fluorescent sensors

    MIKATA Yuji; Y. Mikata; S. Takeuchi; H. Konno; S. Iwatsuki; S. C. Burdette

    ICCC41, Jul. 2014

  • イソキノリン誘導体による亜鉛イオンの定量的蛍光検出

    MIKATA Yuji

    第11回ホスト・ゲスト化学シンポジウム, Jun. 2014

  • キノリン部位を有するトリス(2-ピリジルメチル)アミン(TPA)アナローグの亜鉛イオン選択的蛍光応答

    MIKATA Yuji

    日本化学会第94春季年会, Mar. 2014

  • イソキノリン誘導体を用いた亜鉛イオンの定量的蛍光検出

    MIKATA Yuji

    日本化学会第94春季年会, Mar. 2014

  • 水溶性TQEN誘導体の亜鉛イオンに対する蛍光特性の検証

    MIKATA Yuji

    日本化学会第94春季年会, Mar. 2014

  • キノリン部位を有するo-フェニレンジアミン誘導体のカドミウム特異的蛍光応答

    MIKATA Yuji

    日本化学会第94春季年会, Mar. 2014

  • キノリン部位を有するアミン誘導体のカドミウム選択的蛍光応答

    MIKATA Yuji

    日本化学会第94春季年会, Mar. 2014

  • Quinoline-ligated Dinuclear Zinc Complexes as a Fluorescenr Sensor for Pyrophosphate Anion

    MIKATA Yuji; R. Ohnishi; A. Ugai; Y. Mikata

    The 2nd Japan-France Coordination Chemistry Symposium, Nov. 2013

  • Comparison of Fluorescence Properties of Quinoline-based Ethylenediamine Derivatives toward Zinc and Cadmium Ions

    MIKATA Yuji; S. Takeuchi; Y. Mikata

    The 2nd Japan-France Coordination Chemistry Symposium, Nov. 2013

  • Fluorescent Response of Quinoline-based TACN Derivatives toward Zinc(II)

    MIKATA Yuji; Y. Nodomi; A. Kizu; H. Konno; Y. Mikata

    The 2nd Japan-France Coordination Chemistry Symposium, Nov. 2013

  • Quinoline-based ligand design for fluorescent sensing of metal ions and anions

    MIKATA Yuji; Y. Mikata

    SPACC20, Sep. 2013

  • Quantitative Fluorescence Detection of Pyrophosphate with Quinoline-Ligated Dinuclear Zinc Complexes

    MIKATA Yuji; Y. Mikata

    ICBIC16, Jul. 2013

  • キノリン誘導体を配位子とする亜鉛二核錯体によるピロリン酸の定量蛍光検出

    MIKATA Yuji

    第10回ホスト・ゲスト化学シンポジウム, May 2013

  • 亜鉛イオン選択的蛍光応答を示すキノリンおよびイソキノリン誘導体の金属親和性に関する総合的考察

    MIKATA Yuji

    日本化学会第93春季年会, Mar. 2013

  • キノリン骨格を有する銅二核錯体の構造と反応性

    MIKATA Yuji

    日本化学会第93春季年会, Mar. 2013

  • キノリンおよびイソキノリン部位を有するN,N’-ジメチルエチレンジアミン誘導体を用いたビス(μ-オキソ)マンガン二核錯体の合成とその特性

    MIKATA Yuji

    日本化学会第93春季年会, Mar. 2013

  • キノリン部位を有する亜鉛二核錯体のピロリン酸に対する蛍光応答機構

    MIKATA Yuji

    日本化学会第93春季年会, Mar. 2013

  • キノリン骨格を有するトリス(2-ピリジルメチル)アミン(TPA)類似体の金属イオンに対する蛍光応答

    MIKATA Yuji

    日本化学会第93春季年会, Mar. 2013

  • 中西香織・三方裕司

    MIKATA Yuji

    日本化学会第93春季年会, Mar. 2013

  • Zinc-Specific Fluorescent Response of Quinoline-Based Tripodal Ligands

    MIKATA Yuji; Y. Mikata; K. Kawata

    ICCC40, Sep. 2012

  • 亜鉛イオン特異的蛍光センサーTQENの機能改善

    MIKATA Yuji

    第62回錯体化学討論会, Sep. 2012

  • キノリン部位を有するアミン誘導体の水銀(II)および鉄(III)イオン特異的蛍光応答

    MIKATA Yuji

    第62回錯体化学討論会, Sep. 2012

  • TQEN and isoTQEN Derivatives on 1,2-Cyclohexanediamine Platform as Fluorescent Zinc Sensors with Enhanced Fluorescence and Zn/Cd Selectivity

    MIKATA Yuji; Y. Mikata; Y. Sato; S. Takeuchi; Y. Kuroda

    SPACC19, Aug. 2012

  • Fluorescent Response of Quinoline-Based Ethylenediamine Derivatives toward Zinc Ion in Aqueous Solution

    MIKATA Yuji; S. Takeuchi; Y. Mikata

    SPACC19, Aug. 2012

  • Fluorescent Response of Quinoline-Based Amine Derivatives toward Metal Ion

    MIKATA Yuji; Y. Nodomi; Y. Mikata

    SPACC19, Aug. 2012

  • イソキノリン部位を有するエチレンジアミン誘導体の水中における亜鉛イオン選択的蛍光応答

    MIKATA Yuji

    日本化学会第90春季年会, Mar. 2012

  • 1,4,7-トリアザシクロノナン骨格を有するキノリン誘導体の亜鉛イオン選択的蛍光応答

    MIKATA Yuji

    日本化学会第90春季年会, Mar. 2012

  • Qunoline-Based Fluorescent Zinc Sensor with High Affinity and Selectivity

    MIKATA Yuji; Y. Mikata

    Zing Conference, Dec. 2011

  • キノリン部位を有する水溶性亜鉛イオン蛍光センサーの開発

    MIKATA Yuji

    第61回錯体化学討論会, Sep. 2011

  • イソキノリン部位を有する配位子を用いたマンガン四核錯体の合成

    MIKATA Yuji

    第61回錯体化学討論会, Sep. 2011

  • Cellular Uptake of Rhenium(I) Tricarbonyl Complexes with Carbohydrate Pendant Ligands.

    MIKATA Yuji; Y. Mikata

    SPACC18, Aug. 2011

  • Fluorescent Chemosensor Based on Isoquinoline for Detection for Zinc Ion in Living Cell.

    MIKATA Yuji; K. Kawata; Y. Mikata

    SPACC18, Aug. 2011

  • Fluorescent Characteristics of Water-Soluble, Quinoline-Based Ligand Affected by Zinc Ion.

    MIKATA Yuji; A. Ugai; S. Iwatsuki; Y. Mikata

    SPACC18, Aug. 2011

  • Quinoline-Based Ligand Design for Metal Ion Sensing and Molecular Architecture.

    MIKATA Yuji; Y. Mikata

    ICBIC15, Aug. 2011

  • Quinoline-based fluorescent zinc sensor with glucose pendant.

    MIKATA Yuji; A. Ugai; S. Iwatsuki; Y. Mikata

    ICBIC15, Aug. 2011

  • Isoquinoline-based fluorescent zinc sensor molecules.

    MIKATA Yuji; K. Kawata; Y. Mikata

    ICBIC15, Aug. 2011

  • 複素環芳香族置換グリシン誘導体を配位子とする金属錯体の合成と構造

    MIKATA Yuji

    日本化学会第91春季年会, Mar. 2011

  • キノリン部位を有する糖含有エチレンジアミン誘導体の亜鉛イオン選択的蛍光応答

    MIKATA Yuji

    日本化学会第91春季年会, Mar. 2011

  • Carbohydrate-appended metal complexes for enhanced cellular uptake of metal ion.

    MIKATA Yuji; Y. Mikata; Y. Noguchi; K. Takahashi

    Pacifichem 2010 Congress, Dec. 2010

  • Mercury(II)-selective fluorescent response of bisquinoline derivatives with thioether linkage.

    MIKATA Yuji; Y. Mikata; F. Nakagaki

    Pacifichem 2010 Congress, Dec. 2010

  • Fluorescent response of isoquinoline-based amine derivatives toward zinc ion.

    MIKATA Yuji; K. Kawata; Y. Mikata

    Pacifichem 2010 Congress, Dec. 2010

  • 金属の細胞内導入を目指した糖含有配位子の開発

    MIKATA Yuji

    第60回錯体化学討論会, Sep. 2010

  • 亜鉛イオン特異的蛍光応答を示すトリス(1-イソキノリルメチル)アミン誘導体の開発

    MIKATA Yuji

    第60回錯体化学討論会, Sep. 2010

  • 糖含有配位子を用いた細胞への金属イオン導入

    MIKATA Yuji

    第4回バイオ合同シンポジウム, Sep. 2010

  • 生物学的応用を目的とした糖含有配位子の開発

    MIKATA Yuji

    日本化学会第90春季年会, Mar. 2010

  • キノリン骨格を有するアルカンチオエーテル配位子の水銀(II)イオン選択的蛍光応答

    MIKATA Yuji

    日本化学会第90春季年会, Mar. 2010

  • イソキノリン部位を有するアミン誘導体の亜鉛イオン選択的蛍光応答

    MIKATA Yuji

    日本化学会第90春季年会, Mar. 2010

  • エーテル酸素原子が金属中心に配位した亜鉛錯体の合成と構造

    MIKATA Yuji

    日本化学会第90春季年会, Mar. 2010

  • Quinoline- and isoquinoline-based molecular design for functional metal complexes.

    MIKATA Yuji; Y. Mikata

    17th International SPACC-CSJ Symposium, Oct. 2009

  • 新規糖含有アニオン性配位子を用いた金属錯体の開発

    MIKATA Yuji

    第59回錯体化学討論会, Sep. 2009

  • キノリン骨格を有するチオエーテル配位子の水銀イオンに対する蛍光応答

    MIKATA Yuji

    第59回錯体化学討論会, Sep. 2009

  • The TQEN (Tetrakis(2-quinolylmethylethylenediamine)) Family as Fluorescent Zinc Sensors.

    MIKATA Yuji; Y. Mikata

    PPC 2009, Jul. 2009

  • The Isoquinoline-Based TQEN Family as TPEN-Derived Fluorescent Zinc Sensors.

    MIKATA Yuji; Y. Mikata

    ICBIC14, Jul. 2009

  • Development of Isoquinoline-Based Fluorescent Zinc Sensor with High Affinity.

    MIKATA Yuji; A. Yamashita; Y. Mikata

    14th International SPACC-CSJ Symposium, Nov. 2008

  • Development of Carbohydrate-Based Ligand Bearing N-(2-Pyridylmethyl)glycine Frame.

    MIKATA Yuji; Y. Noguchi; Y. Mikata

    14th International SPACC-CSJ Symposium, Nov. 2008

  • Design for Hg-selective fluorescent probes with alkanedithiol scaffold.

    MIKATA Yuji; F. Nakagaki; Y. Mikata

    14th International SPACC-CSJ Symposium, Nov. 2008

  • 高い親和性を有する蛍光性亜鉛イオンキレーターの開発

    MIKATA Yuji

    第3回バイオ関連化学合同シンポジウム, Sep. 2008

  • メトキシイソキノリン部位を有するエチレンジアミン誘導体の亜鉛イオンに対する蛍光応答

    MIKATA Yuji

    第58回錯体化学討論会, Sep. 2008

Association Memberships

  • Royal Society of Chemistry

  • 近畿化学協会

  • Society of Bioinorganic Chemistry (SBIC)

  • 錯体化学会

  • 日本化学会

  • American Chemical Society

  • 有機合成化学協会



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