Nobuyuki Mitsuhashi

Tokyo Institute of Technology, Edo, Tōkyō, Japan

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Publications (2)8.8 Total impact

  • Nobuyuki Mitsuhashi · Hideya Yuasa
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    ABSTRACT: Conjugates of 2,4-diamino sugars and uridine have been synthesized as galactosyltransferase inhibitors. The relationship between inhibitory activity and the chelation abilility of the hinge-like diamino sugar towards a metal ion was studied by NMR spectroscopy. One of the conjugates exhibited a moderate inhibition that ranks between those of UDP and UMP probably through the chelation of the hinge-like diamino sugar to MnII. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
    No preview · Article · Apr 2009 · European Journal of Organic Chemistry
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    ABSTRACT: Hinged di- and trisaccharides incorporating 2,4-diamino-beta-D-xylopyranoside as a hinge unit (Hin) were synthesized. Bridging of the diamino group of Hin by carbonylation or chelation to a metal ion results in a conformational change from (4)C1 to (1)C4, which in turn causes a bending of the oligosaccharides. In this study, the bending abilities of the hinged oligosaccharides were compared, in terms of the reactivities toward carbonylation and chelation. Di- or trisaccharides containing a 6-O-glycosylated mannopyranoside or galactopyranoside at their reducing ends had bending abilities similar to that of the Hin monosaccharide, probably because there were neither attractive nor repulsive interactions between the reducing and nonreducing ends. However, when Hin was attached at O2 of methyl mannopyranoside (Man alphaMe), the bending ability was dependent on the nonreducing sugar and the reaction conditions. Typically, a disaccharide--Hin beta(1,2)Man alphaMe--was difficult to bend under all the tested reaction conditions, and the bent population in the presence of Zn(II) was only 4%. On the other hand, a trisaccharide--Man alpha(1,3)Hin beta(1,2)Man alphaMe--was bent immediately after the addition of Zn(II) or Hg(II), and the bent population reached 75%, much larger than those of all the other hinged trisaccharides ever tested (<40%). This excellent bending ability suggests an attractive interaction between the reducing and nonreducing ends. The extended conformation was recovered by the addition of triethylenetetramine, a metal ion chelator. Reversible, quick, and efficient bending of the hinged trisaccharide was thus achieved.
    No preview · Article · Nov 2005 · Chemistry