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首页> 外文期刊>Bulletin of the Chemical Society of Japan >6-Nitro-2-benzothiazolyI alpha-Glucoside and alpha-Mannoside in beta-Selective Glycosylations
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6-Nitro-2-benzothiazolyI alpha-Glucoside and alpha-Mannoside in beta-Selective Glycosylations

机译：6-硝基-2-苯并噻唑鎓α-葡糖苷和α-甘糖苷，在β-选择性糖基质中

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摘要

Highly beta-selective glucosylations of glycosyl acceptors having a primary hydroxy group with a 6-nitro-2-benzothia-zolyl alpha-glucoside donor 3alpha proceeded smoothly in the presence of a catalytic amount of trifluoromethanesulfonic acid (TfOH) in CH_2C1_2 at -78 deg C to afford the corresponding glycosides in high yields.With the use of 3alpha,beta-saccharides could be obtained more dominantly than other alpha-glucosyl donors such as thioform- and trichloroacet-imidates or fluoride in the glucosylation under the same conditions.Similarly,highly beta-selective mannosylations of glycosyl acceptors with a 6-nitro-2-benzothiazolyl alpha-mannoside donor 18alpha were carried out smoothly in the presence of a catalytic amount of tet-rakis(pentafluorophenyl)boric acid H[B(C6Fs)4] to afford the corresponding disaccharides in good to high yields; 18alpha apparently behaved as a potent donor here for the construction of beta-mannoside linkage.Interestingly,in situ anomerization from 18beta to 18 alpha was observed when beta-mannosyl donor 18beta was treated with a catalytic amount of H[B(C_6F_5)_4] in CH_2C1_2.
机译：具有初级羟基的糖基受体的高度β-选择性葡糖基，其具有6硝基-2-苯并吡酰基α-葡糖苷供体3Alpha在-78°CH_2C1_2的催化量的三氟甲磺酸（TFOH）存在下平滑地进行C以高产率提供相应的糖苷。在使用3Alpha的情况下，可以比其他α-葡萄糖基供体（如硫氰酸酯 - 酰亚胺酸盐或葡萄糖苷酰亚胺酸盐或氟化物在相同条件下）更大的优异β-糖苷。它们，在催化量的TET-RAK（五氟苯基）硼酸H [B（C6FS）4]存在下，在催化量的催化量的情况下平滑地进行糖基受体的高度β-甘油酯供体18Alpha的糖基受体的甘露糖基。提供相应的二糖，良好的高产率; 18Alpha显然表现为这里的有效捐赠者，用于构建β-甘露透华键的构建。当用催化量的H [B（C_6F_5）_4]处理β-甘露糖基供体18Beta时，观察到18beta至18α的原位异常。在ch_2c1_2中。

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    Takashi Hashihayata; Hiroki Mandai; Teruaki Mukaiyama;

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    Center for Basie Research The Kitasato Institute (TCI) 6-15-5 Toshima Kita-ku Tokyo I 14-0003;

    Center for Basie Research The Kitasato Institute (TCI) 6-15-5 Toshima Kita-ku Tokyo I 14-0003;

    Center for Basie Research The Kitasato Institute (TCI) 6-15-5 Toshima Kita-ku Tokyo I 14-0003;

    The Kitasato Institute for Life Sciences Kitasato University 5-9-1 Shirokane Minato-ku Tokyo 108-8641;

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  • 正文语种 eng
  • 中图分类 化学;
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