New syntheses of d-tagatose and of 1,5-anhydro-d-tagatose from d-galactose derivatives
作者:Pier Luigi Barili、Giancarlo Berti、Giorgio Catelani、Felicia D'Andrea、Lucia Miarelli
DOI:10.1016/0008-6215(95)00125-d
日期:1995.9
3,4-O-Isopropylidene-D-lyxo-hexopyranosid-2-ulose derivatives, obtained by oxidation of 3,4,6-protected D-galactopyranosides, can be alkylated in their anionic 2,6-pyranose forms to produce bis-glycosides containing the 2,5-dioxabicyclo[2.2.2]octane ring system. The 1-benzyl-2-methyl bis-glycoside 4b, when subjected to catalytic hydrogenolysis, produces the methyl D-lyxo-hexopyranos-2-uloside 10, existing
通过3,4,6-保护的D-吡喃半乳糖苷的氧化反应制得的3,4-O-异亚丙基-D-lyxo-己吡喃糖苷-2-ulose衍生物可以阴离子2,6-吡喃糖形式烷基化生成双-含2,5-二氧杂双环[2.2.2]辛烷环系统的糖苷。1-苄基-2-甲基双糖苷4b在进行催化氢解后,生成甲基D-lyxo-己吡喃并-2-uloside 10,以1:5-吡喃糖异构体9:8的混合物形式存在。计算并提供了NMR证据,以支持主要端基异构体具有α构型的假设。用NaBH4还原9/10可得到甲基3,4-O-异亚丙基-β-D-塔格吡喃糖苷,可以水解为D-塔格糖。还介绍了从1,5-脱水D-半乳糖醇开始的1,5-脱水D-塔格糖的简单合成。