作者:L. N. Atopkina、V. A. Denisenko
DOI:10.1007/s10600-020-03174-0
日期:2020.9
3α,20S-Dihydroxydammar-24-en-12-one 3-, 20-, and 3,20-di-O-β-D-glucopyranosides, close structural analogs of chikusetsusaponin-LT8 glycoside from Panax japonicus, were synthesized for the first time. Condensation of 3,20S-dihydroxydammar-24-en-12-one (1) with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (6) in the presence of Ag2O gave a mixture of the three acetylated 3-, 20-, and 3,20-di-O-β-Dglucopyranosides 7–9 with 7 dominating (34.6%). Glycosylation of 3α-acetoxy-20S-hydroxydammar-24-en-12-one by glycosyl donor 6 led to regio- and stereoselective formation of acetylated 20-O-β-Dglucopyranoside 10 (48.6%). Subsequent removal of the protecting groups by sodium methoxide gave the corresponding free 3-, 20-, and 3,20-di-O-β-D-glucopyranosides 11–13.
首次合成了 3α,20S-二羟基达玛-24-烯-12-酮 3-、20-和 3,20-二-O-β-D-吡喃葡萄糖苷,它们是三七皂苷-LT8 的近似结构类似物。在 Ag2O 存在下,3,20S-二羟基达玛-24-烯-12-酮(1)与 2,3,4,6-四-O-乙酰基-α-D-吡喃葡萄糖溴化物(6)缩合,得到了三种乙酰化的 3-、20-和 3,20- 二-O-β-吡喃葡萄糖苷 7-9 的混合物,其中以 7 为主(34.6%)。糖基供体 6 对 3α-乙酰氧基-20S-羟基达玛-24-烯-12-酮进行糖基化,可形成具有区域和立体选择性的乙酰化 20-O-β-Dglucopyranoside 10(48.6%)。随后用甲醇钠去除保护基团,得到相应的游离 3-、20- 和 3,20- 二-O-β-D-吡喃葡萄糖苷 11-13。