苷类研究ⅩⅩⅥ: 苯丙素苷Eutigoside A的合成研究

首次报道了苯丙素苷类化合物EutigosideA,即1-O-2-(4-羟基苯基)乙基]-6-O-(E)-香豆酰基-β-D-吡喃葡萄糖的全合成。从四乙酰溴代葡萄糖出发,经过成苷、脱乙酰基两步反应,制备了2-对烯丙氧基苯基-β-D-吡喃葡萄糖苷(3),采用酰氯法在低温下将对乙酰氧基肉桂酰基引入化合物3的葡萄糖6位,再经过脱烯丙基、脱乙酰基两步,便顺利地合成了天然苯丙素苷EutigosideA。以化合物3为原料,经过对葡萄糖4,6位亚苄基化、2,3位乙酰化、4,6位脱亚苄基、选择性6位乙酰化及4位引入对乙酰氧基肉桂酰基等五步反应,得到了保护的苯丙素苷(OsmanthusideA(10);但在NH~3/MeOH条件下脱乙酰基时,化合物10中的香豆酰基从葡萄糖的4位迁移至6位,最终又得到了EutigosideA。

Studies on Glycosides XXVII. Total Synthesis of the Phenylpropanoid Glycoside,Eutigoside A

Eutigoside A, 2-(4-hydroxyphenyl) ethyl-6-O-coumaroyl-β-D- glucopyranoside, was synthesized for the first time. 2-(4- Allyloxyphenyl) ethyl-4-O-(4-O-acetyl) coumaroyl-2, 3, 6-tri-O-acetyl- β-D-glucopyranoside (10) was synthesized from 2-O-(4-allyloxy- phenyl) ethyl-β-D-glucopyranoside (3) in 5 steps with the aim of the synthesis of Osmanthuside A. It was found surprisingly that the coumaroyl group migrated from the 4- to 6-position of the glucopyranoside during the deacetylation of 10 with NH~3/MeOH.