Synthesis of pennogenyl saponins using three methods
作者:S. Q. Zhang、J. S. Zhang、C. Z. Wang
DOI:10.1007/s10600-007-0153-7
日期:2007.7
The synthesis of pennogenyl saponins using three important methods of glycosylation is reported in this article. Six correlative compounds (7–12) were first synthesized. As donors (1–6), glycosyl halide, trichloroimidate, and thioglycoside were chosen to study their reaction with the acceptor pennogenin. In these reactions the difference in steric hindrance between 3-OH and 17-OH of pennogenin was utilized skillfully and only the 3-hydroxyl group of pennogenin could be connected with each kind of donors selectively. There was no reaction at the 17-hydroxyl group, which had no protection. The characteristic above makes it convenient to synthesize compounds of pennogenyl saponins.
Synthesis of a group of diosgenyl saponins with combined use of glycosyl trichloroacetimidate and thioglycoside donors
作者:Hai Yu、Biao Yu、Xiangyang Wu、Yongzheng Hui、Xiuwen Han
DOI:10.1039/a909218h
日期:——
With the combined use of glycosyl trichloroacetimidates and thioglycosides, a group of natural diosgenyl saponins (1–6) are efficiently synthesized, in either a stepwise or a ‘one-pot’ manner. The trichloroacetimidate is employed as an efficient temporary hydroxy protecting group in glycosylation with the glycosyl trichloroacetimidate. The intermolecular alkylthio-group transfer is demonstrated to be a common side-reaction during glycosylation with thioglycosides.