Synthesis of rhamnosylated diosgenyl glucosides as mimetics of cytostatic steroidal saponins from Ornithogalum saundersiae and Galtonia candicans
作者:Ren� Suhr、Pascal Pfefferkorn、Saskia Weingarten、Joachim Thiem
DOI:10.1039/b309066c
日期:——
The synthesis of mimetic 3 of the steroid saponins 1 and 2 was investigated. As a substitute for the complex 22-homo-23-nor-steroid moieties A and B in 1 and 2 diosgenin C was introduced. The silyl protected thioorthoester 20 was successfully employed for glucosylation. After selective 2-O-deacetylation, the glucosylated diosgenyl acceptor 23 was rhamnosylated. The 4-O-p-methoxybenzoylated donor 12 gave only minor yields. By using the tri-O-benzoyl protected donor 15 the α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→3β)-diosgenin derivative 25 was obtained.
研究了类固醇皂苷 1 和 2 的拟态 3 的合成。作为 1 和 2 中复杂的 22-高-23-去类固醇分子 A 和 B 的替代物,引入了二糖苷 C。硅烷保护的硫代正酯 20 被成功地用于葡萄糖基化。经过选择性 2-O 去乙酰化后,葡萄糖基化的二糖原基受体 23 被鼠李糖基化。4-O-对甲氧基苯甲酰基化的供体 12 只得到少量产量。通过使用三-O-苯甲酰基保护的供体 15,得到了 α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→3β)-diosgenin 衍生物 25。