Wang Shao-Min, Ge Wen-Zhong, Liu Hong-Min, Zou Da-Peng, Yan Xue-Bin
Department of Chemistry, Zhengzhou University, Zhengzhou 450052, PR China.
Steroids. 2004 Sep;69(10):599-604. doi: 10.1016/j.steroids.2004.03.008.
Acetylated 3beta-O-beta-glycosyl steroid derivatives were synthesized by the reaction of a new polyhydroxysteroid 3beta,5alpha,6beta-trihydroxypregn-16-en-20-one (2) with the peracetylated 1-bromo derivatives of d-glucose and d-galactose, respectively. Subsequent protection by excess acetic anhydride in pyridine selectively gave the 6beta-O-acetylated steroid glycosides. Deprotection of the acetylated steroid glycosides separately with moderate catalysis dibutyltin oxide in methanol selectively removed all acetyl groups of sugar moiety, whereas the acetyl group of the steroid part was retained. The structures of the steroid glycosides were confirmed by mass spectrometry, NMR and IR. The complete protocol was shown to be non-destructive at all stages to the sugar moieties and the steroid nucleus. These regioselective reactions open a route to the synthesis of a series of closely related isomers of 2 and other widespread polyhydroxysteroids and steroid glycosides in marine organisms and some terrestrial species.
通过新型多羟基甾体3β,5α,6β-三羟基孕-16-烯-20-酮（2）分别与全乙酰化的d-葡萄糖和d-半乳糖的1-溴衍生物反应，合成了乙酰化的3β-O-β-糖基甾体衍生物。随后在吡啶中用过量乙酸酐进行保护，选择性地得到了6β-O-乙酰化甾体糖苷。在甲醇中用适度催化量的二丁基氧化锡分别对乙酰化甾体糖苷进行脱保护，选择性地除去了糖部分的所有乙酰基，而甾体部分的乙酰基得以保留。甾体糖苷的结构通过质谱、核磁共振和红外光谱得以确证。整个实验方案在所有阶段对糖部分和甾体核均显示无破坏作用。这些区域选择性反应为合成2的一系列紧密相关的异构体以及海洋生物和一些陆地物种中的其他广泛存在的多羟基甾体和甾体糖苷开辟了一条途径。
