Regioselective synthesis of long-chain ethers and their sulfates derived from methyl β-d-galactopyranoside and derivatives via dibutylstannylene acetal intermediates
作者:Alan G. Gonçalves、Miguel D. Noseda、M.E.R. Duarte、T. Bruce Grindley
DOI:10.1016/j.carres.2005.07.008
日期:2005.10
amounts of the 3,6-di-O-alkyl derivative. Performing the reaction with excess alkyl halide on the bis(dibutylstannylene) acetal resulted in more of the 3,6-di-O-alkyl derivative, particularly for the shorter alkyl bromides, but this product was never predominant. Sulfation of the dibutylstannylene acetal of methyl 3-O-tetradecyl-beta-D-galactopyranoside resulted in the 6-sulfate in 96% yield.
研究了使用长链伯烷基溴化物,癸基,十二烷基和十四烷基溴化物对甲基β-d-吡喃半乳糖苷的二丁基亚锡缩醛进行烷基化的许多不同条件。通过在适度的温度(65摄氏度)下,在氟化铯存在下,在DMF中使烷基溴化物与单二丁基亚锡缩醛在较长的时间内反应,可以得到主要产物3-O-烷基醚的最佳收率。这些产物总是伴随着少量的3,6-二-O-烷基衍生物。用过量的烷基卤在双(二丁基亚锡基)乙缩醛上进行反应产生了更多的3,6-二-O-烷基衍生物,特别是对于较短的烷基溴而言,但是这种产物从来都不是主要的。