A Novel Facile Synthesis of Cholesta-5,7-Diene-3β,25-Diol, the Precursor of 25-Hydroxyvitamin D<sub>3</sub>
作者:Bin Sun、Can Jin、Weike Su
DOI:10.3184/174751916x14570229632198
日期:2016.4
efficient four-step procedure is described for the synthesis of cholesta-5,7-diene-3β,25-diol from 7-dehydrodesmosterol in an overall yield of 72.4%. The 3-hydroxy group of 7-dehydrodesmosterol is protected as the acetate and the 5,7-diene system as a hetero Diels–Alder adduct with 4-phenyl-1,2,4-triazoline-3,5-dione. The key step in this synthesis is a very mild method for the hydroxybromination of
描述了一种有效的四步程序,用于从 7-dehydrodesmosterol 合成 cholesta-5,7-diene-3β,25-diol,总产率为 72.4%。7-脱氢去甲甾醇的 3-羟基被保护为乙酸盐,5,7-二烯系统作为杂狄尔斯-阿尔德加合物与 4-苯基-1,2,4-三唑啉-3,5-二酮进行保护。该合成的关键步骤是在水中用 N-溴代琥珀酰亚胺对 Diels-Alder 加合物进行羟基溴化,然后用 LiAlH4 还原和脱保护的非常温和的方法。该方法以比以前报道的更高的产率得到 cholesta-5,7-diene-3β,25-diol,并且使用的试剂都相对便宜、无毒且稳定。