3β-tetrahydropyran-2'-yloxy-24-methylcholesta-5,22,24-trienoic acid 在
N-溴代丁二酰亚胺(NBS) 作用下,
以
氯仿 为溶剂,
以20%的产率得到2-[(3S,8S,9S,10R,13R,14S,17R)-17-((2E,4Z)-(R)-5-Bromo-1,4-dimethyl-hexa-2,4-dienyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yloxy]-tetrahydro-pyran