2,2-Dimethyl-propionic acid (8R,9S,10R,13S,14S,17R)-17-(2-hydroxy-acetyl)-10,13-dimethyl-3-oxo-2,3,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl ester 在
lithium bromide 作用下,
以
吡啶 、
六甲基磷酰三胺 为溶剂,
反应 1.75h,
生成
21-Brom-17-trimethylacetoxy-4-pregnen-3,20-dion