17β-hydroxy-2α,3α-isopropylidenedioxy-B-homo-7-oxa-5α-androstan-6-one 、
dicyclohexylamine salt of N-benzyloxycarbonyl-L-leucine 在
4-二甲氨基吡啶 、 Dowex 50 (H
(1+)) 、
N,N'-二环己基碳二亚胺 作用下,
生成 2α,3α-isopropylidenedioxy-6-oxo-7-oxa-B-homo-5α-androstan-17β-ol 17-(N-benzyloxycarbonyl-L-leucinate)