4-(3-hydroxybutoxy)-3-(phenylsulfonyl)-1,2,5-oxadiazole 2-oxide 、 4-(((3S,4aR,6aR,6bS,8aS,12aS,14aR,14bR)-8a-(ethoxycarbonyl)-4,4,6a,6b,11,11,14b-heptamethyl-1,2,3,4,4a,5,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-icosahydropicen-3-yl)oxy)-4-oxobutanoic acid 在
4-二甲氨基吡啶 、
N,N'-二环己基碳二亚胺 作用下,
以
二氯甲烷 为溶剂,
以65.3%的产率得到28-ethoxy-28-oxoolean-12-en-3-yl 1-methyl-3-{[5-oxido-4-(phenylsulfonyl)-1,2,5-oxadiazol-3-yl]oxy}propyl succinate