(4R,4aR,4bR,6aR,7R,8R,10aR,10bR,12aR)-hexadecahydro-8-{2-{[(4-methoxyphenyl)methyl]amino}-1,1-dimethyl-2-oxoethyl}-3,3,7,10a,10b-pentamethyl-13-oxo-1H-4,12a-(epoxymethano)chrysene-7-acetic acid 在
草酰氯 作用下,
以
四氢呋喃 为溶剂,
以74%的产率得到(1S,3aR,5aR,5bR,7aR,11R,11aR,11bR,13aS,13bR)-octadecahydro-1'-[(4-methoxyphenyl)methyl]-3,3,5a,5b,10,10,13b-heptamethylspiro[11,7a-(epoxymethano)-7aH-cyclopenta[a]chrysene-1(2H),3'-pyrrolidine]-2,2',4',5',15-pentone