2,2-Dimethyl-propionic acid (3S,5R,6R,8S,9S,10R,13S,14S,17S)-3-acetoxy-6-bromo-5-hydroxy-10,13-dimethyl-hexadecahydro-cyclopenta[a]phenanthren-17-yl ester                                                                                                                                                                                                                                                                                                          生成                                                 2,2-Dimethyl-propionic acid (3S,5R,6R,8S,9S,10R,13S,14S,17S)-3-acetoxy-5,6-dihydroxy-10,13-dimethyl-hexadecahydro-cyclopenta[a]phenanthren-17-yl ester