(2Z,8S,9S,10R,13R,14S,17R)-17-[(E,2R,5S)-5-ethyl-6-methylhept-3-en-2-yl]-2-(hydroxymethylidene)-10,13-dimethyl-6,7,8,9,11,12,14,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-3-one 、
苯甲醛 在
ammonium acetate 、
silica gel 作用下,
反应 0.1h,
以80%的产率得到2'-phenyl-(24R)-24-ethyl-cholest[3,2-d]pyrimidine-4,22-diene