反应详情

Testosterone is treated with methyl chloroformate in pyridine to give 17β-methoxycarbonyloxyandrost-4-en-3-one in 76% yield after recrystallization from methanol. A solution of the 17β-methoxycarbonyloxyandrost-4-en-3-one in toluene is pyrolyzed at 460° C., and the crude product is recrystallized from acetone at room temperature to give androsta-4,16-dien-3-one in 90% yield. The androsta-4,16-dien-3-one is reduced at −55° with lithium tris(1,2-dimethylpropyl)hydridoborate in tetrahydrofuran to give a mixture of androsta-4,16-dien-3β-ol and androsta-4,16-dien-3α-ol; and chromatography on silica gel using dichloromethane/ethyl acetate gives pure androsta-4,16-dien-3β-ol and pure androsta-4,16-dien-3α-ol, each in 48% yield. These may be recrystallized (androsta-4,16-dien-3β-ol from cyclohexane at room temperature and androsta-4,16-dien-3α-ol from petroleum ether at −30° C.).