反应详情

In accordance with Scheme III, the epoxidation of (3β,5α)cholesta-7,14-dien-3-ol benzoate (2) to (3β,5α, 15α)-14,15-epoxycholest-7-en-3-ol benzoate (3) is carried out as described in Scheme II. Also when the epoxyolefin (3) is treated with a catalytic amount of a protic acid (preferably 70% perchloric acid) in acetone at a controlled temperature of about 23°-26° C. for 3 hours, the precursor compound (3β,5α)-3-(benzoyloxy)cholest-8(14)en-15-one (6) is obtained. However, it has been discovered that when the preceding reaction is conducted at a temperature of from about 15°-22° C. for 3 hours, the novel intermediate compound (3β,5α)-3-(benzoyloxy)cholest-7-en-15-one (5) is produced Further treatment of (5) with a protic acid (preferably 70% perchloric acid) in acetone at about 23°-26° C. for 2 hours also gives the precursor compound (6) which is refluxed with potassium carbonate in a protic solvent, preferably methanol, as described hereinbefore in Scheme II to give the product (7). The alternate debenzoylation procedures described in Scheme II may also be used to give the product (7).