(25R)-3 beta,26-Dihydroxy-5 alpha-cholest-8(14)-en-15-one (1) and (25R)-3 beta,26-dihydroxy-5 alpha,14 beta-cholest-16-en-15-one (2) were synthesized from (25R)-3 beta,26-dibenzoyloxy-5 alpha,14 alpha-cholest-16-ene (4). Oxidation of 4 with CrO3-3,5-dimethylpyrazole at -20 degrees C gave (25R)-3 beta,26-dibenzoyloxy-5 alpha,14 alpha-cholest-16-en-15-one (5) along with (25R)-3 beta,26-dibenzoyloxy-5 alpha-cholest-16 alpha,17 alpha-epoxide (6). Oxidation of 5 with selenium dioxide afforded (25R)-3 beta,26-dibenzoyloxy-5 alpha-cholest-8(14),16-dien-15-one (7) and (25R)-3 beta,26-dibenzoyloxy-5 alpha,14 beta-cholest-16-en-15-one (8). Selective hydrogenation of 7 followed by hydrolysis in alcoholic potassium hydroxide yielded (25R)-3 beta,26-dihydroxy-5 alpha-cholest-8(14)-en-15-one (1). Hydrolysis of 5 and 8 in alcoholic potassium hydroxide provided (25R)-3 beta,26-dihydroxy-5 alpha,14 beta-cholest-16-en-15-one (2). (C) 1999 Elsevier Science Inc. All rights reserved.
(25R)-3β,26-二羟基-5α-胆甾-8(14)-烯-15-酮(1)和(25R)-3β,26-二羟基-5α,14β-胆甾-16-烯-15-酮(2)由(25R)-3β,26-二苯甲酰氧基-5α,14α-胆甾-16-烯(4)制得。将4与
CrO3-3,5-二甲基
吡razole在-20℃下氧化,得到(25R)-3β,26-二苯甲酰氧基-5α,14α-胆甾-16-烯-15-酮(5)和(25R)-3β,26-二苯甲酰氧基-5α-胆甾-16,17-
环氧化物(6)。将5与亚
硒酸氧化,制得(25R)-3β,26-二苯甲酰氧基-5α-胆甾-8(14),16-二烯-15-酮(7)和(25R)-3β,26-二苯甲酰氧基-5α,14β-胆甾-16-烯-15-酮(8)。对7进行选择性加氢,随后在
乙醇钾中进行
水解,得到(25R)-3β,26-二羟基-5α-胆甾-8(14)-烯-15-酮(1)。在
乙醇钾中对5和8进行
水解,得到(25R)-3β,26-二羟基-5α,14β-胆甾-16-烯-15-酮(2)。(C) 1999 Elsevier Science Inc. All rights reserved.