作者:Ahmed H. Eimasry、Ole Gisvold
DOI:10.1002/jps.2600590403
日期:1970.4
of unnatural configuration from ergosterol has been described. This method led to the preparation of 5α,8α,9α,10α-19-norpregnan-3,20-dione which possesses unnatural configuration at positions 8 and 10. The following reaction sequence was utilized to prepare this steroid. Ergosterol was photo-oxidized to give bisergostatrienol that was pyrolyzed to yield neoergosterol whose side chain was cleaved by
已经描述了一种由麦角固醇制备具有非天然构型的19-降冰片甾体的新方法。该方法导致制备在位置8和10具有非天然构型的5α,8α,9α,10α-19-去甲泼尼松-3,20-二酮。利用以下反应序列制备该类固醇。麦角固醇被光氧化以得到比麦角固醇,其被热解以产生新麦角固醇,其新的侧链通过臭氧分解被裂解,从而产生3β-羟基-19-norpregna-5,7,9(10)-20α-醛。第一次以结晶状态获得的醛通过3β-羟基-20-吗啉代-亚甲基-19-norpregna-5,7,9(10)-三烯衍生物的臭氧分解而降解,得到3β-羟基- 19-norpregna-5,7,9(10)-triene-20-one。后者用Ru /碳还原为相应的二醇,并且其环B又用Rh /氧化铝作为催化剂在环己烷中成功氢化。用琼斯试剂将二醇氧化为二酮。尽管以前已经记录了上述某些转化,但该报告描述了大多数中间体的技术和收率上的显着改进。