The approaches to the synthesis of various 16α,17α-disubstituted pregna-4,9-dien-3,20-diones from the corresponding 9α-derivatives with labile epoxide, dioxolane, and oxathiolane ringsD′ have been studied. The transformation has been found to proceed efficiently when the 9α-sulfinic esters are used at the intermediate stage and then elimination of sulfinic acid by TsOH/SiO2 is carried out.
已经研究了从相应的 9α-衍
生物与不稳定的
环氧化物、二
氧戊环和氧
硫杂
环戊烷环 D' 合成各种 16α,17α-二取代的孕-4,9-二烯-3,20-二酮的方法。当在中间阶段使用 9α-亚
磺酸酯,然后通过 TsOH/SiO2 消除亚
磺酸时,已经发现转化有效地进行。