The chemistry of 9 alpha-hydroxy steroids. 2. Epimerization and functionalization of 17 alpha-ethynylated 9...

Practical routes to 9 alpha-hydroxypregnenes were developed by epimerization and hydration of 17 alpha-ethynyl-9 alpha,17 beta-dihydroxyandrost-4-en-3-one. In the three different methods of epimerization which were used, the C-9 alpha hydroxy group was not susceptible to rearrangement or other side reactions. C-21 functionalized 9 alpha-hydroxypregnenes were obtained by introducing a 17 alpha-halogenated ethynyl group into 9 alpha-hydroxyandrost-4-ene-3,17-dione. Epimerization and hydration by the 17 beta-nitrooxy method produced 21-halogenated 9 alpha-hydroxypregnenes, which were further converted into 21-acetoxy-9 alpha-hydroxypregn-4-ene-3,20-dione.