Process for the preparation of 17{62 -hydroxy-20-alkoxypregnane-21-oic acid derivatives

摘要

A process for the preparation of 17 beta -hydroxy-20-alkoxypregnane-21-oic acid derivatives of the formula <IMAGE> WHEREIN R1 is methyl or ethyl; R2 is hydrogen or methyl, either being in the alpha -or beta -position; R3 is lower alkyl of 1-4 carbon atoms; R4 is alkyl of 1-8 carbon atoms or benzyl; and St is the residue of a steroid ABC ring system; COMPRISES REACTING (A) A 17-OXO COMPOUND OF THE FORMULA <IMAGE> WHEREIN R1 and R2 are as defined above and St* is said steroid ABC ring system residue, St, in a form which is chemically compatible with said reaction; WITH (B) AN ENOLATE ION OF AN ALKOXYACETIC ACID ALKYL ESTER OF THE FORMULA <IMAGE> wherein R3 and R4 are as defined above.