Process for the production of 16,17-[(cyclohexylmethylene) bis(oxy)]-11,21-dihydroxy-pregna-1,4-diene-3,20-dione or its 21-isobutyrate by transketalisation

摘要

Disclosed is a process for the preparation of a compound of formula 1, in which R is hydrogen or isobutyryl, the process comprising: reacting a compound of formula 2, in which R is hydrogen or isobutyryl, R1 is alkyl, and R2 is alkyl, with cyclohexanealdehyde.