PROCESS FOR THE PREPARATION OF METHYLENE DERIVATIVES OF ANDROSTA-1,4-DIENE-3,17-DIONE

摘要

The invention relates to a new process for the preparation of known aromatase inhibitors of the following formula wherein each of R1 and R3, independently, is hydrogen or C1-C6 alkyl; R2 is hydrogen, halogen or C1-C6 alkyl and R4 is hydrogen or fluorine; the process comprising subjecting to Mannich reaction a compound of formula wherein R1,R2,R3 and R4 are as defined above, and then oxidizing the respective 6-methylene derivative thus obtained by methods known per se.