Brominations of Steroidal Hormone Having α, β-Unsaturated Ketone, 17-O-Acetyltestosterone, in the Presence of Silver Triflate

Abstract

Bromination of 17-O-acetyltestosterone (17β-acetoxyandrost-4-en-3-one) (1) was performed with 1, 5, and 10 eq of Br₂ in AcOH-Et₂O at room temperature. In all cases 2α, 6β- (2) and 2α, 6α-dibromo-17β-acetoxyandrost-4-en-3-one (3) were obtained, although the yields were dependent upon the conditions used. Bromination of compound 1 with 10 eq of Br₂ in the presence of silver trifluoromethanesulfonate (silver triflate, AgOTf) at room temperature for 12 h gave 2, 7α-dibromo- (4) and 2, 4, 7α-tribromo-17β-acetoxy-3-hydroxy-1-methylestra-1, 3, 5(10)-triene-6-one (5). The formations of the products were inferred on the basis of products obtained under controlled brominations of 1 in the presence of AgOTf, and of those obtained by the brominations of compounds 9-13 also in the presence of AgOTf.