Brominations of steroidal hormone having alpha,beta-unsaturated ketone, 17-O-acetyltestosterone, in the presence of silver triflate.
Bromination of 17-O-acetyltestosterone (17beta-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 2alpha,6beta- (2) and 2alpha,6beta-dibromo-17beta-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 2,7alpha-dibromo- (4) and 2,4,7alpha-tribromo-17beta-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.
Shimizu
T
T
Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, Japan.
Tobari
A
A
Koyanagi
J
J
Kawase
M
M
Saito
S
S
D001966:Bromine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008698:Mesylates / Q000737:chemistry*; D013739:Testosterone / Q000031:analogs & derivatives* / Q000737:chemistry*
C115972:17-O-acetyltestosterone; D008698:Mesylates; D013739:Testosterone; C012077:trifluoromethanesulfonic acid; D001966:Bromine