Steroid dimer formation: metal reduction of methyl androst-4-ene-3,17-dion-19-oate

Two isomeric dimeric steroids, 3,3'-bis(methyl 3-hydroxyandrost-4-en-17-on- 19-oate-3-yl), with symmetrical (alpha,alpha') and unsymmetrical structures (alpha,beta'), have been obtained by reduction of methyl androst-4-ene-3,1 7-dion-19-oate with zinc in aqueous acetic acid together with the major pro ducts, the isomeric methyl 5 alpha- and 5 beta-androst-3-en-17-on-19-oates. The structures of the dimers and unsaturated products are supported by spe ctroscopic methods. The symmetrical dimer was also obtained from treatment of the 4-en-3-on-19-oate ester with lithium in ammonia. (C) 2000 Elsevier S cience Inc. All rights reserved.