Microbial transformation of antifertility agents, norethisterone and 17α-ethynylestradiol

The microbial transformation of oral contraceptive norethisterone (1) by Cephalosporium aphidicola afforded an oxidized metabolite, 17alpha-ethynylestradiol (2), while the microbial transformation of 2 by Cunninghamella elegans yielded several metabolites, 19-nor-17alpha-pregna-1,3,5 (10)trien-20-yne-3,4,17beta-triol (3), 19-nor-17alpha-pregna-1,3,5 (10)-trien-20-yne-3,7alpha,17beta-triol (4), 19-nor-17alpha-pregna-1,3,5 (10)-trien-20-yne-3,11alpha,17beta-triol (5), 19-nor-17alpha-pregna-1,3,5 (10)-trien-20-yne-3,6beta,17beta-triol (6) and 19-nor-17alpha-pregna-1,3,5 (10)-trien-20-yne-3,17beta-diol-6beta-methoxy (7). Metabolite 7 was found to be a new compound. These metabolites were structurally characterized on the basis of spectroscopic techniques.