Microbial Transformation of Mestranol by Cunninghamella elegans

The microbial transformation of an oral contraceptive, mestranol (1) by Cunninghamella elegans yielded two hydroxylated metabolites, 6β-hydroxymestranol (2) and 6β,12β-dihydroxymestranol (3). Metabolite 3 was found to be a new compound. These metabolites were structurally characterized on the basis of spectroscopic techniques.