Microbiological hydroxylation of steroids. Part XI. Convenient routes to 3,7-, 3,11-, 3,12-, 7,11-, 7,17-, and 11,17-dioxygenated 5α-androstanes and to 5α-androstan-11-one
Suitable, readily available 3,17-dioxygenated 5α-androstanes are hydroxylated efficiently at position 11 by Aspergillus ochraceus and at position 7 by Rhizopus nigricans. These reactions, carried out on a reasonable scale, are the basis of convenient routes to derivatives of 5α-androstane (3,7-, 3,11-, 3,12-, 7,11-, 7,17-, and 11,17-dioxygenated compounds, and 5α-androstan-11-one) which are not readily accessible by chemical means.