An improved preparation of 3-α-acetoxy-11,20-diketo-(5β)-pregnane, the key intermediate in the synthesis of 11-oxygenated corticosteroids

Abstract

Although microbiological methods of introducing oxygen at C-11 of the steroid molecule are effective, it is obvious that purely synthetic way of producing cortisone and its analogs from bile acids or hecogenin have never been abandoned. Thus, we succeeded to obtain 3alpha-L-acetoxy-11,20-diketo-(5-beta)-pregnane, the key intermediate in the synthesis of 11-oxygenated corticosteroids in a very improved yield exceeding 13% calculated on starting deoxycholic acid by the following sequence of reactions.