Steroids CCXXVIII. The synthesis of equilin

The conversion of 19-nortestosterone acetate into 19-norandrosta-4,7-diene-3,17-dione (X) is described. The latter compound is transformed directly into equilin by a microbiological dehydrogenation process with Corynebacterium simplex , thus representing the first synthesis of this important female sex hormone. Alternate attempts to synthesise equilin are discussed.