An improved synthesis of 18-norandrost-4-ene-3,17-dione

Article abstract of DOI:10.1016/0039-128X(93)90051-N

We describe the synthesis of 13β- and 13α-H-18-nor-androst-4-ene-3,17- dione (1a and 1b) from 18-hydroxyprogesterone (18 → 20) hemiketal, via the 18-acetoxy-17β-hydroxyandrost-4-en-3-one formed by a modified Baeyer- Villiger reaction. Saponification of 18-acetoxyandrost-4-ene-3,17-dione with sonication, then retroaldolization in the presence of a formaldehyde trap, methone, afforded the mixture of 1a and 1b with 80% yield in a 'one-pot' procedure and at room temperature. This yield was greatly improved, compared with the already published procedure.