Steroids and related products. XLI. (1) the synthesis of 11-oxa steroids. III. (2) 17-acetoxy-11-oxaprogesterone (3).

The synthesis of 17-acetoxy-11-oxaprogesterone, the 11-oxa analogue of the orally active progestational and anti-fertility agent 17-acetoxyprogesterone, is described. An intermediate in the synthesis of 11-oxaprogesterone, 11-oxa-5alpha-pregnane-3,20-dione, available from hecogenin, was used as starting material and the 17-hydroxy function was introduced by a modified Barton oxidation. The new hormone analogue shows only extremely weak progestational activity in the oral Clauberg assay.