A filtered aqueous solution of chromous chloride, prepared from chromium (II) chloride (26.1 g), water (121.8 ml) concentrated hydrochloric acid (52.2 ml) and zinc powder (15.7 g) according to the method of J. R. Hanson and T. D. Organ; J. Chem. Soc.(C) 1970, 1182, was added under nitrogen to a stirred solution of 21-acetoxy-3,3-ethylenedioxy-20-nitropregna-5,16-dien-9α-ol (8.70 g as a mixture of 2 diastereomers) in acetone (1.3 1). After stirring for 45 seconds the reaction mixture was poured into an aqueous sodium chloride solution. The resulting layers were separated after which the aqueous layer was washed twice with diethyl ether (400 ml). The combined organic layers were washed once with aqueous sodium chloride solution (450 ml), dried and evaporated under reduced pressure to afford the title compound.
