Ammonium Chloride → 3alpha-Hydroxy-16alpha-methyl-5alpha-pregnane-11,20-dione

Participants

Reaction Steps

To a stirred slurry of cuprous iodide (950 mg.) in dry ether (75 ml.) under dry nitrogen at 0° was added a solution of methyl-lithium in ether (c 1.6M; 6 ml.) until the initially formed yellow precipitate just redissolved to give a clear solution. To the stirred solution at 0° was added a solution of 3α-hydroxy-5α-pregn-16-ene-11,20-dione (600 mg.) in dry tetrahydrofuran (50 ml.). During the addition a bright yellow precipitate formed. The mixture was stirred at 0° for 30 minutes, and then poured into cold, saturated ammonium chloride solution (200 ml.). More ether (200 ml.) was added, and the organic layer was separated, washed with saturated ammonium chloride solution (200 ml.) and with water (200 ml.) dried over sodium sulphate and purified by preparative t.l.c. in ethyl acetate to give a product which was further purified by preparative t.l.c. in ethyl acetate/chloroform, 1/l to give a white solid (380 mg.) which was recrystallised from ether/petrol to give title compound (248 mg.) as colourless plates, m.p. 138°-140°, [α]D + 99°, (c 0.95).

Provenance & Evidence