Acetic Anhydride → 3-Acetoxy-1alpha-methylandrosta-2,4-dien-17-one

Participants

Reaction Conditions

Reaction Steps

A suspension of 15.38 g of copper(I) iodide in 50 ml of dichloroethane is cooled to -30° C., combined at this temperature with 100 ml of methyllithium solution and stirred for one hour. A solution of 12.8 g of androsta-1,4-diene-3,17-dione [J. Am. Chem. Soc. 79:3920 (1957); Tetrahedron 4:201 (1958)] in 60 ml of dichloroethane is added dropwise to this mixture in such a way that the temperature does not rise beyond -10° C. After this addition is completed, the mixture is further stirred for 2 hours at 0° C. To this yellow-brownish solution, a solution of 8.62 g of acetic anhydride in 22 ml of dichloroethane is added and the mixture is stirred for one hour at room temperature. Then a solution of 8.3 g of ammonium chloride in 83 ml of water is added dropwise thereto. The organic phase is separated, the aqueous phase is extracted with methylene chloride and the combined organic phases washed with water. After drying over sodium sulfate, the mixture is concentrated under vacuum and the resultant crude product in recrystallized from hexane/acetone, thus obtaining 8.9 g of 3-acetoxy-1α-methylandrosta-2,4-dien-17-one, mp 104°-107° C.

Provenance & Evidence