In 15 ml of dichloromethane are dissolved 0.75 g of 16β-ethyl-17β-hydroxy-4-estren-3-one and 0.5 ml of trimethylamine, and 0.5 ml of 2-(n-hexanoyloxy)propionyl chloride is added to the solution. The mixture is refluxed for 2 hours. After cooling, the reaction mixture is poured into a mixture of 100 ml of ethyl acetate and 30 ml of saturated aqueous sodium hydrogen carbonate solution. The organic layer is separated, washed with water and saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is then distilled off under reduced pressure and the residue dissolved in a small amount of diisopropyl ether. The solution is subjected to silica gel column chromatography. After serial passage of diisopropyl ether-n-hexane mixtures (2:8, 100 ml and 1:6, 300 ml), elution is carried out with 500 ml of a 1:1 mixture of the same solvents. The eluate is evaporated under reduced pressure to remove the solvent, giving 0.48 g of the above-identified compound as a light-yellow viscous oil.
