In 10 ml of dimethylformamide is dissolved 0.5 g of 16β-ethyl-17β-glycoloyloxy-4-estren-3-one, and 0.2 g of glutaric anhydride and then 0.3 ml of triethylamine are added to the above solution. The mixture is allowed to stand at room temperature (15°-25° C.) for 3 hours and poured into 20 ml of 10% aqueous sulfuric acid, followed by extraction with 100 ml of ethyl acetate. 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 is subjected to column chromatography, elution being carried out with 200 ml of ethyl acetate. The eluate is evaporated under reduced pressure to remove the solvent, giving a colorless oil, which is allowed to stand to give 0.37 g of the above-identified compound as a solid.
