18.6 of copper(II) bromide and 3.6 g of lithium bromide are added to 16.5 g of 7α-(5-acetoxypentyl)-11β-fluoro-estr-4-ene-3,17-dione in 190 ml of acetonitrile at 80° C. After 15 minutes, the reaction mixture is stirred into sodium bicarbonate-containing ice water. The precipitated product is suctioned off, dissolved in ethyl acetate, washed with water, dried and concentrated by evaporation in a vacuum. After the crude product is chromatographed on silica gel with a hexane-ethyl acetate gradient, 8.5 g of 7α-(5-acetoxypentyl)-11β-fluoro-3-hydroxy-estra-1,3,5(10)-trien-17-one is obtained as foam.
