1.4 g. of 6α-fluoro-11β-hydroxy-3,20-dioxo-16α-methyl-1,4-pregnadien-21-al is dissolved in 14 ml. of dimethylformamide and combined with 5 ml. of 2-fluoroethanol, 1.4 ml. of concentrated acetic acid, 2.8 g. of active manganese (IV) oxide, and 225 mg. of potassium cyanide. The reaction mixture is agitated for 10 minutes at room temperature and then filtered off from the manganese (IV) oxide. The filtrate is poured into water and extracted with dichloromethane. The organic phase is washed with water, dried with sodium sulfate, and concentrated under vacuum. The residue is chromatographed on silica gel. With 31-33% acetone-hexane, after recrystallization from acetone/hexane, 630 mg. of the 2-fluoroethyl ester of 6α-fluoro-11β-hydroxy-3,20-dioxo-16α-methyl-1,4-pregnadien-21-oic acid is obtained; m.p. 188.0° C. [α]D25 = +141° (chloroform). UV: ε242 = 16,900 (methanol)
