反应详情

At -78°, 80 ml. of hydrogen fluoride is combined with 32 ml. of dimethylformamide, 22 g. of 17β-acetoxy-4,9(11)-androstadien-3-one, and 16 g. of N-bromosuccinimide. The mixture is allowed to stand for 1.5 hours at -30° and then introduced into a mixture of ice/water and a 25% ammonia solution. The precipitate is filtered off, dissolved in a mixture of ethyl acetate and methylene chloride, washed with water, and dried over sodium sulfate. After chromatography with acetone/hexane, 9.1 g of 17β-acetoxy-9-bromo-11β-fluoro-4-androsten-3-one is obtained; m.p. 172°-174° UV: ε239 = 16,300 (methanol).

1. customAt -78°
2. filtrationThe precipitate is filtered off
3. dissolutiondissolved in a mixture of ethyl acetate and methylene chloride
4. washwashed with water
5. dry with materialdried over sodium sulfate