Water → 9-Dehydroandrostenedione

Beteiligte Stoffe

Reaktionsschritte

9α-Hydroxyandrostenedione (20.00 g.) is dissolved in methylene chloride (150 ml.) and cooled to -19°. Chlorosulfonic acid (10 ml.) is added while maintaining the temperature at less than or equal to -9°. After only a few minutes the reaction is shown to be nearly complete as measured by TLC. Additional chlorosulfonic acid (1 ml.) is added. Water (50 ml.) is added to the reaction mixture with the temperature rising from -18° to -1°. The phases are separated and the aqueous phase is extracted with methylene chloride (125 ml.). The organic phase is washed with aqueous sodium bicarbonate solution (10%, 50 ml.). The aqueous phases are combined and back extracted with methylene chloride. The organic phases are combined and concentrated under vacuum to approximately 80 ml. at a temperature of about 20°-23°. Heptane (100 ml.) is added and the mixture stirred for approximately 4 minute at approximately 19°. The mixture is concentrated under vacuum to approximately 100 ml. at a temperature of about 25°-30°. Heptane (50 ml.) is again added and the mixture again concentrated to approximately 100 ml. The mixture is cooled to 25° and stirred for 15 minutes, filtered, and the crystalline material washed with heptane (25 ml.) and dried under vacuum at 50° to give androsta-4,9(11)-diene-3,17-dione, 17.96 g. (89.8% weight yield, 95.3 % chemical yield); m.p. 197.5°-203.5°; [α]D +220° (chloroform); UV (methanol)λmax =240 nm (ε=16,200).

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