Phosphoric Acid → 9-Dehydroandrostenedione

Participants

Reaction Steps

9α-Hydroxyandrostenedione (280 mg.; 302 mg. of 92.7% purity) is added to phosphoric acid (85%, 5 ml.) and stirred at 35°-48° for 7.5 hours. Water (10 ml.) is then added, the mixture stirred and filtered. The solids are air-dried at 25° for 10 hours to give androsta-4,9(11)-diene-3,17-dione, 254 mg. (90.7% weight yield, 96.2% chemical yield); m.p. 197°-201°. GC (Example 1) shows an androsta-4,9(11)-diene-3,17-dione/androsta-4,8-diene-3,17-dione ratio greater than 99 to 1.

Provenance & Evidence