Methanesulfonic Acid → 9-Dehydroandrostenedione

Participants

Reaction Steps

9α-Hydroxyandrostenedione (280 mg.; 302 mg. of 92.7% purity) is added to a solution of water (3 ml.) and methanesulfonic acid (1 ml.) and stirred at 22° for 2 hours. Additional methanesulfonic acid (1 ml.) is added and stirred for 6 hours with heating to 68°. The reaction mixture is quenched by addition of water (20 ml.) and benzene (20 ml.). Work-up gives androsta-4,9(11)-diene-3,17-dione, 147 mg. (55.7% chemical yield); m.p. 186°-195°. GC (Example 1) shows an androsta-4,9(11)-diene-3,17-dione/androsta-4,8-diene-3,17-dione ratio of greater than 99 to 1.

Provenance & Evidence