Hydrochloric Acid → 21-Chloro-5alpha-pregnane-3,11,20-trione

Participants

Reaction Steps

21-Hydroxy-5α-pregnane-3,11,20-trione (3.0 g.) in anhydrous pyridine (15 ml.) was treated with toluene-4-sulphonyl chloride (3.0 g.) and the pale orange solution was stirred at room temperature for 3 hours. The cold solution was vigorously stirred during the slow addition of ice-cold water (200 ml.) and hydrochloric acid (2N;50 ml.). The yellow crystalline precipitate was filtered off, washed well with water and dried in vacuo at 60°, and the resulting crude product (2.4 g.) was recrystallized from acetone/petrol to give crude title compound (1.13 g.) as an off-white crystalline solid, m.p. 168°-172°, [α]D + 137° (c 1.13).

Provenance & Evidence