To a vigorously stirred solution of (20S)-4,5-epoxy-21-hydroxy-20-methylpregnan-3-one benzoate (1.0 g, 2.22 mmole) in dimethyl sulfoxide (35 mL), heated to 60° C., there was added sodium azide (2.7 g) and the concentrated sulfuric acid (0.2 mL). The mixture was quickly brought to a temperature of 100° C. and held at that temperature for 1 hour. The cooled mixture was then poured onto cold water (250 mL). The resulting mixture was extracted with ether (300 mL) and the ether solution was washed with brine, dried over magnesium sulfate and filtrate and the filtrate was concentrated to give a yellow solid which was purified by chromatography to give (20S)-4-amino-21-hydroxy-20-methylpregna-4,6-dien-3-one benzoate (0.8 g, 80.1%) melting at 163°-167° C. with decomposition. IR 3470, 3366, 1718, 1682 (m), 1656, 1608 (m), 1586 (m), 1567 (m), 1274, 1268, 718 cm-1 ; MS (CI) 448 (100%, M+1), 326 (35%, M+1 - PhCOOH); 1H NMR (CDCl3) δ 0.82 (3H, s, C18 -Me), 1.07 (s, C19 -Me), 1.15 (d, C22 -Me), 3.71 (2H, v br, NH2)4.07 (1H, dd, 1/2 C21 -CH2), 4.35 (1H, dd, 1/2 C21 -CH2), 5.98 (1H dd), 6.30 (1H dd), 7.35 (2H, t), 7.57 (1H, t), 8.04 (2H, dd).
