3β-Acetoxy-17-chloro-16-formylandrosta-5,16-diene 2b (100 mg, 0.26 mmol) was added to a suspension of acetamidine hydrochloride (125 mg, 1.3 mmol) and potassium carbonate (220 mg, 1.6 mmol) in DMF (4 mL). The mixture was stirred at 80°C for 8 h until the complete conversion of the intermediates (TLC monitoring). The resulting mixture was cooled to room temperature and diluted with water (30 mL). The precipitate that formed was filtered, washed with water (5 mL), and dried. The crude product was purified by column chromatography using chloroform/MeOH, 10:1, to obtain colorless solid (45 mg, 30% yield). Rf 0.45 (petroleum ether:EtOAc, 1:2; visualized by UV light at 254 nm); m.p. 158–160°C. 1H NMR (600 MHz, DMSO-d6), δ: 0.84 (s, 3H, 18-CH3), 1.01 (s, 3H, 19-CH3), 1.02–1.11 (m, 2H, 1-CH2, 9-CH), 1.32 (dt, J = 4.2, 12.6 Hz, 1H, 12-CH2), 1.36–1.41 (m, 1H, 14-CH), 1.43–1.49 (m, 1H, 11-CH2), 1.51–1.65 (m, 4H, 2-CH2, 7-CH2, 8-CH, 11-CH2), 1.69–1.73 (m, 1H, 12-CH2), 1.76–1.84 (m, 2H, 1-CH2, 2-CH2), 1.79 (s, 3H, 4′-CH3), 1.81 (s, 3H, 6′-CH3), 1.88 (dd, J = 14.4, 15.0 Hz, 1H, 15-CH2), 1.92–1.97 (m, 1H, 7-CH2), 1.98 (s, 3H, CH3CO), 2.07 (dd, 1H, J = 6.6, 15.0 Hz, 15-CH2), 2.26–2.31 (m, 2H, 4-CH2), 4.42–4.48 (m, 1H, 3-CH), 5.32 (s, 1H, 2′-CH), 5.34–5.36 (m,1H, 6-CH), 9.40 (br.s, 1H, NH). 13C NMR (125 MHz, DMSO-d6), δ: 14.8 (18-CH3), 18.8 (19-CH3), 19.9 (11-CH2), 20.3 (4′-CH3, 6′-CH3), 20.9 (CH3COO), 27.3 (2-CH2), 29.2 (15-CH2), 29.9 (8-CH), 30.3 (7-CH2), 33.4 (12-CH2), 36.3 (1-CH2), 36.3 (10-C), 37.6 (4-CH2), 47.5 (13-C), 49.8 (9-CH), 53.6 (14-CH), 67.4 (2′-CH), 73.1 (3-CH), 121.8 (6-CH), 135.4 (17-C), 138.5 (16-C), 139.8 (5-C), 152.0 (4′-C, 6′-C), 169.7 (CO). IR (KBr), cm−1: 3183 (NH), 2945, 2857 (CH), 1735 (COO),1704, 1629 (C = C, C = N). HRMS (ESI) for C26H37ClN3O3 ([M+H]+): calcd 458.2569, found 458.2558.