Toluene → 17-(1H-benzimidazol-1-yl)androsta-4,16-diene-3-one

Participants

Reaction Steps

From a mixture of compound 5 (660 mg, 1.70 mmol), 1-methyl-4-piperidone (2.5 mL), and toluene (40 mL) was distilled off ca. 10 mL. Aluminum isopropoxide (521 mg, 2.55 mmol) was then added, and the mixture was refluxed under Ar for 4 h. After cooling, the mixture was diluted with EtOAc (50 mL), washed successively with 5% aqueous NaHCO3 (x3) and brine (x2), and then dried (Na2SO4). The solvent was evaporated, and the crude product was purified by FCC [CH2Cl2/EtOH (25:1)] to give the title compound 6 (544 mg, 82%): mp 201-204° C.; IR(CHCl3) 2946, 2858, 1622, 1611, 1490, 1453, 1376, 1291, 1270, 1228, 1189, 893, 850, 837, 722, 662, 615, 568, 553, 537, 519 cm−1; 1H NMR (300 MHz, CDCl3) δ 1.04 (s, 3H 18-CH3), 1.24 (s, 3H, 19-CH3), 5.78 (s, 1H, 4-H), 5.99 (s, 1H, 16-H), 7.31 (m, 2H, aromatic-Hs), 7.48 (m, 1H, aromatic-H), 7.81 (s, 1H, aromatic-H), and 7.95 (s, 1H, 21-H). HRMS calcd 409.2250 (C26H30ON2.Na+). found 409.2250.

Provenance & Evidence