Methanesulfonyl chloride → (E)-5-Methysulfonylamino-1-(2-pyridyl)-2-styryl-1H-benzimidazole

Participants

Reaction Steps

To a stirred solution of (E)-5-amino-1-(2-pyridyl)-2-styryl-1H-benzimidazole (162 mg, 0.52 mmol) in dichloromethane (3 ml) and pyridine (1 ml) was added a solution of methanesulfonyl chloride (63 mg, 0.55 mmol) in dichloromethane (2 ml) dropwise. The reaction mixture was stirred for 2 h at room temperature and then partitioned between ethyl acetate (50 ml) and saturated aqueous sodium bicarbonate solution (50 ml). The organic phase was separated and the aqueous phase was extracted with ethyl acetate (50 ml). The combined extracts were washed with brine (50 ml), dried (sodium sulfate) and concentrated in vacuo to give brown oil. It was purified by column chromatography (silica gel, 20 g; n-hexane/ethyl acetate (5/1)). Recrystallization of the residue from ethyl acetate afforded 70 mg (34%) of the titled compound as off white solids. MW: 390.47; mp: 133.5-134.9° C.; 1H-NMR (CDCl3) δ: 8.79 (1H, dd, J=5.1, 1.8 Hz), 8.02 (1H, d, J=16.1 Hz), 7.99 (1H, ddd, J=7.7,7.7, 1.8 Hz), 7.67 (1H, d, J=2.2 Hz), 7.55-7.46 (4H, m), 7.43 (1H, d, J=8.8 Hz), 7.41-7.30 (3H, m), 7.23 (1H, dd, J=8.8, 2.2 Hz), 7.10 (1H, d, J=16.1 Hz), 6.86 (1H, br.s), 3.00 (3H, s).

Provenance & Evidence