Boron tribromide → 5-chloro-2-(1-cyclohexylmethyl-5,6-difluoro-1H-benzoimidazol-2-yl)-phenol

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Reaction Steps

To a stirred solution of 2-(4-chloro-2-methoxy-phenyl)-1-cyclohexylmethyl-5,6-difluoro-1H-benzoimidazole (1.95 g, 5 mmol) in dichloromethane (40 ml) was added boron tri bromide (1M solution in dichloromethane; 21 ml, 21 mmol) at 25° C., and the resulting mixture was allowed to stir for 16 h at the same temperature. The reaction mixture was then quenched with saturated aqueous solution of sodium bicarbonate solution and further diluted with dichloromethane (30 ml). The organic layer was washed with water, and then with brine, dried over sodium sulfate, filtered, and evaporated under reduced pressure to afford the crude material. Crude product was purified by column chromatography using silica gel (5-10% ethyl acetate/n-hexane) to give the desired compound as a colorless powder (62%). MS (Turbo Spray): m/z=376.9 (M+H).

Provenance & Evidence