N-bromobutanimide → 9-Bromo-6-[1-(difluoromethoxy)-2,2,2-trifluoroethyl]-1-(2-methoxy-4,6-dimethylpyrimidin-5-yl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole

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Reaction Steps

N-Bromosuccinimide (190 mg, 1.07 mmol) was added to a stirred solution of 6-[1-(difluoromethoxy)-2,2,2-trifluoroethyl]-1-(2-methoxy-4,6-dimethylpyrimidin-5-yl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole (469 mg, 1.02 mmol) in acetonitrile (5.0 mL) at room temperature, and the mixture was stirred at room temperature for 5 hr. The mixture was diluted with saturated aqueous sodium hydrogen carbonate and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel eluting with a 70-100% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give a solid, which was recrystallized from ethyl acetate/n-hexane to give the title compound as colorless crystals (330 mg, 0.615 mmol, 60%).

Provenance & Evidence