Methyl Ethyl Ketone → 1-(2,4-Dichlorophenyl)-N-(1-methylpropyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-amine

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Reaction Steps

Sodium triacetoxyborohydride (171 mg, 0.807 mmol) was added to a stirred solution of 1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-amine (183 mg, 0.549 mmol) and butan-2-one (1.0 mL) in methanol (1.0 mL) at 0° C., and the mixture was stirred at room temperature for 8 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 5-50% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the solid, which was recrystallized from ethyl acetate/n-hexane to give the title compound as a colorless crystal (86.4 mg, 0.222 mmol, 40%).

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