Triethylamine → 1-(2,4-Dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-amine

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Reaction Conditions

Reaction Steps

A mixture of 1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole-6-carboxylic acid (9.40 g, 25.9 mmol), diphenylphosphinic acid (7.85 g, 28.5 mmol) and triethylamine (4.0 mL) in t-butanol (250 mL) was stirred at 90° C. for 12 hr and concentrated in vacuo. A mixture of the residue and trifluoroacetic acid (100 mL) in dichloromethane (50 mL) was stirred at room temperature for 20 hr and concentrated in vacuo. The residue 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 10-60% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the title compound as a yellow amorphous (440 mg, 1.32 mmol, 5%).

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