Water → 6-(1-Azido-2,2,2-trifluoroethyl)-9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole

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Reaction Conditions

Reaction Steps

To a solution of 1-[9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]-2,2,2-trifluoroethanol (200 mg, 0.44 mmol) in tetrahydrofuran (4.0 mL) were added thionyl chloride (0.065 mL, 0.891 mmol) and 1 drop of N,N-dimethylformamide at room temperature. After stirring at room temperature for 2 hr, aqueous sodium hydrogen carbonate was added to the reaction mixture at room temperature, and the mixture was extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo to give 1-[9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]-2,2,2-trifluoroethanol (200 mg, 0.43 mmol, 93%) as pale yellow solid. A mixture of 1-[9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]-2,2,2-trifluoroethanol (68.6 mg, 0.146 mmol) and sodium azide (19 mg, 0.292 mmol) in dimethylsulfoxide (5.0 mL) was stirred at 110° C. for 20 hr. Water was added to the reaction mixture at room temperature and the mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel eluting with a 10-50% ethyl acetate/n-hexane gradient mixture to give the title compound (68.2 mg, 0.143 mmol, 98%) as a white solid.

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