Potassium Carbonate → Methyl 9-chloro-1-[6-(dimethylamino)-2-methylpyridin-3-yl]-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole-6-carboxylate

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Reaction Conditions

Reaction Steps

Methanesulfonyl chloride (0.29 mL, 3.66 mmol) was added to a stirred solution of methyl 4-chloro-2-{[6-(dimethylamino)-2-methylpyridin-3-yl]amino}-1-(3-hydroxypropyl)-1H-benzimidazole-7-carboxylate (Reference example 121, 510 mg, 1.22 mmol) and triethylamine (0.68 mL) in tetrahydrofuran (12 mL) at 0° C. The mixture was stirred at 0° C. for 90 min, and concentrated in vacuo. A mixture of the resulting mesylate, potassium carbonate (506 mg, 3.66 mmol) in N,N-dimethylformamide (12 mL) was stirred at 80° C. for 17 hr. The mixture was diluted with 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 5-40% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the title compound as a colorless solid (341 mg, 0.853 mmol, 70% in 2 steps).

Provenance & Evidence