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

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Reaction Steps

Methanesulfonyl chloride (7.8 mL, 35.5 mmol) was added to a stirred solution of methyl 4-chloro-1-(3-hydroxypropyl)-2-[(6-methoxy-4-methylpyridin-3-yl)amino]-1H-benzimidazole-7-carboxylate (Reference example 120, 3.60 g, 8.89 mmol) and triethylamine (6.2 mL) in tetrahydrofuran (44 mL) at 0° C. The mixture was stirred at room temperature for 13 hr, and concentrated in vacuo. A mixture of the resulting mesylate and potassium carbonate (3.67 g, 26.7 mmol) in N,N-dimethylformamide (40 mL) was stirred at 80° C. for 4 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 washed with ethyl acetate/diisopropyl ether to give the title compound as a colorless powder (1.29 g, 3.33 mmol, 37% in 2 steps).

Provenance & Evidence