Potassium Carbonate → 6-[(Dimethylamino)methyl]-7-hydroxy-1-(2-methoxyethyl)-N,N,2-trimethyl-1H-benzimidazole-5-carboxamide

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Reaction Steps

To a stirred solution of 7-hydroxy-1-(2-methoxyethyl)-N,N,2-trimethyl-1H-benzimidazole-5-carboxamide (1.0 g, 3.6 mmol, Step 2) and potassium carbonate (748 mg, 5.4 mmol) in N,N-dimethylformamide (36 mL) at 0° C. was added N,N-dimethylmethyleneiminium iodide (867 mg, 4.7 mmol). After stirring at the same temperature for 4 hours, the reaction mixture was quenched with saturated sodium hydrogencarbonate aqueous solution and extracted with dichloromethane. The combined organic layer was washed with brine, dried over magnesium sulfate, and concentrated in vacuo. The residue was purified by column chromatography on NH-gel eluting with ethyl acetate/methanol (30:1) to afford the title compound (855 mg, 71%) as a white amorphous.

Provenance & Evidence