4-Methoxybenzenesulfonamide → 1-(2-Chlorobenzyl)-6-(4-methoxybenzenesulfonylcarbamoyl)-2-methylbenzimidazole

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Reaction Steps

N,N'-carbodiimidazole (0.431 g) was added at a time to a solution of 0.400 g of 6-carboxy-1-(2-chlorobenzyl)-2-methylbenzimidazole in 15 ml of N,N-dimethylformamide, and the mixture was stirred at room temperature for 1 hour. Subsequently, a solution of 0.498 g of 4-methoxybenzenesulfonamide and 0.405 g of diazabicycloundecene in 5 ml of N,N-dimethylformamide was added thereto, and the mixed solution was stirred at 100° C. for 67 hours. The reaction solution was cooled, and the solvent was distilled off under reduced pressure. Water and chloroform were added to the residue, and 10% hydrochloric acid was added thereto while being cooled until the aqueous layer was acidified. The resulting mixture was extracted twice with chloroform. The organic layer was washed with a saturated aqueous solution of sodium hydrogencarbonate, and the solvent was distilled off under reduced pressure. The residue was purified through silica-gel column chromatography (eluent: a mixture of chloroform and methanol at a ratio of 100:2 to 100:10). The resulting product was concentrated, and was crystallized from a mixed solution of ethyl acetate and diethyl ether. The crystals were separated through filtration, and were dried to give 0.450 g of 1-(2-chlorobenzyl)-6-(4-methoxybenzenesulfonylcarbamoyl)-2-methylbenzimidazole (217).

Provenance & Evidence