Dimethylformamide → 2-(2-Formyl-3,5-dimethyl-pyrrol-4-yl)-5-benzoylbenzimidazole

Participants

Reaction Steps

Phosphoryl chloride (2.43 g) was slowly added dropwise to N,N-dimethylformamide (15.9 g) at room temperature, and stirred at room temperature for 30 minutes. To this mixture, an N,N-dimethylformamide solution of the 2-(2,4-dimethyl-pyrrol-3-yl)-5-benzoylbenzimidazole (2.5 g) obtained in Example 7 was slowly added dropwise. After stirring for 2 hours, 50 ml of a 1 N sodium hydroxide aqueous solution was added, heated to 80° C., and stirred for 2 hours. After the starting material was disappeared, reaction mixture was slowly added to water, and precipitate was collected by filtration. The solid was dried in vacuo to afford 2-(2-formyl-3,5-dimethyl-pyrrol-4-yl)-5-benzoylbenzimidazole (1.63 g, 60%) as a brown solid.

Provenance & Evidence