p-Toluenesulfonic acid → 5-Bromo-1-methyl-2-phenyl-1H-benzo[d]imidazole

Participants

Reaction Steps

Suspending 7.8 g (26 mmol) of 4′-bromo-N-methyl-2′-amino-benzanilide obtained in the above step (3) into 50 milliliter of xylene, and adding 1.5 g (7.7 mmol) of p-toluenesulfonic acid 1 hydrate, the resultant solution was refluxed with heating for 7 hours. After completing the reaction, the resultant solution was filtered. Dissolving the resultant solids into methylene chloride, the resultant solution was washed with 10% K2CO3 aqueous solution and with a saturated solution of sodium chloride, and then, after drying with the use of magnesium sulfate, the solvent was removed by distillation. Washing the filtrate with 10% K2CO3 aqueous solution and with saturated solution of sodium chloride, and then, after drying with the use of magnesium sulfate, the solvent was removed by distillation. Combining the above two kinds of residues after removing by distillation, the resultant product was refined with silicagel column chromatography, 6.50 g of 5-bromo-1-methyl-2-phenyl-1H-benzimidazole was obtained as white solids (yield: 89%).

Provenance & Evidence