2-(2,4-dichloro-phenyl)-7-methoxy-1H-benzoimidazole-4-carboxylic acid methyl ester (1.9 g, 5.47 mmol) obtained in step 2 was dissolved in 100 ml of toluene, aluminum chloride (3.61 g, 27.05 mmol) was added thereto and refluxed for 8 hours. The resulting solution was cooled to room temperature, the reaction was stopped by adding 3 N HCl thereto and stirred for 30 min. The precipitate formed was filtered, washed with benzene and dried to obtain the title compound (1.63 g, 5.03 mmol) in a yield of 92%.
