The reaction of 11-methylene-6,11-dihydrodibenzo[b,e]oxepine-2-carboxylic acid methyl ester (I) with N-methylpiperazine and paraformaldehyde by means of trifluoroacetic acid in hot tetrachloroethane gives 11-[2-(4-methylpiperazin-1-yl)ethylidene]-6,11-dihydrodibenzo[b,e]oxepine-2-carboxylic acid methyl ester (II), which by reaction with ethyl chloroformate and sodium acetate in dichloromethane yields the corresponding 2-chloroethylidene derivative (III). The condensation of (III) with 5,6-dimethyl-1H-benzimidazole (IV) in refluxing toluene affords the methyl ester (V) of the desired product, which is finally hydrolyzed with sodium methoxide in methanol.