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JOURNAL OF HETEROCYCLIC CHEMISTRY, vol.32, no.6, pp.1767-1773, 1995 (SCI-Expanded)
The title compounds, 1,2-dialkyl-benzimidazole-5(6)-carboxylic acids 34-45 were prepared at four steps; 1) preparation of mono amide derivatives 1-11 by the reaction of methyl 3,4-diaminobenzoate and substituted phenyl or phenoxyacetic acid chlorides; 2) preparation of the methyl benzimidazolecarboxylates 12-22, with zinc chloride and dry hydrogen chloride gas; 3) alkaline hydrolysis of the esters 23-33; and 4) substitution of the imidazole ring with benzyl or p-fluorobenzyl bromide, in alkali medium. 2-Aryl-benzimidazole-5(6)-carboxylic acids 50-53 were prepared via the oxidative condensation of 3,4-diaminobenzoic acid and aromatic aldehydes with cupric ion.