Patent ID: 7884214

Claim:
A process for the preparation of Telmisartan comprising: condensing 4-Methyl-2-n-propyl-11H-benzimidazole-6-carboxylic acid with N-Methyl-O-phenylenediamine dihydrochloride in the presence of polyphosphoric acid (PPA) yields 4-methyl-6 (1-methyl benzimidazol-2-yl)-2-n-propyl 1H-benzimidazole; treating 4-methyl-6-(1-methyl benzimidazol-2-yl)-2-n-propyl-1H-benzimidazole with 4′-(bromomethyl)-2-biphenyl-2-carboxylate in presence of a base in an organic solvent followed by treatment with mineral acid yields acid addition salt of 4′-[4-Methyl-6-(1-methyl-1H-benzimidazol-2-yl)-2-n-propyl-1H-benzimidazol-1-1-yl-methyl]biphenyl-2-carboxylate ester; treating 4′-[4-Methyl-6-(1-methyl-1H-benzimidazol-2-yl)-2-n-propyl-1H-benzimidazol-1-yl-methyl]biphenyl-2-carboxylate ester acid addition salt with aqueous hydrochloric acid yields Telmisartan dihydrochloride; and converting Telmisartan dihydrochloride to Telmisartan.