Process for the preparation of Telmisartan

摘要

The present invention encompasses a method for the preparation of Telmisartan comprises, through Telmisartan dihydrochloride comprises i) Condensing 4-Methyl-2-n-propyl-1H-benzimidazole-6-carboxylic acid with N-Methyl-O-phenylenediamine dihydrochloride to yields 4-methyl-6 (1-methyl benzimidazol-2-yl)-2-n-propyl 1H-benzimidazole ii) Treating 4-methyl-6-(1-methylbenzimidazol-2-yl)-2-n-propyl-1H-benzimidazole with 4′-(bromomethyl)-2-biphenyl-2-carboxylate in presence of a base in an organic solvent and isolating the ester as acid addition salt iii) Converting ester acid addition salt to Telmisartan dihydrochloride and iv) Converting Telmisartan dihydrochloride to Telmisartan.