| abstract |
The present invention relates to an improved process for the preparation of azilsartan or its esters or salts thereof. Specifically, the invention provides a method for the preparation of highly pure methyl 1-[[2′-(4,5-dihydro-5-oxo-4H-1,2,4-oxa-diazol-3-yl)biphenyl-4-yl]methyl]-2-ethoxy-1H-benzimidazole-7-carboxylate an intermediate compound of formula (4) for azilsartan medoxomil with reduced content of desethyl impurity. The invention also involves the use of highly pure methyl 1-[[2′-(4,5-dihydro-5-oxo-4H-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]-2-ethoxy-1H-benzimidazole-7-carboxylate in the preparation of azilsartan or its esters or salts thereof, preferably medoxomil with reduced content of desethyl impurity. |