Azilsartan Des-Ethyl Impurity

2-Hydroxy-3-[2'-(5-oxo-4,5-dihydro-[1,2,4]oxadiazol-3-yl)-biphenyl-4-yl methyl]-3H-benzoimidazole-4-carboxylic acid 5-methyl-2-oxo-{1,3}dioxol-4-ylmethyl ester.