isopropyl (R)-1-(1-phenylethyl)-1H-imidazole-5-carboxylate Benzeneacetonitrile, α-ethyl-4-nitro- Indobufen Impurity 5 2-(3-Aminophenyl)butyric acid Indobufen Impurity 3

4-Nitrophenylacetic acid Indobufen Impurity 2 Benzeneacetonitrile, α-ethyl-2-nitro- Indobufen Benzeneacetic acid, α-ethyl-3-nitro-

ethyl 2-(4-nitrophenyl)butanoate Benzeneacetic acid, 4-(1,3-dihydro-1-oxo-2H-isoindol-2-yl)-α-ethyl-, ethyl ester Indobufen Impurity A Benzeneacetonitrile, 4-amino-α-ethyl- α-(p-Aminophenyl)butyric acid

2-[4-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)phenyl]butyric acid Benzeneacetic acid, 4-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-α-ethyl-, ethyl ester Indobufen Impurity 23