(2RS)-2-(4-isobutyrylphenyl)propanoic acid ;|(2RS)-2-[4-(2-methylpropanoyl)phenyl]propanoic acid|(2RS)-2-[4-(2-Methylpropanoyl)phenyl]propanoic acid ;|2-(4-Isobutyrylphenyl)propanoic acid|2-(4-Isobutyrylphenyl)propionic Acid;|a-Methyl-4-(2-methyl-1-oxopropyl)benzeneacetic Acid;|Ibuprofen EP Impurity J|Ibuprofen Impurity J;|α-Methyl-4-(2-methyl-1-oxopropyl)benzeneacetic Acid;