英文别名4-(4-Oxobutyl)benzoic Acid Methyl Ester; 4-(4-CARBOMETHOXYPHENYL)BUTANAL; Benzoic acid, 4-(4-oxobutyl)-, methyl ester; Pemetrexed Impurity 41; Pemetrexed Related Impurity 5; Pemetrexed Impurity 52; methyl p-(4-oxobutyl)benzoate; 4-(4'-Carbomethoxyphenyl)butyraldehyde; 4-p-carbomethoxyphenylbutyraldehyde; Pemetrexed Impurity 10 
