CAS: 42831-50-5 Molecular Formula: C5H4NO3 Molecular Weight (g/mol): 126.09 MDL Number: MFCD00955655 InChI Key: VQBXUKGMJCPBMF-UHFFFAOYSA-M Synonym: 5-methylisoxazole-4-carboxylic acid,5-methyl-4-isoxazolecarboxylic acid,unii-bl2q213q2m,4-isoxazolecarboxylic acid, 5-methyl,5-methylisoxazole-4-carboxylicacid,leflunomide impurity d ep,pubchem8652,leflunomide impurity d,acmc-209jr8,ksc235o3b PubChem CID: 1425240 SMILES: CC1=C(C=NO1)C([O-])=O