3-oxobutanoic acid acetoacetic acid 161879-89-6 541-50-4 LMFA01060003 acetylacetic acid Butanoic acid, 3-oxo- 3-KETOBUTYRATE 3-oxobutanate 3-oxobutyric acid acetoacetate beta-ketobutyric acid diacetic acid oxobutyrate acetonecarboxylic acid C00164 LIN 3-OXO-BUTYRIC ACID CHEBI:15344 T0515-8577 AAE 3-oxo-butanoic acid