(S)-2-Amino-5-hydroxy-4-oxopentanoic acid 26911-39-7 5-Hydroxy-4-oxo-L-norvaline Antibiotic RI-331 L-Norvaline, 5-hydroxy-4-oxo- Levulinic acid, 2-amino-5-hydroxy-, L- (8CI) RI-331 delta-Hydroxy-gamma-oxo-L-norvaline