1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-5-oxo-, hydrazide 2-Pyrazoline-3-carboxylic acid, 5-oxo-, hydrazide 5-Oxo-2-pyrazoline-3-carboxylic acid hydrazide 73972-70-0 NSC80276 WLN: T5NMV DHJ EVMZ