3811-46-9 4-Pyridinecarboxylic acid, (3-ethoxy-1-methyl-3-oxopropylidene)hydrazide Ethyl acetoacetate isonicotinoylhydrazone Isonicotinic acid, (2-carboxy-1-methylethylidene)hydrazide ethyl ester Isonicotinoyl hydrazone of ethyl acetoacetate NSC243511 T-428