4-Pyridinecarboxylic acid, (1-((4-oxo-2-thioxo-5-imidazolidinyl)methyl)pentylidene)hydrazide 5-(2-Oxohexyl)-2-thiohydantoin isonicotinoylhydrazone Isonicotinic acid, (1-((4-oxo-2-thioxo-5-imidazolidinyl)methyl)pentylidene)hydrazide US5902330