6-hydroxy-2-phenyl-2-hydropyridazin-3-one, 1-phenyl-1,2-dihydropyridazine-3,6-dione, 2-phenyl-1,2-dihydro-3,6-pyridazinedione, 6-Hydroxy-2-phenyl-3(2H)-pyridazinone, 6-hydroxy-2-phenylpyridazin-3(2H)-one, 3-HYDROXY-1-PHENYL-6-PYRIDAZONE, N-Phenyl-maleinsaeure-hydrazid, 2-Phenyl-3.6-dioxo-1.2.3.6-tetrahydro-pyridazin, 1-Phenyl-1,2-dihydro-pyridazin-3,6-dion