(5-Oxo-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-(phenyl-hydrazono)-acetic acid ethyl ester
1,6-Dihydro-4-methoxy-6-oxo-1-phenyl-3-pyridazincarbonsaeure-methylester
3,6-bis-(1-phenylpyrazoline-5-one-3-yl)-piperazine-2,5-dione
4,6-dioxo-1-phenyl-1,4,5,6-tetrahydro-pyridazine-3-carboxylic acid