4-Methylen-2-oxetanon Phenylhydrazin Anilin Ethyl-3-acetoxy-2-butenoat 3,3'-Dimethyl-1,1'-diphenyl-4,4'-bi-5-pyrazolon Benzoldiazoniumchlorid 5-Oxo-1-phenyl-2-pyrazolin-3-carbonsure 1,2-Dihydro-5-methyl-2-phenyl-3H-pyrazol-3-on