EFFECT OF SOLVENT ON THE PRODUCT FORMATION IN THE REACTION OF HYDRAZINES WITH BETA-AROYL-ALPHA-{[}4(1,3-DISUBSTITUTED-2-PYRAZOLIN-5-ONE)] PROPIONIC ACIDS

The reaction of beta-aroyl-alpha-{[}4(1,3-disubstituted-2-pyrazolin-5-one)] propionic acids 1 with hydrazines in acetic acid afforded the unexpected 6-aryl-pyridazin-3-ones-3 instead of the expected 4-pyrazolinonyl pyridazinones through the fission of the 1,3-disubstituted-2-pyrazolin-5-one. A probable mechanism has been proposed. Reactions of 6-aryl-pyridazin-3-ones with dimethylsulfate, diethylsulfate, ethyl bromoacetate, phosphorus oxychloride and phosphorus pentasulfide have also been described.