A microwave-catalyzed rapid, efficient and ecofriendly synthesis of substituted pyrazol-5-ones (Short communication)

A series of 1-(3,4-dihydro-3-oxo-2H-1,4-benzoxazine-2-carbonyl)-3-methyl-4-(substituted phenylhydrazono)-2-pyrazolin-5-ones have been synthesized by the reaction of 2H-3,4-dihydro-3-oxo-1,4-benzoxazine-2-carboxylic acid hydrazide with substituted acetoacetic ester derivatives using acetic acid as solvent under microwave irradiation (MWI), as well as by conventional methods. The reaction rate is enhanced tremendously and the yields are improved under MWI as compared to conventional methods.