“Novel Synthesis and Antimicrobial Properties of Pyrazolone Mannich Bases by ultrasound technique”
The present work is mainly designed to synthesize a variety of new pyrazolone derivatives from cyclization of salicylaldehyde with diethylmalonate in presence of catalytic amount of imidazole. Reaction of this ester compound with hydrazine hydrate in ethanol formed 2-oxo-2H-chromene-3- carbohydrazide. The key intermediate was prepared by cyclization of compound with ethyl acetoacetate in presence of glacial acetic acid. The condensation of pyrazolone with formaldehyde (60%) and various aromatic primary amines resulted in the formation the corresponding Mannich base derivativesThe salient features of this method include simple procedure, mild conditions, no waste produced, easy purification, moderate to good yields of products and high generality.