Niementowski reaction: microwave induced and conventional synthesis of quinazolinones and 3-methyl-1H-5-pyrazolones and their antimicrobial activity

The Niementowski reaction has been extended to synthesize 3-substituted/2,3-disubstituted-4(3H) quinazolinones instead of the 2-substituted derivatives. The methodology is environmentally benign and completely eliminates the need of solvent for the reaction. Neat reactants were cyclocondensed under microwaves to afford, in good yield, the desired product in less irradiation time as compared to the classical technique. The compared results of microwave and conventional techniques have been discussed. 3-Methyl-1H-pyrazolones were synthesized from substituted hydrazides using various solid supports under microwave irradiation (MWI). The results obtained highlight the versatility of the solid supports. All synthesized compounds were screened for their antibacterial activity against gram positive and gram negative bacteria and showed good to significant activity, as well as demonstrated significant antifungal activity against Candida albicans ATCC 10231 and C. krusei GO3.