Microwave-assisted CAN-catalyzed solvent-free synthesis of N-allyl quinolone-based pyrano[4,3-b]chromene and benzopyrano[3,2-c]chromene derivatives and their antimicrobial activity

Abstract

A new series of pyrano[4,3-b]chromene and benzopyrano[3,2-c]chromene derivatives have been synthesized via microwave-assisted one-pot, three-component reaction of N-allyl quinolones, cyclic β-diketones, and 4-hydroxy-6-methyl-2H-pyran-2-one/4-hydroxy coumarin in the presence of catalytic amount of ceric ammonium nitrate under solvent-free condition. The protocol offers expeditious and solvent-free synthesis with excellent yield to furnish fused chromenes for their antimicrobial activity. The chemical structures of the synthesized compounds were elucidated by 1H NMR, 13C NMR, FT-IR, elemental analysis, and mass spectral data. All the compounds were screened against a representative panel of pathogenic strains by broth micro dilution minimum inhibitory concentration method. Among these derivatives, compounds 6i, 6k, 6l, and 6m were found to have admirable activity when compared to the standard drugs.