Investigation of the antibacterial activity of new quinazoline derivatives against methicillin and quinolone resistant Staphylococcus aureus

Abstract

A series of 1,3,4-oxadiazole-fused and piperazine-fused quinazoline derivatives is synthesized and evaluated as antibacterial agents. The synthetic protocol involves an efficient Suzuki C–C cross-coupling reaction on the quinazoline ring followed by formation of 1,3,4-oxadiazole intermediates. These are further treated with piperazine bases in the presence of formalin in methanol to furnish the final N-Mannich products. The majority of these compounds show potent antibacterial activities against several different strains of Gram-positive bacteria including multidrug-resistant clinical isolates. The cytotoxic activity assay demonstrates that the synthesized compounds do not affect cell viability on Human cervical (HeLa) cells at their minimum inhibitory concentrations. The newly synthesized compounds are characterized by infrared spectroscopy, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis.