Novel Bioactive 1,4-Dihydroquinazoline Derivatives from Ciprofloxacin

This study focused on the synthesis and characterization of various cyclic compounds derived from the ciprofloxacin core, employing a series of chemical reactions. Ethanol acted as both solvent and reactant, facilitating the reversible transformation into an ester, subsequently reacting with hydrazine to form hydrazides under sulfuric acid catalysis. These hydrazides further reacted with benzaldehyde replacements to form hydrazones, which then reacted with 2-aminobenzoic acid to yield quinazolins. The synthesized compounds were thoroughly characterized using spectroscopic methods, including 13C NMR, 1H NMR, and IR. The biological activity of the compounds was evaluated using the agar-well diffusion technique against Gram-positive Staphylococcus aureus and Gram-negative E. coli. The results demonstrated the efficacy of the synthesized compounds as antibacterial agents. This study fills a gap in the literature by providing a novel approach to the synthesis of biologically active compounds derived from ciprofloxacin, with implications for the development of new antimicrobial agents.