New spiro-heterocyclic coumarin derivatives as antibacterial agents: design, synthesis and molecular docking

Coumarin derivatives were synthesized herein from 3-acetyl coumarin and 4-(pyrimidin-2-yldiazenyl) antipyrine, leading to the azo chalcone intermediate compound. The final spiro-heterocyclic coumarins were produced through the cyclization of the azo-chalcone with thiourea, guanidine hydrochloride, benzene-1,2-diamine, 2-aminophenol, and hydroxylamine hydrochloride, respectively. The obtained target compounds were purified by column chromatography and characterized by FT-IR, 1H NMR, 13C-NMR and elemental analysis. The antibacterial activity of the synthesized compounds was evaluated in vitro against Gram-negative and Gram-positive bacteria. One of the compounds showed significant antibacterial activity. Furthermore, the docking study of this compound with DNA gyrase for E. coli and S. aureus bacterial strains was investigated, which revealed vital interactions and binding.