Dihydropyrazoles containing morpholine: design, synthesis and bioassay testing as potent antimicrobial agents

A series of dihydropyrazole derivatives containing morpholine was designed and synthesized as antimicrobial agents. All of the synthesized compounds were characterized by super(1)H-NMR and MS. Afterwards they were evaluated for in vitro antibacterial activity against four bacteria strains. Along with S. aureus TyrRS inhibition and cytotoxicity examination, some compounds proved to be of low toxicity and potent, especially against Gram-positive bacteria strains. Compound 4s exhibited the potential to be new a antibacterial drug with strong broad-spectrum antimicrobial activity and enzyme inhibitory activity. Docking simulation was performed to position compound 4s into the S. aureus TyrRS structure active site to investigate the probable binding mode. A 3D-QSAR model was also established to explain how structural alterations affect the activity and guide further study.