Synthesis, Antimicrobial Activity, and Molecular Docking Studies of Aminoguanidine Derivatives Containing an Acylhydrazone Moiety

A series of aminoguanidine derivatives containing an acylhydrazone moiety was designed based on combination principles to find new antibacterial agents with wide spectra and high activities. The synthesized compounds were characterized by spectral methods and screened for their antibacterial activity. The results showed that several compounds provided great antimicrobial activities against Gram-positive bacteria (including the multidrug-resistant clinical isolates). Especially, this series of compounds presented high potency against Staphylococcus aureus, among which the derivative 3f was the most promising one with a MIC value of 4 μg/mL. Compound 3d, with a tertiary butyl group, was found to have the broad spectrum inhibitory capacity, which is effective to eight strains and showed the most potent inhibitory activity against B. subtilis CMCC 63501 with a MIC value of 4 μg/mL. What’s more, compound 3d also presented high activities against four multidrug-resistant strains, which were comparable or potent to oxacillin and penicillin. Molecular docking studies revealed that H-bond interaction with amino acid residue THR81 and alkyl hydrophobic interaction with residue ALA246 of FabH were crucial for their binding force and in-vitro antimicrobial activities.