Synthesis, Molecular Docking, Dynamics, Quantum-Chemical Computation, and Antimicrobial Activity Studies of Some New Benzimidazole-Thiadiazole Hybrids

Abstract

In this study, some new compounds, which are 2aminothiadiazole derivatives linked by a phenyl bridge to the 2position of the benzimidazole ring, were designed and synthesized as antimicrobial agents. The structures of the compounds were elucidated by 1H and 13C NMR spectroscopy, high-resolution mass spectrometry, and elemental analysis. The antifungal activities of the synthesized compounds were tested on Candida albicans, Candida krusei, Candida glabrata, and Candida parapsilosis. Compound 5f is more active against C. albicans and C. glabrata than standard fluconazole and varicanazole. Compounds were also evaluated for their counteracting activity against Gram-positive Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, and Pseudomonas aeruginosa and Gram-negative Enterococcus faecalis, Bacillus subtilis, and Staphylococcus aureus. Compounds 5c and 5h had minimum inhibitory concentrations against E. faecalis close to that of the standard azithromycin. Molecular docking studies were performed against Candida species' 14-alpha demethylase enzyme. 5f was the most active compound against Candida species, which gave the highest docking interaction energy. The stabilities of compounds 5c and 5f with CYP51 were tested using 100 ns molecular dynamics simulations. According to the theoretical ADME calculations, the profiles of the compounds are suitable in terms of limiting rules. HOMO-LUMO analysis showed that 5h is chemically more reactive (represented with the lower Delta E = 3.432 eV) than the other molecules, which is compatible with the highest antibacterial activity result.