Novel D-Ribofuranosyl Tetrazoles: Synthesis, Characterization, In Vitro Antimicrobial Activity, and Computational Studies

Abstract

The goal of this study was to synthesize and evaluate new antimicrobial compounds. We specifically focused on the development of 2,5-disubstituted tetrazole derivatives containing the O-methyl-2,3-O-isopropylidene-(D)-ribofuranoside groups through N-alkylation reactions. The synthesized compounds were characterized using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Their antibacterial activity was tested against Pseudomonas aeruginosa, Escherichia coli, Streptococcus fasciens, and Staphylococcus aureus. Density functional theory (DFT) was applied to examine the electronic properties, including the highest occupied molecular orbital (HOMO)–least unoccupied molecular orbital (LUMO) gap, hardness, softness, density of states (DOS), and molecular electrostatic potential. Additionally, crystal structure modeling of protein 7AZ5 was performed to study the binding affinities through hydrophobic interactions and hydrogen bonding. Molecular dynamics simulations were carried out for 100 ns and OPLS_2005 force field re performed to investigate the stability of 3c and 5c into 7AZ5 binding site. Root-mean-square deviation (RMSD), root mean square fluctuation (RMSF), and intermolecular interactions analysis showed that these two compounds may gave relative stability into the 7AZ5 binding site. Several of the N-ribofuranosyl tetrazole derivatives synthesized displayed a strong antibacterial activity. Compounds 1c and 5c were particularly effective, with a minimum inhibitory concentration (MIC) of 15.06 μM and 13.37 μM, respectively, against E. coli and S. aureus both surpassing the efficacy of chloramphenicol (19.34 μM) and ampicillin (28.62 μM). These compounds also displayed the highest binding energies in protein modeling, indicating strong interactions with the DNA polymerase sliding clamp of E. coli. Compounds 1c and 5c show promise as potent antibacterial agents with notable chemical stability and favorable binding profiles. These findings suggest that these derivatives may serve as valuable leads for the development of new antimicrobial drugs.