Abstract
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•Three series of nano-sized formazan analogues were synthesized and fully characterized by spectroscopic tools.•The antibacterial and antifungal activities were evaluated by agar diffusion technique.•Potant antifungal activities were observed for four derivatives on the pathogenic fungal strains.•Molecular modeling study revealed that the active antimicrobial derivatives could bind properly to C. albicans leucyl-tRNA synthetase editing domain.•Docking simulation for COVID-19 3CL protease showed superior fitting into the active site with binding scores from −5.6064 to −8.0555 Kcal/mol.
Three series of nanosized-formazan analogues were synthesized from the reaction of dithiazone with various types of α-haloketones (ester and acetyl substituted hydrazonoyl chlorides and phenacyl bromides) in sodium ethoxide solution. The structure and the crystal size of the new synthesized derivatives were assured based on the spectral analyses, XRD and SEM data. The antibacterial and antifungal activities were evaluated by agar diffusion technique. The results showed mild to moderate antibacterial activities and moderate to potent antifungal activities. Significant antifungal activities were observed for four derivatives 3a, 3d, 5a and 5g on the pathogenic fungal strains; Aspergillus flavus and Candida albicans with inhibition zone ranging from 16 to 20 mm. Molecular docking simulations of the synthesized compounds into leucyl-tRNA synthetase editing domain of Candida albicans suggested that most formazan analogues can fit deeply forming stable complexes in the active site. Furthermore, we utilized the docking approach to examine the potential of these compounds to inhibit SARS-CoV-2 3CLpro. The results were very promising verifying these formazan analogues as a hopeful antiviral agents.