Synthesis and characterization of (E)-N-carbamimidoyl -4 and (E)-4- benzenesulfonamides; biological study, DFT, molecular docking, and ADMET predictions

Imidazole-based sulphonamide Schiff bases

Abstract

Sulphonamide Schiff bases (L₁ and L₂) containing imidazole nuclei have been synthesized and evaluated for their antimicrobial and antioxidant activity. Sulfaguanidine and sulfamerazine were condensed with 4-methyl-5-imidazolecarboxalehyde to obtain ligands L₁ and L_2, respectively. The compounds were characterized by FT-IR, ¹H NMR, ¹³C NMR, UV-Vis, CHNS, and MALDI-TOF mass spectral data. The antimicrobial activity of the sulphonamide-derived Schiff bases was conducted using agar well diffusion against S. aureus, B. substilis, E. Coli, Salmonella spp., and Candida spp. Similarly, the free radicals scavenging activity of the compounds has been evaluated at 20 – 100 μg/mL using DPPH (1,1’-diphenyl-2-picryl-hydrazil), nitric oxide, and hydrogen peroxide antioxidant assays. Both compounds exhibited moderate activity against Salmonella spp. However, L₁ exhibited higher radical scavenging ability than L₂ against NO free radicals at low to high concentrations with IC₅₀ values of 84.50 and 101.59 μg/mL for L₁ and L_2, respectively. Ligand L₂ was, however, more active than L₁ against H₂O₂ free radicals at low concentrations (20 – 60 μg/mL). The optimized geometries of the compounds were docked at the active sites of cytochrome oxidase, myeloperoxidase, NADPH oxidase, xanthine oxidase, dihydropteroate synthase (DHPS), and dihydrofolate reductase (DHFR) proteins.