Synthesis, Antibacterial, Antioxidant, and In Silico Evaluation of New Sulfamethoxazole-Based Schiff Base and Azo Derivatives

This research involved the preparation of a new Schiff base derivative (1) and azo derivatives (2–7) based on sulfamethoxazole through the coupling reaction of diazonium salt with various phenols. The yields were very high, ranging from 81% to 91%. The synthesis of these compounds was characterized using various techniques such as FT-IR, 1H-NMR and 13C-NMR. The antioxidant activity of these com-pounds was investigated utilizing the DPPH radical scavenging assay. The findings indicated that all compounds possessed antioxidant activity that increased proportionally with increasing concentration, particularly compounds 6 and 7, possibly due to the presence of hydroxyl groups in their structures. The biological activity of the synthesized derivatives1-7 as antibacterial agents was also investigated through in silico studies, including ADME and molecular docking, and in vitro studies, including the diffu-sion inhibition method. The ADME study indicated that several synthesized derivatives exhibited physi-cochemical and pharmacokinetic properties consistent with Lipinski's criteria. The results of molecular docking with the dihydropteroate synthase protein (DHPS) showed that these compounds are capable of binding to the protein's active site through the formation of hydrogen and hydrophobic interactions with a docking score ranging between −5.279and −3.638kcal/mol. As for the biological activity test, it was carried out using four types of Gram-negative and Gram-positive bacteria, and the results showed that the compounds have varying activity, ranging from moderate to strong or no inhibition against some bacteria, while showing broad inhibition capacity against all types of bacteria used for compound 5. The results show that the synthesized sulfamethoxazole-based compounds (1-7) are attractive can-didates for the development of novel antioxidant and antibacterial drugs.