Design, Synthesis, And Characterization Of New Schiff Bases For 3-Amino-1,2,4-Triazole-5-Thiolate Salt, Bearing Morpholine Ring And Biological Evaluation As Antibacterial Agents

Schiff bases (T1-T10) were prepared from the reaction of various benzaldehyde derivatives with 3-amino-1,2,4-triazole-5-thiol in the presence of Morpholine, and all the prepared compounds were characterized using UV, FIR spectroscopy, in addition to GC-Mass, 1H-NMR for some combinations and measuring their melting points. The obtained results confirmed the validity of the proposed structures of the prepared compounds. The biological activity of all prepared compounds (T1-T10) was tested against four types of Gram-positive and Gram-negative bacteria. The study showed that the compound T8 inhibited Staphylococcus aureus with an IC50 of 22 µg/mL, followed by T1, T10, T2, and T3 with IC50 values of 25, 26, 33, and 33 µg/mL, respectively. In addition, T3, T10, T2, T1, and T4 had an inhibitory effect on Pseudomonas aeruginosa with IC50 values of 22, 28, 39, 44, and 50 µg/mL, respectively. T4, T2, and T5 inhibited Streptococcus mutans with IC50 values of 28, 32, and 38 µg/mL, respectively. Interestingly, T6 had the strongest inhibitory effect on Klebsiella pneumoniae with an IC50 of 15 µg/mL. The results of this study suggest that T8, T3, T4, and T6 may be potential new antibiotics for the treatment of Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans, and Klebsiella pneumoniae. However, further studies are needed to confirm these findings and to evaluate the safety and efficacy of these compounds in humans.