Synthesis, characterization, and antimicrobial evaluation of new Schiff bases derived from vanillic acid conjugated to heterocyclic 4H -1,2,4-triazole-3-thiol

A multistep synthesis was established for the preparation of a new vanillic acid-1, 2, 4-triazole-3-thiol conjugate (4). Finally, several aromatized aldehydes reacted with compound (4) to produce Schiff bases derivatives (5-11). The purpose of this research is to prepare new vanillic acid derivatives with 1, 2, 4-triazole-3-thiol heterocyclic ring structures and to evaluate their antimicrobial activity in a preliminary assessment. Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR) were used to verify the structures of the newly synthesized compounds. all the final synthesized compounds (5-11) were tested for antimicrobial activity. The findings of this study demonstrate the viability of synthesizing vanillic acid combined with a 1, 2, 4-triazole-3-thiol ring derivative, which then reacted with various aldehydes to yield several new Schiff bases derivatives. Finally, the presence of an electron-withdrawing group at the fourth position (p- chloro group) of the aromatic ring improves the antibacterial activity of the derivative of the vanillic acid-triazole conjugate. Compound 8 with para chloro substituted Schiff base derivative showed potent activity when compared to other final derivatives but of no activity toward K. pneumonia.