Synthesis, characterization, antibacterial and antifungal activities, and molecular docking studies of two new Schiff bases derived from 2,4-diaminotoluene.

Abstract

The two symmetric Schiff bases, 3,3'-((1E,1'E)-((4-methyl-1,3-phenylene)bis(azanylylidene)) bis(ethan-1-ylidene))bis(2-hydroxy-6-methyl-4H-pyran-4-one) (DL) and (N1E,N3E)-4-methyl-N1,N3-bis(pyridin-3-ylmethylene)benzene-1,3-diamine (PL), were synthesized and characterized using UV-Vis, FT-IR,  1H NMR, 13C NMR and LC-MS techniques. The infrared and UV-Vis spectral modelling using DFT for DL and PL showed good agreement between theory and experiment. The results of the antibacterial activity tests indicate that PL was more active against all bacterial strains than DL, which exhibited moderate antibacterial activity. Moreover, both compounds DL and PL exhibited significant antifungal potency against Botrytis species. Additionally, in silico ADME-T studies suggest that these compounds may have favourable oral bioavailability and pharmacokinetic properties. In addition, molecular docking studies were conducted to evaluate how these compounds interact with the active-site residues of TEM-1 β-lactamase, an enzyme responsible for the hydrolysis of β-lactam antibiotics. The docking results suggest that the synthesized DL and PL Schiff bases may serve as preliminary scaffolds for the development of new antimicrobial agents.