Synthesis, Crystal structure, in vitro, and in silico biological studies of 2, 5-dihydroxybenzaldehyde based novel Schiff bases

Abstract The present study reports the synthesis of novel Schiff base ligands (S1-S8) derived from 2, 5-dihydroxybenzaldehyde by coupling with substituted amines. Further, the electron-donating and electron-withdrawing substituents on the amines are intended to tune the properties of the new Schiff base ligands. The chemical structures of these compounds were extensively elucidated by FT-IR, 1H-NMR, 13C-NMR, and ESI-MS. The X-ray analyses show that the compounds crystallized in a triclinic crystal system with a space group of P-1 and Z = 2 for S1. Besides, antimicrobial potency against gram-positive bacteria and gram-negative bacteria, as well as against fungi, was studied. S3 has superior inhibitory activity against all bacterial strains. The consortium of different substituent atoms on the phenyl ring and the heterocyclic ring counterpart is one of the reasons behind the recorded optimal activity. Compound S8 has potent antifungal inhibitory action against C.albicans compared to the standard antifungal, whereas Schiff base S5 also has well to moderate activity against all fungal strains. A molecular docking result indicates that these compounds could also be effective against the resistance β-ketoacyl-ACP (acyl carrier protein) synthase-I enzyme of E.coli.