Studies on the effect of remote substituents on the DNA binding activity of novel chiral Schiff bases

Three new chiral Schiff Bases (1S,2R)-1-(((E)-2-hydroxy-4-methylbenzylidene)amino)-2,3-dihydro-1H-inden-2-ol (L-1), (1S,2R)-1-(((E)-3-bromo-5-chloro-2hydroxybenzylidene)amino)-2,3-dihydro-1H-inden-2-ol (L-2) and (1S,2R)-1-(((E)-2-hydroxy-4-methoxybenzylidene)amino)-2,3-dihydro-1H-inden-2-ol (L-3) were synthesized and characterized by H-1 NMR, FT-IR, UV-Vis and elemental analysis (CHN). The crystal structures of L-1 and L-2 were determined by using single X-ray diffraction crystallographic technique also. It has been revealed that the remote substituents not only affect the structure of the Schiff bases (L1 and L2) but also affect the biological activity. Under physiological conditions using fluorescence quenching, UV-Vis spectroscopy and, Cyclic voltammetry, the interaction of Schiff bases with calf-thymus DNA (CT-DNA) was investigated. The present study aimed to investigate the effect of a remote substituent on the structure and DNA binding activity of the hydroxyl substituted chiral Schiff bases. The order of DNA binding affinity (K-b) calculated from the absorption spectroscopy was: L-3 >L-1 >L-2. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Three new chiral Schiff Bases (L-1, L-2, and L-3) were synthesized and characterized, with their crystal structures determined for L-1 and L-2. The study revealed the impact of remote substituents on both structure and biological activity of the Schiff bases, and investigated their interaction with calf-thymus DNA using various methods. The DNA binding affinity was found to be highest for L-3 among the three Schiff Bases.