Microwave Assisted Synthesis and Computational Approach of 5-Nitrothiophene-2-carboxaldehyde Derived Schiff Bases as Antibacterial Agents

Schiff bases were synthesized by condensation of the aldehyde group of 5-nitro thiophen-2- carboxaldehyde with different fluoro substituted aromatic primary amines. All the synthesized compounds (3a-c) were characterized by various spectral techniques and the completion of reaction were confirmed by TLC. In vitro antimicrobial activity of the synthesized compounds was evaluated using minimum inhibitory concentration against Gram-positive and Gram-negative microbial strains. The results of antimicrobial study revealed that compounds 3a and 3c were active and exhibited better inhibitory activities as compared with standard drug levofloxacin. The molecular docking studies have higher binding affinity with the receptors enzymes enoyl-ACP reductase. Density functional theory (DFT) calculations at the B3LYP method and 6-31G(d,p) basis set have been carried out to investigate the equilibrium geometry of the ligands. Moreover, total energy, energy of HOMO and LUMO and MEP and other quantum parameters were also calculated. The DFT calculations suggested the lowest energy gap of the studied compounds, which were chemically reactive and may serve as potential drug candidates.