Synthesis, structure analysis, biological activity and molecular docking studies of some hydrazones derived from 4-aminobenzohydrazide

Abstract

(E)-4-Amino-N′-(substituted benzylidene) benzohydrazides (1-8) were synthesized by condensing 4-aminobenzohydrazide with an appropriate aldehyde in the molar ratio of 1:1 in methanol as solvent. Single crystal X-ray diffraction has been recorded for compound 1. For all the synthesized compounds, FT-IR,1H and 13C NMR spectra have been recorded. Also antibacterial and docking studies have been done for all compounds 1-8. Since for compound1 only single crystal X-ray analysis has been carried out, its structural characterization have been done in detail, characterisation of remaining compounds 2-8 have been carried out by comparing their FT-IR, 1H and 13C NMR spectral data with that of compound 1. Single crystal X-ray analysis of 1 show that the compound exists in E-configuration about azomethine double bond. The crystal state of the compound was stabilised by the hydrogen bond present in the molecule. DFT calculations using the B3LYP/6-311++G method have been carried out for 1 to get the optimized geometry, IR and NMR frequencies, Mulliken charge distribution, molecular electrostatic potential (MEP) and energies of HOMO – LUMO. A good agreement between the DFT predicted and the experimentally measured IR and NMR spectra of 1 was found. Analysis of MEP and Mulliken atomic charges bar diagram of 1, confirms the chemical reactivity and existence of intermolecular hydrogen bonding of the molecule. The result of antibacterial and antifungal activities shows that the compounds 2, 4, 7 and 8 showed good antibacterial activity against the tested bacteria and the compounds 1, 3, 5 and 6showed good antifungal activities against all the three fungal strains. These results showed that electron donating and electron withdrawing groups play important roles in antibacterial and antifungal activities of the compounds1-8, respectively. Molecular docking studies of compounds 1-8shows that the various ligand of compounds 1-8 shows glide score values lies between -5.923 to -7.298, among these the compounds 6 and 8 showed excellent glide score values.