Abstract

Dana M. Hussein¹, Sahar B. Al-juboory² and Ammar A. Razzak Mahmood³

DOI : http://dx.doi.org/10.13005/ojc/330224

New derivatives of  7-hydroxy-4-methylcoumarin were synthesized via oxidation of methyl group at C4 of parent coumarin nucleus using SeO₂  as an oxidizing agent. Then the condensation with different aromatic amines and amino acids under conventional method. The structures of the title Schiff bases were elucidated by spectral analysis: FT-IR,¹³CNMR, and MS.All the compounds were tested in vitro for their preliminary antibacterial activity against two Gram-positive and two Gram –negative bacteria, using serial dilution method, and determining their minimum inhibitory concentrations for the title compounds. Most of the derivatives showed moderate to high antibacterial activity.Compound 7 showed a good antibacterial activity against Gram- positive Staphylococcus aureus and Micrococcus luteus also very potent antibacterial activity against Gram-negative E.coli. Density functional theory (DFT)calculations for the synthesized coumarins were performed using a molecular structure with optimized geometry. Molecular orbital calculations supported a full description of the orbitals, including spatial characteristics, nodal patterns, and the contributions of individual atoms.Highest occupied molecular orbital-lowest unoccupied molecular orbital energies and structures are demonstrated.

Antibacterial activity; broth dilution method; density functional theory(DFT); 7-hydroxy-4-methylcoumarin; Schiff base

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