Synthesis of ten 3-(arylideneamino)-2-phenylquinazoline-4(3H)-ones is reported. All the compounds contained a common phenyl group at the 2-position, while the substituents on the arylideneamino group were varied. The compounds were investigated for their antimicrobial activity against both Gram-positive (Staphylococcus aureus 6571 and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli K12 and Shigella dysenteriae 6) using a turbidometric assay method. It was found that the incorporation of the 3-arylideneamino substituent enhanced the anti-bacterial activity of the quinazolone system. The preliminary QSAR studies were done using some computer derived property descriptors, calculated values of partition coefficients as well as usual Hammett's sigma constants and the substituent's molar refractivity.

Fourier transform (FT)-Raman and Fourier transform infrared (FT-IR) spectra of 3-{[(4-fluorophenyl)methylene]amino}-2-phenylquinazolin-4(3H)-one were recorded and analyzed. The vibrational wavenumbers of the title compound were computed using the B3LYP/6-31G * basis and compared with the experimental data. The prepared compound was identified by NMR and mass spectra. The simultaneous IR and Raman activation of the C=O stretching mode shows a charge transfer interaction through a π -conjugated path. The first hyperpolarizability and infrared intensities are reported. The assignments of the normal modes are done by potential energy distribution (PED) calculations.

No abstract

The infrared and Raman spectra of 3-{[(4-methoxyphenyl)methylene]amino}-2-phenylquinazolin-4(3H)-one have been recorded and analysed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the Hartree-Fock and DFT (B3LYP) levels of theory using the standard 6-31G* basis. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. The proposed assignments of normal modes are based on potential energy distribution (PED) analysis. Calculated infrared intensities and first hyperpolarizability are reported. The prepared compound was identified by NMR and mass spectra. The phenyl C-C stretching modes are equally active as strong bands in both IR and Raman spectra, which are responsible for hyperpolarizability enhancement leading to nonlinear optical activity. The calculated first hyperpolarizability is comparable with the reported values of similar structures and is an attractive object for further studies of non linear optics.

No abstract