2-Methyl-4-oxo-N-(4-oxo-2-phenyl substituted-1,3-thiazolidin-3-yl)-3,4-dihydroquinazoline-5-carboxamides--a new range of fluorescent whiteners: synthesis and photophysical characterization.

Fluorescent quinazolinones were synthesized form ethyl 2-methyl-4-oxo-3,4-dihydroquinazoline -5-carboxylate intermediate. The photophysical properties of the compounds were evaluated in DMF solvent. The experimental absorption and emission of the compounds were compared with the vertical excitation and emission obtained Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) computation. Application of the fluorescent compounds as a fluorescent brightening agent was tested on polyester fiber. Changes in the electronic transition, energy levels, and orbital diagrams of quinazolin-4(3H)-one analogues were investigated using the DFT computations and were correlated with the experimental spectral data. The experimental absorption and emission wavelengths are in good agreement with those predicted using the DFT and TD-DFT.