Synthesis, Spectroscopic Characterization, and Time-Dependent DFT Calculations of 1-Methyl-5-phenyl-5-pyrido[1,2-]quinazoline-3,6-dione and Its Starting Precursor in Different Solvents.

In this study, 2-mercapto-3-phenyl-2,3-dihydro-1-quinazolin-4-one (), which exists as a thiol and thione tautomer, was treated with acetylacetone to give the target compound, namely, 1-methyl-5-phenyl-5-pyrido[1,2-]quinazoline-3,6-dione (). The spectroscopic data, including UV/Vis, IR, H NMR, C NMR, and mass data, of this compound were recorded. The molecular structures of the starting material () and the product () were optimized by using density functional theory (DFT) by employing the B3LYP exchange correlation with the 6-311G (d, p) and 6-31G++ (d, p) basis sets.