The 3a-(4-Chlorophenyl)-1-thioxo-2,3,3a,4-tetrahydroimidazo[1,5-a]quinazolin-5(1H)-one

With the aim of producing new heterocycle molecules, the previously reported 2-(aminomethyl)-2-(4-chlorophenyl)-2,3-dihydroquinazolin-4(1H)-one was converted efficiently by reacting with N,N '-dithiocarbonyldiimidazole (DTCI) to produce the substituted imidazolidine-2-thione moiety inserted in a three-fused-ring scaffold of the title compound. The molecular composition was confirmed by a high-resolution MS experiment, and its structure was elucidated by H-1, (CNMR)-C-13, and IR analyses. The thioacetamide form of the product was supported by density functional theory (DFT)-NMR analysis where C-13 chemical shifts of the thioacetamide form and of its iminothiol tautomer were calculated in chloroform at the BP86/Jgauss-TZP2 level of theory. The very strong linear correlation between C-13 chemical shifts from experimental findings and by calculation for the NHC=S form confirmed the structure.