Experimental and computational insights for identification of dialkyl 5-oxo-5H-[1,3] thiazolo[3,2-a]pyrimidine-2,3-dicarboxylates

The two-component reaction of 2-thiouracil and dialkyl acetylenedicarboxylate in solvent-free conditions occurred under thermal conditions and dialkyl 5-oxo-5H-[1,3]thiazolo[3,2-a]pyrimidine-2,3-dicarboxylate derivatives produced were formed. The reaction proceeded smoothly and cleanly under mild reaction conditions. The structures of the products were confirmed by IR, 1H NMR, 13C NMR, and elemental analysis. We also used ethyl phenylacetylenecarboxylate and methyl acetylenecarboxylate in this reaction, but no reaction happened. Stability, dipole moment, and global reactivity parameters of the dimethyl 5-oxo-5H-[1,3]thiazolo[3, 2-a]pyrimidine-2,3-dicarboxylate molecule were calculated at the CAM-B3LYP/6-311G(d,p) level of theory.