Synthesis and Characterization of Novel Thiazolo[3,2-a]pyrimidine Derivatives and Evaluation of Antioxidant and Cytotoxic Activities.

A series of novel thiazolo[3,2-a]pyrimidines were synthesized and characterized by FT-IR, 1 H, 13 C-NMR and mass techniques. Their antioxidant activities were investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and the results showed that all the synthesized compounds exhibit good antioxidant activity. In addition, it was found that any substituent on the aromatic ring of the products plays an important role in their antioxidant activity. In vitro cytotoxicity of compounds 4a-4j was investigated using MTT cell viability assay. Among these compounds, 6-ethyl 2,3-dimethyl 5-(4-chlorophenyl)-7-methyl-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-2,3,6-tricarboxylate (4e) bearing a chlorine substituent displayed the highest cytotoxic effect (IC50 =6.26±0.6 μm) in comparison with doxorubicin (IC50 =0.68±0.1 μm) as a standard after 72 h. Therefore, it is assumed that these compounds could be used as effective antioxidant and cytotoxic agents.