Synthesis and antioxidant activity screening of thiazole and oxazole derivative compounds

Thiazole and oxazole are five-membered heterocyclic compounds containing sulfur/oxygen and nitrogen in positions 1 and 3. The derivatives of these two compounds are widely applied in the pharmaceutical and medical fields because they have various biological activities such as antioxidants, antibacterial, antiviral, and anti-inflammatory. In this study, the syntheses of thiazole and oxazole derivatives are carried out. Initially, thiourea and urea are reacted with ethyl 2-chloro acetoacetate to produce thiazole and oxazole derivative compounds. The reactions of these thiazole and oxazole derivatives are based on the Hantzsch condensation. The formations of thiazole and oxazole derivatives are then characterized using melting point, thin layer chromatography (TLC), FT-IR, UV-Vis, and GC-MS. Thiazole derivative compound, ethyl 2-amino-4-methyl-1,3-thiazol-5-carboxylate, was successfully synthesized with a mass of 2.978 gram and purity of 100%. Oxazole derivative compound, ethyl 2-amino-4-methyl-1,3-oxazole-5-carboxylate, was obtained with a mixed mass of 0.8351 gram and purity of 4.69%. The antioxidant activity of thiazole and oxazole derivatives was then tested using the DPPH method and their IC₅₀ values are 64.75 and 275.3 ppm, respectively.