An Efficient, Uncatalyzed, and Rapid Synthesis of Thiazoles and Aminothiazoles Under Microwave Irradiation and Investigation of Their Biological Activity

Abstract

A convenient method for the synthesis of thiazoles by treatment of α-bromoketones with thioamides (Hantzsch synthesis) in the absence of catalysts under microwave irradiation has been developed. The products were formed rapidly in excellent yields. An efficiency comparison of time, yield, and effort clearly proved the microwave technique to be superior. The structures of the newly synthesized compounds were characterized by spectroscopic data and elemental analyses. The synthesized compounds were tested for their biological activity. Depending on the substituents, some of the thiazoles exhibit very good antibacterial or antifungal activity.

Keywords:

• Aminothiazole
• biological activity
• microwave irradiation
• thiazole
• thiourea

Acknowledgments

The authors are thankful to the Associate Editor for his constructive suggestions to modify this manuscript.

Notes

^a Emrys Optimizer microwave from Biotage using Emrys process vials (5 mL), α-bromoketone (1.5 mmol), (NH₂)₂CS (1 mmol), ethanol (3 mL).

^b Reaction monitored by TLC.

^c After chromatographic purification.

^d For exact procedures see the Experimental section.

^a All products were identified by IR, ¹H NMR, ¹³C NMR, and MS data, and elemental analyses (C, H, and N).

^b Reaction monitored by TLC.

^c Isolated yields.

^a Standard for antibacterial activity: Chloramphenicol (0.001 mol/mL). Standard for antifungal activity: Fluconazole (0.001 mol/mL).

^b Control: DMF (0.01% solution in distilled water), +ve indicates growth of microbes.