Synthesis and biological evaluation of some new coumarinyl thiazolopyrimidinones

Abstract

Two new series of coumarin linked, linear and angularly fused thiazolo-[3,2-a]-pyrimidinones have been synthesized from 3-bromoacetyl coumarins by azole and azine approaches. Regioisomeric 5H and 7H thiazolo-[3,2-a]-pyrimidinones have been clearly distinguished by their IR and UV fluorescence spectral data. All the compounds have been characterized by analytical and spectroscopic methods. Rate and yield enhancements have been achieved using microwave irradiation. The results of in vivo diuretic activity indicate that substituents on coumarin do not enhance the activity. In vitro antimicrobial activities have shown that the compounds are specifically active against Gram-positive but are inactive against Gram-negative bacterial strains. Moderate fungal activity was observed against Candida albicans and Penicillium chrysogenum and all the compounds were found to be inactive against Aspergillus niger.

Keywords:

• 3-bromoacetyl coumarins
• 4-(3’-coumarinyl)-2-amino thiazole
• 2-mercapto uracil
• antimicrobial activity
• diuretic activity

Acknowledgements

The authors are thankful to the University Scientific Instrumentation Centre (USIC), Karnatak University Dharwad, India, for spectral and analytical data. N.B. Yaragatti is grateful to the University Grants Commission, New Delhi, for the financial assistance in the form of a Research Fellowship in Science for Meritorious Students.