l-Proline promoted green and regioselective synthesis of a novel pyrazole based trifluoromethylated fused thiazolopyran scaffold and its biological evaluation

Abstract

A novel approach for the synthesis of a pyrazole based trifluoromethyl substituted fused thiazolopyran scaffold has been claimed by a one-pot four-component tandem type reaction. Pyrazolyl aldehydes 4a–e, substituted carbothioamide 8a–c, α-bromoethylacetate 9 and malononitrile 10 in the presence of L-proline as the catalyst yielded the targeted products in high yields over a short reaction time. All the compounds were screened for their preliminary in vitro antimicrobial activity against a panel of pathogenic strains and in vitro antituberculosis activity against Mycobacterium tuberculosis H37Rv. All of the compounds were found to be effective against Gram positive bacteria B. subtilis and C. tetani. Some of the compounds exhibited excellent antifungal activity against C. albicans. A few of them also exhibited moderate antituberculosis activity as compared to the first line drugs.