Click chemistry approach for bis-chromenyl triazole hybrids and their antitubercular activity

1,4-Disubstituted bis-chromenyl triazole hybrids 5a-m have been synthesized in a three-step reaction sequence from 4-(bromomethyl)-2H-chromen-2-ones 3a-m. The intermediate azides 4a-m underwent a regioselective 1,3-dipolar cycloaddition with a 2H-chromen-2-one linked acetylenic dipolarophile in the presence of Cu (II)/ascorbate/water/n-butanol reaction medium. Three compounds 5h-j exhibited 6.25 μg/mL MIC against M. tuberculosis. Among the compounds screened for antifungal activity, lowest MIC of 6.25 μg/mL was observed for 5c against A. niger that also exhibited DNA cleavage observed by agarose gel electrophoresis. All the compounds were moderately active against both Gram-positive and Gram-negative bacterial strains. The cytotoxic effect of potent compounds on normal cells (V79 and HBL100) was assessed by MTT assay.