Benzo[d]thiazole-2-carbanilides as new anti-TB chemotypes: Design, synthesis, biological evaluation, and structure-activity relationship

Tuberculosis is the second leading cause of deaths worldwide. The inadequacy of existing drugs to treat TB due to developed resistance and TB-HIV synergism urges for new anti-TB drugs. Seventy-two benzo[d]thiazole-2-carbanilides have been synthesized through CDI-mediated direct coupling of benzo[d]thiazole-2-carboxylic acids with aromatic amines using a three step methodology which includes a green protocol for synthesis of ethyl benzo[d]thiazole-2-carboxylates, precursor of the desired carboxylic acids. The compounds were evaluated in vitro for anti-tubercular activity against M. tuberculosis H37Rv (ATCC27294 strain). Thirty-two compounds exhibiting MIC values in the range of 0.78–6.25 μg/mL (1.9–23 μM) were subjected to cell viability test against RAW 264.7 cell lines and thirty compounds were found to be non-toxic (