Benzo[d]thiazol-2-yl(piperazin-1-yl)methanones as new anti-mycobacterial chemotypes: design, synthesis, biological evaluation and 3D-QSAR studies

Abstract

The benzo[d]thiazol-2-yl(piperazin-1-yl)methanones scaffold has been identified as new anti-mycobacterial chemotypes. Thirty-six structurally diverse benzo[d]thiazole-2-carboxamides have been prepared and subjected to assessment of their potential anti-tubercular activity through in vitro testing against Mycobacterium tuberculosis H₃₇Rv strain and evaluation of cytotoxicity against RAW 264.7 cell lines. Seventeen compounds showed anti-mycobacterial potential having MICs in the low (1–10) μM range. The 5-trifluoromethyl benzo[d]thiazol-2-yl(piperazin-1-yl)methanones emerged to be the most promising resulting in six positive hits (2.35–7.94 μM) and showed low-cytotoxicity (<50% inhibition at 50 μg/mL). The therapeutic index of these hits is 8–64. The quantitative structure activity relationship has been established adopting a statistically reliable CoMFA model showing high prediction (r²_pred=0.718, r²_ncv=0.995).