Design and development of new class of Mycobacterium tuberculosisl-alanine dehydrogenase inhibitors.

Mycobacterium tuberculosisl-alanine dehydrogenase (MTB l-AlaDH) is one of the important drug targets for treating latent/persistent tuberculosis. In this study we used crystal structure of the MTB l-AlaDH bound with cofactor NAD(+) as a structural framework for virtual screening of our in-house database to identified new classes of l-AlaDH inhibitor. We identified azetidine-2,4-dicarboxamide derivative as one of the potent inhibitor with IC50 of 9.22±0.72µM. Further lead optimization by synthesis leads to compound 1-(isonicotinamido)-N(2),N(4)-bis(benzo[d]thiazol-2-yl)azetidine-2,4-dicarboxamide (18) with l-AlaDH IC50 of 3.83±0.12µM, 2.0log reduction in nutrient starved dormant MTB model and MIC of 11.81µM in actively replicative MTB.