Evolution of Small Molecule Inhibitors of Mycobacterium tuberculosis Menaquinone Biosynthesis

A dire need exists for novel drugs to treat Mycobacterium tuberculosis infection. In an effort to build on our early efforts targeting the MenG enzyme within the menaquinone biosynthetic pathway, we have pursued the optimization of diaryl amide JSF-2911 to address its poor metabolic stability and modest in vitro potency. A hit evolution campaign focused on modification of the amine substructure within this hit compound, resulting in a range of analogues that have been profiled extensively. Among these derivatives, JSF-4536 and JSF-4898 demonstrated significantly improved biological profiles, notably offering submicromolar MIC values versus M. tuberculosis and promising values characterizing the mouse liver microsome stability, aqueous solubility, and mouse pharmacokinetic profile. JSF-4898 enhanced the efficacy of rifampicin in a subacute model of M. tuberculosis infection in mice. The findings suggest a rationale for the further optimization of MenG inhibitors to provide a novel therapeutic strategy to address M. tuberculosis infection.