Synthesis, Activity, Toxicity, and In Silico Studies of New Antimycobacterial N-alkyl Nitrobenzamides as Potential DprE1 Inhibitors

We have developed a family of N-alkyl-nitrobenzamides that exhibit promising antitubercular ac-tivities. These compounds are a simplification of the structure of known inhibitors of DprE1, an essential Mtb enzyme and an emergent anti-TB target. The compounds were obtained by a simple synthetic methodology and their antitubercular, cyto-toxicity and stability were studied. The most active compounds were the 3,5-dinitro and the 3-nitro-5-trifluoromethyl derivatives. Lipophilicity was shown to be a main parameter modulating activity within each family. The most active compound presented MIC of 16 ng/mL and had in-termediate lipophilicities. The activity was also studied in a macrophage model of infection. In this model the compounds with chain lengths of 6 and 12 carbon atoms presented the best results, ex-hibiting activity profiles comparable to isoniazid. Docking studies performed suggested that the fit of our highly active compounds to the DprE1 binding pocket was very similar to the literature compounds. Furthermore, the metrics used in the analysis were able to distinguish between the families of the highly and least active compounds. Assessment of susceptibility over multiple species and computational together with the structure of the compounds are complementary information that supports DprE1 as a likely target of action for this type of compounds.