MF-5112

The screening of an in‐house quinolones library against Mycobacterium tuberculosis (Mtb) H37Rv, followed by a first cycle of optimization, yielded 6‐hydrogen‐8‐methyl derivatives endowed with good potency. The antitubercular activity also encompassed the bacteria in a non‐replicating state (NRP‐TB) with minimum inhibitory concentration values lower than those of the reference agent, moxifloxacin. Among the best compounds, 11w and 11ai, characterized by a properly substituted piperidine at the C‐7 position, were active against single‐drug‐resistant (SDR‐TB) Mtb strains, maintaining overall good potency also against ciprofloxacin‐resistant Mtb. This study expands the body of SAR around antitubercular quinolones leading to reconsider the role played by the usual fluorine atom at the C‐6 position. Further elaboration of the 6‐hydrogen‐8‐methylquinolone scaffold, with a particular focus on the C‐7 position, is expected to give even more potent congeners holding promise for shortening the current anti‐TB regimen.