Macozinone

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) remains a major global health problem and new therapeutic antitubercular agents are urgent needed. Among the novel antituberculosis drugs in the pipeline, Benzothiazinones (BTZs) are among the most potent antituberculosis agents against both drug-susceptible and multidrug-resistant (MDR) tuberculosis. Our group has focused on structural modifications of the side chain at C-2 position of the BTZ core and WAP-2101/2102 with excellent in vitro activity were discovered in our lab. However, the severe in vivo toxicity was observed during subsequent acute toxicity evaluation. Herein, a series of novel N-(amino)piperazinyl benzothiazinone derivatives were designed and synthesized as new anti-TB agents to reduce the in vivo toxicity. Our results show that majority of them exhibit the same potent or comparable activity against both MTB H₃₇Rv and MDR-MTB strains (MIC: 4.00 - <1 ng/mL) as PBTZ169. Especially, compound 2c with low cardiac toxicity, low cell cytotoxicity and acceptable oral pharmacokinetic (PK) profiles have low acute toxicity in mice (LD₅₀ > 500 mg/kg), suggesting it may serve as a promising lead compound for further antitubercular drug discovery.

Tuberculosis (TB) is a leading infectious disease with serious antibiotic resistance. The benzothiazinone (BTZ) scaffold PBTZ169 kills Mycobacterium tuberculosis (Mtb) through the inhibition of the essential cell wall enzyme decaprenylphosphoryl-β-D-ribose 2'-oxidase (DprE1). PBTZ169 shows anti-TB potential in animal models and pilot clinical tests. Although highly potent, the BTZ type DprE1 inhibitors in general show extremely low aqueous solubility, which adversely affects the drug-like properties. To improve the compounds physicochemical properties, we generated a series of BTZ analogues. Several optimized compounds had MIC values against Mtb lower than 0.01 µM. The representative compound 37 displays improved solubility and bioavailability compared to the lead compound. Additionally, compound 37 shows Mtb-killing ability in an acute infection mouse model.