Improved Phenoxyalkylbenzimidazoles with Activity against Mycobacterium tuberculosis Appear to Target QcrB.

The phenoxy alkyl benzimidazoles (PABs) have good antitubercular activity. We expanded our structure-activity relationship studies to determine the core components of PABs required for activity. The most potent compounds had minimum inhibitory concentrations against Mycobacterium tuberculosis in the low nanomolar range with very little cytotoxicity against eukaryotic cells as well as activity against intracellular bacteria.

Identification of Phenoxyalkylbenzimidazoles with Antitubercular Activity.

We conducted an evaluation of the phenoxyalkylbenzimidazole series based on the exemplar 2-ethyl-1-(3-phenoxypropyl)-1H-benzo[d]imidazole for its antitubercular activity. Four segments of the molecule were examined systematically to define a structure-activity relationship with respect to biological activity. Compounds had submicromolar activity against Mycobacterium tuberculosis; the most potent compound had a minimum inhibitory concentration (MIC) of 52 nM and was not cytotoxic against eukaryotic cells (selectivity index = 523).

The 4-aminopiperidine series has limited anti-tubercular and anti-staphylococcus aureus activity.

Background: Tuberculosis (TB) caused by Mycobacterium tuberculosis is the leading cause of death from a bacterial infection. The 4-aminopiperidine (PIP) series has been reported as having anti-bacterial activity against M. tuberculosis.

Synthesis and anti-tubercular activity of 3-substituted benzo[b]thiophene-1,1-dioxides.

We demonstrated that the 3-substituted benzothiophene-1,1-dioxide class of compounds are effective inhibitors of Mycobacterium tuberculosis growth under aerobic conditions. We examined substitution at the C-3 position of the benzothiophene-1,1-dioxide series systematically to delineate structure-activity relationships influencing potency and cytotoxicity. Compounds were tested for inhibitory activity against virulent M.