Tetrahydropyrazolo[1,5-a]pyrimidine-3-carboxamide and N-benzyl-6',7'-dihydrospiro[piperidine-4,4'-thieno[3,2-c]pyran] analogues with bactericidal efficacy against Mycobacterium tuberculosis targeting MmpL3

PLoS One. 2013 Apr 17;8(4):e60933. doi: 10.1371/journal.pone.0060933. Print 2013.


Mycobacterium tuberculosis is a major human pathogen and the causative agent for the pulmonary disease, tuberculosis (TB). Current treatment programs to combat TB are under threat due to the emergence of multi-drug and extensively-drug resistant TB. As part of our efforts towards the discovery of new anti-tubercular leads, a number of potent tetrahydropyrazolo[1,5-a]pyrimidine-3-carboxamide (THPP) and N-benzyl-6',7'-dihydrospiro[piperidine-4,4'-thieno[3,2-c]pyran] (Spiro) analogues were recently identified against Mycobacterium tuberculosis and Mycobacterium bovis BCG through a high-throughput whole-cell screening campaign. Herein, we describe the attractive in vitro and in vivo anti-tubercular profiles of both lead series. The generation of M. tuberculosis spontaneous mutants and subsequent whole genome sequencing of several resistant mutants identified single mutations in the essential mmpL3 gene. This 'genetic phenotype' was further confirmed by a 'chemical phenotype', whereby M. bovis BCG treated with both the THPP and Spiro series resulted in the accumulation of trehalose monomycolate. In vivo efficacy evaluation of two optimized THPP and Spiro leads showed how the compounds were able to reduce >2 logs bacterial cfu counts in the lungs of infected mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antitubercular Agents / chemistry
  • Antitubercular Agents / pharmacokinetics
  • Antitubercular Agents / pharmacology*
  • Antitubercular Agents / therapeutic use
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / metabolism
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacokinetics
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology*
  • Bridged Bicyclo Compounds, Heterocyclic / therapeutic use
  • Chromatography, Thin Layer
  • Cord Factors
  • Disease Models, Animal
  • Dogs
  • Drug Resistance, Bacterial
  • Genotype
  • Hep G2 Cells
  • Humans
  • Kinetics
  • Mice
  • Microbial Sensitivity Tests
  • Microbial Viability / drug effects
  • Mutation / genetics
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / isolation & purification
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacokinetics
  • Pyrazoles / pharmacology*
  • Pyrazoles / therapeutic use
  • Rats
  • Spiro Compounds / chemistry
  • Spiro Compounds / pharmacokinetics
  • Spiro Compounds / pharmacology*
  • Spiro Compounds / therapeutic use
  • Treatment Outcome
  • Tuberculosis / drug therapy
  • Tuberculosis / microbiology


  • Antitubercular Agents
  • Bacterial Proteins
  • Bridged Bicyclo Compounds, Heterocyclic
  • Cord Factors
  • Pyrazoles
  • Spiro Compounds
  • trehalose monomycolate