Imidazolopiperazines: lead optimization of the second-generation antimalarial agents

J Med Chem. 2012 May 10;55(9):4244-73. doi: 10.1021/jm300041e. Epub 2012 Apr 23.


On the basis of the initial success of optimization of a novel series of imidazolopiperazines, a second generation of compounds involving changes in the core piperazine ring was synthesized to improve antimalarial properties. These changes were carried out to further improve the potency and metabolic stability of the compounds by leveraging the outcome of a set of in vitro metabolic identification studies. The optimized 8,8-dimethyl imidazolopiperazine analogues exhibited improved potency, in vitro metabolic stability profile and, as a result, enhanced oral exposure in vivo in mice. The optimized compounds were found to be more efficacious than the current antimalarials in a malaria mouse model. They exhibit moderate oral exposure in rat pharmacokinetic studies to achieve sufficient multiples of the oral exposure at the efficacious dose in toxicology studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimalarials / chemical synthesis
  • Antimalarials / chemistry
  • Antimalarials / pharmacokinetics
  • Antimalarials / pharmacology*
  • Biological Availability
  • Caco-2 Cells
  • Humans
  • Imidazoles / chemical synthesis
  • Imidazoles / chemistry
  • Imidazoles / pharmacokinetics
  • Imidazoles / pharmacology*
  • Malaria, Falciparum / drug therapy*
  • Malaria, Falciparum / parasitology
  • Mice
  • Mice, Inbred BALB C
  • Piperazines / chemical synthesis
  • Piperazines / chemistry
  • Piperazines / pharmacokinetics
  • Piperazines / pharmacology*
  • Plasmodium falciparum / drug effects*
  • Plasmodium falciparum / metabolism
  • Rats
  • Rats, Wistar
  • Structure-Activity Relationship


  • Antimalarials
  • Imidazoles
  • Piperazines