Synthesis and structure-activity relationships of new 2-phenoxybenzamides with antiplasmodial activity

Theresa Hermann, Patrick Hochegger, Johanna Dolensky, Werner Seebacher, Eva Maria Pferschy-Wenzig, Robert Saf, Marcel Kaiser, Pascal Mäser, Robert Weis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The 2-phenoxybenzamide 1 from the Medicines for Malaria Venture Malaria Box Project has shown promising multi-stage activity against different strains of P. falciparum. It was successfully synthesized via a retrosynthetic approach. Subsequently, twenty-one new derivatives were prepared and tested for their in vitro activity against blood stages of the NF54 strain of P. falciparum. Several insights into structure-activity relationships were revealed. The antiplasmodial activity and cytotoxicity of compounds strongly depended on the substitution pattern of the anilino partial structure as well as on the size of substituents. The diaryl ether partial structure had further impacts on the activity. Additionally, several physicochemical and pharmacokinetic parameters were calculated (log P, log D7.4 and ligand efficiency) or determined experimentally (passive permeability and CYP3A4 inhibition). The tert-butyl-4-{4-[2-(4-fluorophenoxy)-3-(trifluoromethyl)benzamido]phenyl}piperazine-1-carboxylate possesses high antiplasmodial activity against P. falciparum NF54 (PfNF54 IC50 = 0.2690 µM) and very low cytotoxicity (L-6 cells IC50 = 124.0 µM) resulting in an excellent selectivity index of 460. Compared to the lead structure 1 the antiplasmodial activity was improved as well as the physicochemical and some pharmacokinetic parameters.

Original languageEnglish
Article number1109
Issue number11
Publication statusPublished - Nov 2021


  • 2-phenoxybenzamides
  • Antimalarial
  • CYP3A4 inhibition
  • Plasmodium falciparum

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery


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