Synthesis and Structure-Activity Relationships of Tambjamines and B-Ring Functionalized Prodiginines as Potent Antimalarials

J Med Chem. 2015 Sep 24;58(18):7286-309. doi: 10.1021/acs.jmedchem.5b00560. Epub 2015 Sep 10.

Abstract

Synthesis and antimalarial activity of 94 novel bipyrrole tambjamines (TAs) and a library of B-ring functionalized tripyrrole prodiginines (PGs) against a panel of Plasmodium falciparum strains are described. The activity and structure-activity relationships demonstrate that the ring-C of PGs can be replaced by an alkylamine, providing for TAs with retained/enhanced potency. Furthermore, ring-B of PGs/TAs can be substituted with short alkyl substitutions at either 4-position (replacement of OMe) or 3- and 4-positions without impacting potency. Eight representative TAs and two PGs have been evaluated for antimalarial activity against multidrug-resistant P. yoelii in mice in the dose range of 5-100 mg/kg × 4 days by oral administration. The KAR425 TA offered greater efficacy than previously observed for any PG, providing 100% protection to malaria-infected mice until day 28 at doses of 25 and 50 mg/kg × 4 days, and was also curative in this model in a single oral dose (80 mg/kg). This study presents the first account of antimalarial activity in tambjamines.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antimalarials / chemistry*
  • Antimalarials / pharmacology
  • Antimalarials / toxicity
  • Drug Resistance, Multiple
  • Female
  • Hep G2 Cells
  • Humans
  • Malaria / drug therapy
  • Malaria / parasitology
  • Mice
  • Plasmodium falciparum / drug effects
  • Plasmodium yoelii
  • Pyrroles / chemistry*
  • Pyrroles / pharmacology
  • Pyrroles / toxicity
  • Structure-Activity Relationship

Substances

  • Antimalarials
  • Pyrroles