2. Academic Validation
  3. Repositioning Antitubercular 6-Nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazoles for Neglected Tropical Diseases: Structure-Activity Studies on a Preclinical Candidate for Visceral Leishmaniasis

Repositioning Antitubercular 6-Nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazoles for Neglected Tropical Diseases: Structure-Activity Studies on a Preclinical Candidate for Visceral Leishmaniasis

  • J Med Chem. 2016 Mar 24;59(6):2530-50. doi: 10.1021/acs.jmedchem.5b01699.
Andrew M Thompson 1,  Patrick D O'Connor 1,  Adrian Blaser 1,  Vanessa Yardley 2,  Louis Maes 3,  Suman Gupta 4,  Delphine Launay 5,  Denis Martin 5,  Scott G Franzblau 6,  Baojie Wan 6,  Yuehong Wang 6,  Zhenkun Ma 7,  William A Denny 1
Affiliations

Affiliations

  • 1 Auckland Cancer Society Research Centre, School of Medical Sciences, The University of Auckland , Private Bag 92019, Auckland 1142, New Zealand.
  • 2 Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine , Keppel Street, London WC1E 7HT, United Kingdom.
  • 3 Laboratory for Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp , Universiteitsplein 1, B-2610 Antwerp, Belgium.
  • 4 Division of Parasitology, CSIR-Central Drug Research Institute , Lucknow 226031, India.
  • 5 Drugs for Neglected Diseases Initiative, 15 Chemin Louis Dunant, 1202 Geneva, Switzerland.
  • 6 Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago , 833 South Wood Street, Chicago, Illinois 60612, United States.
  • 7 Global Alliance for TB Drug Development, 40 Wall Street, New York 10005, United States.
PMID: 26901446 DOI: 10.1021/acs.jmedchem.5b01699
Abstract

6-Nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazole derivatives were initially studied for tuberculosis within a backup program for the clinical trial agent pretomanid (PA-824). Phenotypic screening of representative examples against kinetoplastid diseases unexpectedly led to the identification of DNDI-VL-2098 as a potential first-in-class drug candidate for visceral leishmaniasis (VL). Additional work was then conducted to delineate its essential structural features, aiming to improve solubility and safety without compromising activity against VL. While the 4-nitroimidazole portion was specifically required, several modifications to the aryloxy side chain were well-tolerated e.g., exchange of the linking oxygen for nitrogen (or piperazine), biaryl extension, and replacement of phenyl rings by pyridine. Several less lipophilic analogues displayed improved aqueous solubility, particularly at low pH, although stability toward liver microsomes was highly variable. Upon evaluation in a mouse model of acute Leishmania donovani Infection, one phenylpyridine derivative (37) stood out, providing efficacy surpassing that of the original preclinical lead.

Figures