Bis(het)aryl-1,2,3-triazole quinuclidines as α7 nicotinic acetylcholine receptor ligands: Synthesis, structure affinity relationships, agonism activity, [18F]-radiolabeling and PET study in rats

Eur J Med Chem. 2019 Oct 1:179:449-469. doi: 10.1016/j.ejmech.2019.06.049. Epub 2019 Jun 27.

Abstract

In this paper we describe the design and synthesis of bis(Het)Aryl-1,2,3-triazole quinuclidine α7R ligands using an efficient three-step sequence including a Suzuki-Miyaura cross coupling reaction with commercially available and home-made boron derivatives. The exploration of SAR required the preparation of uncommon boron derivatives. Forty final drugs were tested for their ability to bind the target and nine of them exhibited Ki values below nanomolar concentrations. The best scores were always obtained when the 5-phenyl-2-thiophenyl core was attached to the triazole. The selectivity of these compounds towards the nicotinic α4β2 and serotoninergic 5HT3 receptors was assessed and their brain penetration was quantified by the preparation and in vivo evaluation of two [18F] radiolabelled derivatives. It can be expected from our results that some of these compounds will be suitable for further developments and will have effects on cognitive disorders.

Keywords: (18)F PET; Agonism; Alpha 7 nicotinic acetylcholine receptor; Quinuclidine; Radiolabeling; SAR; Triazole.

MeSH terms

  • Animals
  • Brain / diagnostic imaging*
  • Brain / metabolism
  • Cell Survival / drug effects
  • Cognition Disorders / drug therapy*
  • Cognition Disorders / metabolism
  • Dose-Response Relationship, Drug
  • Fluorine Radioisotopes / chemistry*
  • Isotope Labeling*
  • Ligands
  • Molecular Structure
  • Nicotinic Agonists / chemical synthesis
  • Nicotinic Agonists / chemistry
  • Nicotinic Agonists / pharmacology*
  • Positron-Emission Tomography*
  • Quinuclidines / chemical synthesis
  • Quinuclidines / chemistry
  • Quinuclidines / pharmacology*
  • Rats
  • Rats, Wistar
  • Structure-Activity Relationship
  • Triazoles / chemical synthesis
  • Triazoles / chemistry
  • Triazoles / pharmacology*
  • Tumor Cells, Cultured
  • alpha7 Nicotinic Acetylcholine Receptor / agonists*
  • alpha7 Nicotinic Acetylcholine Receptor / metabolism

Substances

  • Fluorine Radioisotopes
  • Ligands
  • Nicotinic Agonists
  • Quinuclidines
  • Triazoles
  • alpha7 Nicotinic Acetylcholine Receptor