Challenges in the development of an M4 PAM preclinical candidate: The discovery, SAR, and in vivo characterization of a series of 3-aminoazetidine-derived amides

Bioorg Med Chem Lett. 2017 Jul 1;27(13):2990-2995. doi: 10.1016/j.bmcl.2017.05.014. Epub 2017 May 6.

Abstract

This letter details the continued chemical optimization of a novel series of M4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core by incorporating a 3-amino azetidine amide moiety. The analogs described within this work represent the most potent M4 PAMs reported for this series to date. The SAR to address potency, clearance, subtype selectivity, CNS exposure, and P-gp efflux are described. This work culminated in the discovery of VU6000918, which demonstrated robust efficacy in a rat amphetamine-induced hyperlocomotion reversal model at a minimum efficacious dose of 0.3mg/kg.

Keywords: Azetidine; M(4); Muscarinic acetylcholine receptor; Positive allosteric modulator (PAM); Schizophrenia.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Regulation / drug effects
  • Amides / chemical synthesis
  • Amides / chemistry
  • Amides / pharmacology*
  • Animals
  • Azetidines / chemical synthesis
  • Azetidines / chemistry
  • Azetidines / pharmacology*
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Humans
  • Molecular Structure
  • Rats
  • Receptor, Muscarinic M4 / antagonists & inhibitors*
  • Structure-Activity Relationship

Substances

  • Amides
  • Azetidines
  • Receptor, Muscarinic M4