Discovery of novel positive allosteric modulators of the α7 nicotinic acetylcholine receptor: Scaffold hopping approach.

Abstract

The paper focuses on the scaffold hopping-based discovery and characterization of novel nicotinic alpha 7 receptor positive modulator (α7 nAChR PAM) ligands around the reference molecule (A-867744). First, substantial efforts were carried out to assess the importance of the various pharmacophoric elements on the invitro potency (SAR evaluation) by chemical modifications. Subsequently, several new derivatives with versatile, heteroaromatic central cores were synthesized and characterized. A promising, pyrazole-containing new chemotype with good physicochemical and invitro parameters was identified. Retrospective analysis based on homology modeling was also carried out. Besides its favorable invitro characteristics, the most advanced derivative 69 also showed invivo efficacy in a rodent model of cognition (scopolamine-induced amnesia in the mouse place recognition test) and acceptable pharmacokinetic properties. Based on the invivo data, the resulting molecule with advanced drug-like characteristics has the possibility to improve cognitive performance in a biologically relevant dose range, further strengthening the view of the supportive role of α7 nACh receptors in the cognitive processes.