Discovery of a Selective Allosteric M<sub>1</sub> Receptor Modulator with Suitable Development Properties Based on a Quinolizidinone Carboxylic Acid Scaffold
作者:Scott D. Kuduk、Ronald K. Chang、Christina N. Di Marco、Daniel R. Pitts、Thomas J. Greshock、Lei Ma、Marion Wittmann、Matthew A. Seager、Kenneth A. Koeplinger、Charles D. Thompson、George D. Hartman、Mark T. Bilodeau、William J. Ray
DOI:10.1021/jm200400m
日期:2011.7.14
One approach to ameliorate the cognitive decline in Alzheimer's disease (AD) has been to restore neuronal signaling from the basal forebrain cholinergic system via the activation of the M-1 muscarinic receptor. A number of nonselective M-1 muscarinic agonists have previously shown positive effects on cognitive behaviors in AD patients, but were limited due to cholinergic adverse events thought to be mediated by the activation of the M-2 to M-5 subtypes. One strategy to confer selectivity for M-1 is the identification of positive allosteric modulators, which would target an allosteric site on the M-1 receptor rather than the highly conserved orthosteric acetylcholine binding site. Quinoline carboxylic acids have I been previously identified as highly selective M-1 positive allosteric modulators with good pharmacokinetic and in vivo properties. Herein is described the optimization of a novel quinolizidinone carboxylic acid scaffold with 4-cyanopiperidines being a key discovery in terms of enhanced activity. In particular, modulator 4i gave high plasma free fractions, enhanced central nervous system (CNS) exposure, was efficacious in a rodent in vivo model of cognition, and afforded good physicochemical properties suitable for further preclinical evaluation.