Quinolizidinone Carboxylic Acids as CNS Penetrant, Selective M1 Allosteric Muscarinic Receptor Modulators

Positive allosteric modulation of the M, muscarinic receptor represents an approach to treat the cognitive decline in patients with Alzheimer's disease. Replacement of a quinolone ring system in a quinolone carboxylic acid series of M, modulators with a quinolizidinone bearing a basic amine linkage led to a series of compounds with higher free fraction, enhanced CNS exposure, and improved efficacy in rodent in vivo models of cognition.