Abstract
This Letter describes the synthesis and optimization of a series of heteroaryl-pyrrolidinone positive allosteric modulators (PAMs) of the muscarinic acetylcholine receptor M(1) (mAChR M(1)). Through the continued optimization of M(1) PAM tool compound VU0453595, with a focus on replacement of the 6,7-dihydro-5H-pyrrolo[3,4-b]pyridin-5-one with a wide variety of alternative 4,5-dihydropyrrolo-fused heteroaromatics, the generation of M(1) PAMs with structurally novel chemotypes is disclosed. Two compounds from these subseries, 8b (VU6005610) and 20a (VU6005852), show robust selectivity for the M(1) mAChR, and no M(1) agonism. Both compounds have favorable preliminary PK profiles in vitro;8b additionally demonstrates high brain exposure in a rodent IV cassette model.