Abstract: The present invention relates to substituted pyrrolidinone compounds of formula 1, wherein n is 0 or 1; Aza is a heterocycle optionally substituted with C1-4 alkyl, or C1-4 alkyl substituted with a heterocycle, which represents a saturated or unsaturated five- or six-membered ring having nitrogen(s) as a heteroatom, which are muscarinic acetylcholine receptor agonists and useful as nootropics and therapeutic agents for cerebral neural diseases such as Alzheimer's disease; and pharmaceutically acceptable salts thereof; processes for the preparation thereof; and pharmaceutical compositions comprising these compounds or salts.