| abstract |
Di-N-substituted piperazine or 1,4 di-substituted piperadine compounds in accordance with formula I (including all isomers, salts, esters, and solvates) wherein R, R1, R2, R3, R4, R21, R27, R28, X, Y, and Z are as defined herein are muscarinic antagonists useful for treating cognitive disorders such as Alzheimer's disease. Pharmaceutical compositions and methods of preparation are also disclosed. Also disclosed are synergistic combinations of compounds of the above formula or other compounds capable of enhancing acetylcholine release with acetylcholinesterase inhibitors. |