Continued optimization of the MLPCN probe ML071 into highly potent agonists of the hM1 muscarinic acetylcholine receptor

This Letter describes the continued optimization of the MLPCN probe molecule ML071. After introducing numerous cyclic constraints and novel substitutions throughout the parent structure, we produced a number of more highly potent agonists of the M-1 mACh receptor. While many novel agonists demonstrated a promising ability to increase soluble APP alpha release, further characterization indicated they may be functioning as bitopic agonists. These results and the implications of a bitopic mode of action are presented. (C) 2012 Elsevier Ltd. All rights reserved.