The synthesis of some muscarone analogs has been accomplished and thei
r muscarinic activity has been assayed in three in vitro functional te
sts. The results of such an investigation put in evidence the active r
ole played by the methylene moiety, placed exocyclic to the pentaatomi
c ring, on the interaction of the ligands with the different muscarini
c receptor subtypes. Worth noting is the ileum-atria selectivity displ
ayed by methylene derivative 7.