MOLECULAR REQUIREMENTS OF THE ACTIVE SITESOF THE CHOLINERGIC RECEPTORSXI - Synthesis and biological evaluation of isomuscarine and itsisomers

The synthesis of isomuscarine (lI c) and ol its threeisomers is described. Their structure were establisked on the basis olN.M.R. and I.R. data.unlike the dioxolane (l), lrom which they are lormally derived bysubstituting the oxygen in position 3 by a CHOH group, the isomuscarinesare completely devoid of cholinergic activity. This result is explained bythe impossibility ol the corresponding receptor site of accepting a grouplarger than the ether oxygen. Interactions ol the onium and C-7 methylgroups are assumed to be the driving lorces for binding with the muscarinicreceptor while a dipole-dipole interaction for oxygenated functions is proposed