SYNTHESIS OF AZABICYCLIC PYRAZINE DERIVATIVES AS MUSCARINIC AGONISTS AND THE PREPARATION OF A CHLOROPYRAZINE ANALOG WITH FUNCTIONAL SELECTIVITY AT SUBTYPES OF THE MUSCARINIC RECEPTOR

The synthesis of quinuclidine and azanorbornyl pyrazine derivatives has yielded highly potent and efficacious muscarinic agonists; chloro-substitution in the pyrazine ring of the quinuclidine analogue resulted in the formation of a derivative with both enantiomers displaying partial agonist character but, more importantly, functional selectivity at the M1, M2 and M3 sub-types of the muscarinic receptor.