The synthesis of 5-(dipropylamino)-5, 6-dihydro-4H-imidazo [4l5, l-ij] quinolin-2 (lH)-one (5), a potent dopamine D2 agonist showing high dopamine/serotonin (5HT1~) selectivity, is described. Dopaminergic activity is associated with the (R)-enantiomer of 5; the (SI- enantiomer shows no dopaminergic activity. A series of analogues where the imidezolone ring wan modified to various 5 or 6membered heterocyclic ringe were prepared. Some of ...