5, 6-Dimethoxy-2-(N-dipropyl)-aminoindan (3, PNU-99194A) was found to be a selective dopamine D3 receptor antagonist with potential antipsychotic properties in animal models. To investigate the effects of nitrogen substitution on structure-activity relationships, a series of 5, 6-dimethoxy-N-alkyl-and N-alkylaryl-substituted 2-aminoindans were synthesized and evaluated in vitro for binding affinity and metabolic stability. The results indicate that ...