Discovery of selective dopamine D3 ligands: I. Dimeric 2-[4-(3-aminopropoxy)phenyl]benzimidazole antagonists

A novel series of dimeric 2-[4-(3-aminopropoxy)phenyl]benzimidazole dopamine (DA) D3 receptor antagonists has been discovered. Most of the dimeric structure is needed for DA binding activity; however, a second basic nitrogen atom is not required. A representative compound had no effects on DA synthesis in rat brain but inhibited spontaneous locomotor activity in mice and stimulated locomotor activity in habituated rats.