Design, synthesis, and evaluation of potent and selective ligands for the dopamine 3 (D3) receptor with a novel in vivo behavioral profile

A series of compounds structurally related to pramipexole were designed, synthesized, and evaluated as ligands for the dopamine 3 (D-3) receptor. Compound 12 has a K-i value of 0.41 nM to D3 and a selectivity of > 30000- and 800-fold over the D-1-like and D-2 receptors, respectively. Our in vivo functional assays showed that this compound is a partial agonist at the D-3 receptor with no detectable activity at the D-2 receptor.