Synthesis, functional and binding profile of (R)-apomorphine based homobivalent ligands targeting the dopamine D2 receptor

Bivalent ligands represent useful tools to investigate the phenomenon of GPCR dimerization. We synthesized bivalent ligands based on (R)-apomorphine with variations in spacer length, and assessed these compounds in functional and binding assays at the dopamine D-2 receptor. The results present novel SAR for bivalent ligands targeting the D2R, and identify a relationship for spacer length with ligand potency, efficacy and affinity.