Design, synthesis, and biological evaluation of structurally constrained hybrid analogues containing ropinirole moiety as a novel class of potent and selective dopamine D3 receptor ligands.

Two series of hybrid analogues were designed, synthesized, and evaluated as a novel class of selective ligands for the dopamine D3 receptor. Binding affinities of target compounds were determined (using the method of radioligand binding assay). Compared to comparator agent BP897, compounds 2a and 2c were found to demonstrate a considerable binding affinity and selectivity for D3 receptor, and especially compound 2h was similarly potent and more selective D3R ligand than BP897, a positive reference. Thus, they may provide valuable information for the discovery and development of highly potent dopamine D3 receptor ligands with outstanding selectivity.