Interactive SAR studies: rational discovery of super-potent and highly selective dopamine D3 receptor antagonists and partial agonists.

Starting from dopamine receptor ligand BP897, an interactive drug discovery process leading to heterocyclic bioisosteres is demonstrated. The four step strategy involved a careful optimization of geometric and electronic properties by systematic modification of the attachment points and heteroatoms, respectively. Efficacy tuning by modification of the phenyl substituents led to both D3 partial agonists and full antagonists. The benzothiophenes 3c (FAUC346) and 3d (FAUC365) revealed outstanding D3 affinity and subtype selectivity.