Further characterization of structural requirements for ligands at the dopamine D(2) and D(3) receptor: exploring the thiophene moiety.

The present study describes the synthesis and in vitro pharmacology of a novel series of dopaminergic agents in which the classical phenylethylamine pharmacophore is replaced by a thienylethylamine moiety. In general, the novel compounds showed a moderate affinity for the dopamine (DA) D(2) and D(3) receptors. When the thienylethylamine moiety is fixed in a rigid system, the affinity for the DA receptor is significantly increased. However, in the tricyclic hexahydrothianaphthoxazine structure, the affinity for the DA receptors is diminished.