Synthesis of Potent and Selective Dopamine D4 Antagonists as Candidate Radioligands.

Abstract A series of dopamine D4 antagonists was synthesized and evaluated as potential candidates for development as positron emission tomography (PET) radioligands. All new compounds display high affinity and selectivity for the D4 receptors and compounds 5b, 5d, and 5e were identified as candidates for radioligand development.