Discovery, characterization and biological evaluation of a novel (R)-4,4-difluoropiperidine scaffold as dopamine receptor 4 (D4R) antagonists

[Display omitted] Herein, we report the synthesis and structure–activity relationship of a novel series of (R)-4,4-difluoropiperidine core scaffold as dopamine receptor 4 (D4) antagonists. A series of compounds from this scaffold are highly potent against the D4 receptor and selective against the other dopamine receptors. In addition, we were able to confirm the active isomer as the (R)-enantiomer via an X-ray crystal structure.