6-(4-Benzylpiperazin-1-yl)benzodioxanes as selective ligands at cloned primate dopamine D4 receptors

A series of novel 6-(4-benzylpiperazin-1-yl)benzodioxanes were prepared and screened at selected dopamine receptor subtypes. 6-(4-[4-Chlorobenzyl]piperazin-1-yl)benzodioxane (2d) had high affinity and selectivity for the D₄ dopamine receptor subtype and was identified as a D₄ antagonist via its attenuation of dopamine-induced GTPγ³⁵S binding at the D₄ receptor.