Substituted pyrazoles as novel selective ligands for the human dopamine D4 receptor

Abstract Two novel series of 3-(heterocyclylmethyl)pyrazoles have been synthesised and evaluated as ligands for the human dopamine D 4 receptor. Compounds in series I (exemplified by 8k ) have a phenyl ring joined to the 4-position of the pyrazole while those in series II (exemplified by 15j ) have a 5-phenyl ring linked by a saturated chain to the 4-position of the pyrazole. Both series supplied compounds with excellent affinity for the human D 4 and good selectivity over other dopamine receptors. Excellent selectivity over calcium, sodium, and potassium ion channels was also achieved.