Structure–activity relationship of dopaminergic halogenated 1-benzyl-tetrahydroisoquinoline derivatives

Abstract

Two series of halogenated 1-benzyl-7-chloro-6-hydroxy-tetrahydroisoquinolines were prepared to explore the influence of each series on the affinity for dopamine receptors. All the compounds displayed a high affinity for D1-like and/or D2-like dopamine receptors in striatal membranes, although they were unable to inhibit [3H]-dopamine uptake in striatal synaptosomes. The halogen placed on the benzylic ring in 1-benzyl-THIQs, compounds of the series 1, 2′-bromobenzyl derivatives with Ki values into the nanomolar range, and the series 2, 2′,4′-dichlorobenzyl-THIQ homologues, proves to be an important factor to modulate affinity at dopamine receptor.