Synthesis of some 1-(3-hydroxy-4-methoxybenzyl)-2-alkyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinolines and their binding affinities to DA receptor subtypes

Article abstract of DOI:10.1016/0223-5234(94)90126-0

1-(3-hydroxy-4-methoxybenzyl)-2-alkyl-6,7-methylenedioxytetrahydroisoquinolines (3a-c), derived from the D₁ selective antagonist S-bulbocapnine by cleavage of the bond between the 2 aromatic moieties, have been synthesized and their in vitro affinity towards D₁ and D₂ receptors evaluated.Of the compounds tested, the 2-methyl derivative 3a while showing poor affinity towards D₁ receptors was able to inhibit the D₂ radioligand 3H-raclopride binding by 60percent at 10^-5 M.Conformational analysis allows reasonable explanations of the loss of D₁-affinity of 3a with respect to the model. substituted 1-(3-hydroxy-4-methoxybenzyl)-6,7-methylenedioxytetrahydroisoquinoline / D₁ and D₂ receptor binding / bulbocapnine conformational analysis