Synthesis and Dopamine Receptor Affinities of <i>N</i>-Alkyl-11-hydroxy-2-methoxynoraporphines: <i>N</i>-Alkyl Substituents Determine D1 versus D2 Receptor Selectivity
作者:Yu-Gui Si、Matthew P. Gardner、Frank I. Tarazi、Ross J. Baldessarini、John L. Neumeyer
DOI:10.1021/jm701045j
日期:2008.2.1
We developed a procedure to synthesize a series of N-alkyl-2-methoxy-11-hydroxyhoraporphines from thebaine and evaluated their binding affinities at dopamine D-1 and D-2 receptors in rat forebrain tissue. At D-2 receptors, the most potent 10,11-catechol-aporphine was (R)-(-)-2-methoxy-N-n-propylnorapomorphine (D-2, K-i = 1.3 nM; D-1, K-i = 6450 nM), and the most selective and potent 11-monohydroxy aporphine was (R)-(-)-2-methoxy-11-hydroxy-N-n-propylnoraporphine (D-2, K-i = 44 nM; D-1, K-i = 1690 nM). In contrast, the N-methyl congeners (R)-(-)-2-methoxy-11-hydroxy: N-methyl-aporphine (D-1 vs D-2, K-i = 46 vs 235 nM) showed higher D-1 than D2 affinity, indicating that N-alkyl substituents have major effects on D2 affinity and D-2/D-1 selectivity in such 2-methoxy-11-monohydroxy-substituted aporphines.