title: Synthesis of 2-(2,3-dimethoxyphenyl)-4-(aminomethyl)imidazole analogues and their binding affinities for dopamine D(2) and D(3) receptors.
abstract: A series of 2-(2,3-dimethoxyphenyl)-4-(aminomethyl)imidazole derivatives was prepared and their affinity for dopamine D(2) and D(3) receptors was measured using in vitro binding assays. Several oxadiazole analogues were also prepared and tested for their affinity for dopamine D(2) and D(3) receptors. The results of receptor binding studies indicated that the incorporation of an imidazole moiety between the phenyl ring and the basic nitrogen did not significantly increase the selectivity for dopamine D(3) receptors, whereas the incorporation of an oxadiazole at the same region resulted in a total loss of affinity for both dopamine receptor subtype binding sites. The most selective compound in this series is 2-(5-bromo-2,3-dimethoxyphenyl)-4-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinomethyl)imidazole (5i), which has a D(3) receptor affinity of 21nM and a 7-fold selectivity for D(3) versus D(2) receptors. The binding affinity for sigma(1) and sigma(2) receptors was also measured, and the results showed that several analogues were selective sigma(1) receptor ligands.
authors.affiliation: Department of Radiology-PET Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.forename: R R
authors.initials: RR
authors.lastname: Luedtke
authors.forename: R A
authors.initials: RA
authors.lastname: Freeman
authors.forename: L
authors.initials: L
authors.lastname: Wu
authors.forename: R H
authors.initials: RH
authors.lastname: Mach
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006168:Guinea Pigs; D007093:Imidazoles; D007546:Isoquinolines; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3; D017480:Receptors, sigma / Q000378:metabolism; D013329:Structure-Activity Relationship; D044005:Tetrahydroisoquinolines; D000097605:Sigma-1 Receptor
chemical_list: D014150:Antipsychotic Agents; D007093:Imidazoles; D007546:Isoquinolines; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D017480:Receptors, sigma; D044005:Tetrahydroisoquinolines; D000097605:Sigma-1 Receptor; C448861:2-(5-bromo-2,3-dimethoxyphenyl)-4-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinomethyl)imidazole; C106107:sigma-2 receptor