Clark RD, Berger J, Garg P, Weinhardt KK, Spedding M, Kilpatrick AT, Brown CM, MacKinnon AC. Affinity of 2-(tetrahydroisoquinolin-2-ylmethyl)- and 2-(isoindolin-2-ylmethyl)imidazolines for alpha-adrenoceptors. Differential affinity of imidazolines for the [3H]idazoxan-labeled alpha 2-adrenoceptor vs the [3H]yohimbine-labeled site.
J Med Chem 1990;
33:596-600. [PMID:
2153820 DOI:
10.1021/jm00164a021]
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Abstract
A series of 2-(tetrahydroisoquinolin-2-ylmethyl)- and 2-(isoindolin-2-ylmethyl)imidazolines were prepared and tested for alpha 1- and alpha 2-adrenoceptor affinity with radioligand binding. Several compounds, 5-fluoro-(5h), 5-chloro-(5j), 5,8-dimethoxy- (5r), and 5,8-dimethoxy- (5r),1-methyl- (5s) 2-(tetrahydroisoquinolin-2- ylmethyl)imidazoline, were found to be selective alpha 2-adrenoceptor ligands on the basis of displacement of [3H]yohimbine from rat cerebral cortical membranes. One compound, 2-[(8-chloro tetrahydroisoquinolin-2-yl)methyl]imidazoline (5m), showed a 36-fold difference in affinity for the [3H]idazoxan-labeled alpha 2-adrenoceptor relative to the [3H]yohimbine-labeled site, which may be evidence for alpha 2-adrenoceptor subtypes.
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