摘要:
Novel arylpiperazines were identified as alpha(1)-adrenoceptor(BR) subtype-selective antagonists by functional in vitro screening. 3-[4-(ortho-Substituted phenyl)piperazin-1-yl]propylamines were derivatized with N,N-dimethyl anthranilamides, nicotinamides,;as well as carboxamides of quinoline, I,8-naphthyridine, pyrazolo[3,4-b]pyridine, isoxazolo[3,4-b]pyridine, imidazo[4,5-b]pyridine, and pyrazolo[1,5-a]pyrimidines. Strips of rabbit bladder neck were employed as a predictive assay for antagonism in the human lower tract. Rings of rat aorta;a were used as a ''negative screen'' for the test antagonists. Binding to alpha(1)-ARs was relatively sensitive to size and electronic features of the arylpiperazine portion of the antagonists and permissive to these features on the heteroaryl carboxamide side. These structure-affinity findings were exploited to produce nicotinamides (e.g, 13ii and 25x) and pyrazolo[3,4-b]pyridines (e.g. 37f and 37y) ligands with nanomolar affinity at the alpha(1)-AR subtype prevalent in the human lower urinary tract (pA(2) values: 8.8, 10.7, 9.3, and 9.9, respectively) and displaying 2-3 orders of magnitude selectivity over the alpha(1D)-AR.