1,3-Diamino-6,7-dimethoxyisoquinoline derivatives as potential .alpha.1-adrenoceptor antagonists
作者:Jon Bordner、Simon F. Campbell、Michael J. Palmer、Michael S. Tute
DOI:10.1021/jm00400a026
日期:1988.5
kcal/mol) between the protonated quinazoline and the receptor protein. None of the isoquinolines (2) proved to be effective antihypertensive agents in rats even when administered at relatively high doses (10 mg/kg). These results support the hypothesis that the antihypertensive activity of prazosin, doxazosin, and related derivatives derives solely from alpha 1-adrenoceptor blockade.
用LDA处理2-甲基-4,5-二甲氧基苄腈(3),然后与N,N-二取代的氰胺反应,得到一系列的1,3-二氨基-6,7-二甲氧基异喹啉(2),对其进行评估α-肾上腺素受体结合亲和力和降压活性。1-氨基-3-(二甲基氨基)-6,7-二甲氧基异喹啉(4)对α1-肾上腺素受体没有明显的亲和力(Ki远大于10(-6)M),而相应的3-(2-呋喃基哌嗪- 1-yl)类似物(8; Ki = 1.6 X 10(-7)M)的效力比哌唑嗪低约1000倍。pKa数据显示,在生理pH值下会发生4的N-2质子化(34%)(pKa = 7.1),这与8.HCl的X射线晶体学分析一致。质子化4与相应的喹啉和喹唑啉阳离子质子化后的正电荷分布的比较证实,N-1质子化是这些杂环核有效结合至α1-肾上腺素受体所必需的。计算机辅助比较8和哌唑嗪的X射线结构表明,α1-肾上腺素受体结合能的4.0 kcal / mol差异主要是由于