Rigid Scaffolds: Synthesis of 2,6‐Bridged Piperazines with Functional Groups in all three Bridges
作者:Donglin Gao、Christian Penno、Bernhard Wünsch
DOI:10.1002/open.202000188
日期:2020.8
conformationally restricted by substituted C2‐ or C3‐bridges across the 2‐ and 6‐position. At first, a three‐step, one‐pot procedure was developed to obtain reproducibly piperazine‐2,6‐diones with various substituents at the N‐atoms in high yields. Three strategies for bridging of piperazine‐2,6‐diones were pursued: 1. The bicyclic mixed ketals 8‐benzyl‐6‐ethoxy‐3‐(4‐methoxybenzyl)‐6‐(trimethylsilyloxy)‐3,8‐diazabicyclo[3
药理活性化合物的活性可以通过以确定的构象呈现药物来增加,该构象恰好适合其靶标的结合口袋。在此,哌嗪支架受取代的 C 2 - 或 C 3构象限制-跨越2-和6-位置的桥梁。首先,开发了三步一锅法以高产率获得在 N 原子上具有各种取代基的可重复哌嗪-2,6-二酮。对哌嗪-2,6-二酮桥接的三种策略进行了探索:1.双环混合缩酮8-苄基-6-乙氧基-3-(4-甲氧基苄基)-6-(三甲基甲硅烷氧基)-3,8-二氮杂双环[3.2 .1]辛烷-2,4-二酮是通过 2-(3,5-二氧哌嗪-2-基)乙酸酯的 Dieckmann 类似环化制备的。2. 哌嗪-2,6-二酮的逐步烯丙基化、硼氢化和氧化生成3-(3,5-二氧哌嗪-2-基)丙醛。而这种醛与碱的反应提供了双环醇 9-苄基-6-羟基-3-(4-甲氧基苄基)-3,9-二氮杂双环[3.3.1]壬烷-2,4-二酮,产率仅为 10% ,相应的亚磺酰亚胺与碱反应得到N-