Conformation Analyses, Dynamic Behavior, and Amide Bond Distortions of Medium-sized Heterocycles. 2. Partially and Fully Reduced 1-Benzazocines, Benzazonines, and Benzazecines
作者:Maryiam Qadir、Jonathan Cobb、Peter W. Sheldrake、Neil Whittall、Andrew J. P. White、King Kuok (Mimi) Hii、Peter N. Horton、Michael B. Hursthouse
DOI:10.1021/jo048117j
日期:2005.3.1
forms of benzo-fused eight- to ten-membered nitrogen heterocycles (1-benzazecines, 1-benzazonines and 1-benzazecines) have been prepared. Conformational features, transannular distances and dynamic behavior were studied using X-ray crystallography and VT NMR spectroscopy. The amide moiety in the nine-membered benzazonine ring 5b favors N-pyramidization, whereas the ten-membered benzazecine 5c adopts
已经制备了部分和完全还原形式的苯并稠合的八元至十元氮杂环(1-苯并ze嗪,1-苯并zon嗪和1-苯并ze嗪)。使用X射线晶体学和VT NMR光谱研究了构象特征,跨环距离和动力学行为。九元苯并zon嗪环5b中的酰胺部分有利于N-金字塔化,而十元苯并ze嗪5c采用酰胺捻。分子力学计算揭示了酰胺捻度(τ)与环稳定性之间的相关性。还发现溶液中杂环的动力学行为取决于酰胺变形的程度和性质。因此,我们得出结论,这些中等大小的杂环的环应变通过酰胺变形得以缓解,这导致了更稳定的结构。