合成了标题化合物,并研究了它们在溶液中(NMR和DFT),在气相(DFT)中以及对于其中一些在固态(X射线)中的结构和构象行为。使用可变温度NMR光谱确定八元环的构象平衡和构象变化的活化能。聚结效应被分配给手性基态构象的外消旋化,该手性基态构象在38–100 kJ mol –1的范围内具有环反转势垒,这取决于两个强构象约束条件的相对设置:苯并环化和酰胺功能。第二个构象过程,即苯并[ c ]偶氮素-3-one,苯并[观察到d ]偶氮星-2-酮和苯并[ d ]偶氮星-4-酮。通过分析实验数据和计算得出的NMR数据,阐明了溶液中观察到的构象异构体的性质。结合先前关于(Z,Z)-环辛二烯及其苯并类似物的实验和理论数据讨论了目前的结果。
Conformations and Conformational Processes of Hexahydrobenzazocines by NMR and DFT Studies
作者:Bogdan Musielak、Tad A. Holak、Barbara Rys
DOI:10.1021/acs.joc.5b01687
日期:2015.9.18
Conformationalprocesses that occur in hexahydrobenzazocines have been studied with the 1H and 13C dynamic nuclear magnetic resonance (DNMR) spectroscopy. The coalescence effects are assigned to two different conformationalprocesses: the ring-inversion of the ground-state conformations and the interconversion between two different conformers. The barriers for these processes are in the range of 42–52
were synthesized, and their structure and conformational behavior in solution (NMR and DFT), in the gas phase (DFT), and, for some of them, in the solid state (X-ray) were investigated. The variable-temperature NMR spectra were employed to determine the conformational equilibria and the activation energy of the conformational changes of the eight-memberedring. The coalescence effects are assigned to
合成了标题化合物,并研究了它们在溶液中(NMR和DFT),在气相(DFT)中以及对于其中一些在固态(X射线)中的结构和构象行为。使用可变温度NMR光谱确定八元环的构象平衡和构象变化的活化能。聚结效应被分配给手性基态构象的外消旋化,该手性基态构象在38–100 kJ mol –1的范围内具有环反转势垒,这取决于两个强构象约束条件的相对设置:苯并环化和酰胺功能。第二个构象过程,即苯并[ c ]偶氮素-3-one,苯并[观察到d ]偶氮星-2-酮和苯并[ d ]偶氮星-4-酮。通过分析实验数据和计算得出的NMR数据,阐明了溶液中观察到的构象异构体的性质。结合先前关于(Z,Z)-环辛二烯及其苯并类似物的实验和理论数据讨论了目前的结果。