2-Isoxazolidineethanols: An NMR study of the effect of intramolecular H-bonding on the population of nitrogen invertomers and inversion process
作者:Shaikh A. Ali、Muhammad Z.N. Iman、Mohamed I.M. Wazeer、Mohammed B. Fettouhi
DOI:10.1016/j.saa.2007.07.032
日期:2008.8
diasteromer almost exclusively as a single invertomer having trans disposition of the substituents at N(2) and C(5), while the (betaR,5R) diasteromer remained as a mixture of two interconverting invertomers in deuterated chloroform. The effect of H-bonding - intramolecular in CDCl(3) and intermolecular in CD(3)OD - on the population ratio of the invertomers and nitrogen inversion process has been investigated
通过不对称的硝酮环加成反应制备了一系列的(betaR,5R)-和(betaR,5S)-2,5-二取代的异恶唑烷:5-(取代基)-β-苯基-2-异恶唑烷乙醇,并记录了其NMR光谱在很宽的温度范围内。低温下的光谱表明(βR,5S)非对映体的存在几乎全部是单个取代基,在N(2)和C(5)处具有取代基的转位,而(βR,5R)非对映体仍保留为氘代氯仿中两种相互转化的反相异构体的混合物 研究了H键(CDCl(3)中的分子内和CD(3)OD中的分子间)对不饱和聚合物的种群比例和氮转化过程的影响。使用完整的线形分析来确定氮转化障碍,并讨论了它们对溶剂的依赖性。由于空间因素,发现反式-反向异构体比其顺式-反向异构体更稳定。