基于苯并硫氮杂卓的亚胺、烯胺在质子溶剂中的稳定性及其互变异构  

The stability and tautomerism of imines and enamines based on benzothiazepines in protic solvents

作　　者：王丽娜[1] 安志敏[1] 李媛[1] 

机构地区：[1]河北师范大学化学与材料科学学院,石家庄050024

出　　处：《中国科学：化学》2014年第12期1976-1985,共10页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(20972040);河北师范大学研究生科研基金资助

摘　　要：用核磁共振法研究了亚胺型杂卓1和烯胺型杂卓2在不同质子溶剂—甲醇、乙醇、叔丁醇、乙酸及CF3CO2D的DMSO-d6溶液中的稳定性及互变异构.结果表明,烯胺型杂卓2在上述溶剂中稳定,亚胺型杂卓1在酸性较弱的质子溶剂中（乙醇、叔丁醇）及较低的温度下（≤30℃）基本稳定,在酸性较强的质子溶剂中（甲醇、乙酸、CF3CO2D的DMSO-d6溶液）向烯胺转化,而且随着溶剂酸性的增强、温度的升高以及反应物与溶剂接触时间的延长,亚胺向烯胺的转化进一步加强.本文还以1a和1b为例,研究了在乙酸溶液中亚胺型杂卓向烯胺型杂卓转化的热力学和动力学特征.研究表明,在283-333 K范围内,该转化的焓变（△H）和熵变（△S）均大于零,吉布斯自由能变（△G）小于零,因此其是吸热、自发及熵增加的过程,该过程可用二级动力学方程来描述,质子对亚胺向烯胺的转化起催化作用.The stability and tautomerism of imines（1a–1c） and enamines（2a–2c） in various protic solvents（methyl alcohol, ethyl alcohol, tert-butyl alcohol, acetic acid and CF3CO2 D DMSO-d6 solution） were investigated via 1H NMR spectral data. It was found that enamines（2a–2c） were stable in above solvents and imines（1a–1c） were stable at lower temperature（≤30 °C） in weak acid solvents（ethyl alcohol, tert-butyl alcohol）, but imines converted into enamines in methyl alcohol, acetic acid and CF3CO2 D DMSO-d6 solution. It was also found that along with the increase of acidity in solution, the extension of time and the temperature rising, more and more imines converse to enamines. The kinetic and thermodynamic characteristics of the conversion of imines to enamines in acetic acid were studied by taking 1a and 1b as examples. The results showed that transformation from imines（1a and 1b） to enamines（2a and 2b） is endothermic and thermodynamically feasible in the temperature range of 283–333 K（△H 〉0, △G〈 0）, and the values of entropy change are positive（△S 〉0）. The transformation follows the second-order kinetic equation at above temperatures and the proton in solution catalyzes the conversion of imines to enamines.

关 键 词：1 5-苯并硫氮杂卓 亚胺 烯胺 互变异构 热力学 动力学 

分 类 号：O621.2[理学—有机化学]