Synthesis of stable tetrahedral intermediates (hemiaminals) and kinetics of their conversion to thiazol-2-imines
作者:Sule Erol Gunal、Gulben Sabuncu Gurses、Safiye Sag Erdem、Ilknur Dogan
DOI:10.1016/j.tet.2016.03.003
日期:2016.4
Tetrahedral intermediates (hemiaminals) during thiazol-2-imine formation reactions have been isolated as stable compounds from the LiAlH4 reduction of the corresponding 2-arylimino-3-aryl-thiazolidine-4-ones and identified by 1H NMR spectroscopy. In solution, the hemiaminals have been found to slowly convert to the corresponding thiazol-2-imines over time. The first order rate constants for the conversion
已经从相应的2-芳基氨基-3-芳基-噻唑烷-4-酮的LiAlH 4还原中分离出作为稳定化合物的噻唑-2-亚胺形成反应中的四面体中间体(半缩醛),并通过1 H NMR光谱法鉴定。在溶液中,已发现随着时间的流逝,半胱氨酸缓慢转化为相应的噻唑-2-亚胺。转换过程的一阶速率常数由与时间有关的1确定1 H NMR光谱分析。发现的半胱氨酸半衰期为2.5-160天。血友病菌易于形成的主要原因是酰胺氮N3的亚胺共轭,这有望通过使酰胺氮上的孤对电子向亚胺侧移动来提高酰胺羰基的亲电性。Hemiaminals的稳定性归因于Hemiaminal氮的am共轭和O的分子内H键相互作用通过计算研究证实了-甲氧基苯基衍生物。通过DFT / M06-2X / 6-31 + G(d,p)方法研究了反应机理。计算和实验数据与酸催化除水机理有关,该机理用于将半胱氨酸转化为噻唑-2-亚胺。用DFT / M06-2X / 6-31 +