电喷雾萃取电离质谱监测Doebner-Von Miller反应

Monitoring the Catalytic Process of Doebner-Von Miller Reaction by EESI-MS

分别以碘和对甲苯磺酸为催化剂,用电喷雾萃取电离质谱(EESI-MS)在线监测了正丁醛与苯胺、对甲苯胺、对甲氧基苯胺等3种芳香胺间的Doebner-Von Miller反应。通过捕捉到的产物、中间体及反应物的准分子离子信号,推测了反应机理。苯胺首先与醛进行亲核加成消除反应生成亚胺;亚胺再与另一分子醛进行迈克尔加成反应;最后经自身环化-缩合脱水-脱氢芳构化,得喹啉类化合物。比较碘和对甲苯磺酸的催化效果时发现,以对甲苯磺酸为催化剂时反应达到平衡所需时间较短。

The iodine or p-toluenesulfonic acid catalyzed the reaction between three aromatic amines and n-butyraldehyde was monitored online by EESI-MS(extractive electrospray ionization tandem mass spectrometry),and the quasi molecular ion signals of reactant,intermediate and product were captured.Then the presumed mechanism was deduced:aniline and aldehyde were eliminated by addition reaction to form an imine,and the intermediate was formed from imine and another aldehyde by Michael addition reaction,and then the quinoline derivative was produced by the intermediate's self-cyclization dehydration and dehydrogenation aromatization.Comparing the catalytic effects of iodine and p-toluene sulfonic acid,the reaction time was shorter when p-toluene sulfonic acid was used as catalyst.