制备了一系列的单取代的嘧啶鎓和吡嗪鎓三氟甲磺酸酯和3,5-二取代的吡啶鎓三氟甲磺酸酯,并使用硫氧化作为模型反应,对过氧化氢的简单氧化催化剂进行了测试。它们的催化效率在很大程度上取决于取代基的类型,并且对于具有吸电子基团的衍生物而言是显着的,其反应性与黄酮盐相当,后者是氧合作用的主要有机催化剂。由于它们的高稳定性和良好的可及性,4-(三氟甲基)嘧啶鎓和3,5-二硝基吡啶鎓三氟甲磺酸盐是选择的催化剂,并显示出催化脂肪族和芳香族硫化物氧化为亚砜的作用,定量转化率高,制备产率高,并且具有优异的性能。化学选择性。K R +值(p K R + <5)和较小的负还原电位(E red > -0.5 V)。在催化氧化过程中原位形成的过氧化氢加合物充当底物氧化剂。通过在B3LYP / 6-311 ++ g(d,p)水平上的计算获得的从这些杂环氢过氧化物到硫代苯甲醚的转移的吉布斯自由能表明,它们是比烷基氢过氧化
prepared and tested as simple catalysts of oxidations with hydrogen peroxide, using sulfoxidation as a model reaction. Their catalyticefficiency strongly depends on the type of substituent and is remarkable for derivatives with an electron-withdrawing group, showing reactivity comparable to that of flaviniumsalts which are the prominent organocatalysts for oxygenations. Because of their high stability
制备了一系列的单取代的嘧啶鎓和吡嗪鎓三氟甲磺酸酯和3,5-二取代的吡啶鎓三氟甲磺酸酯,并使用硫氧化作为模型反应,对过氧化氢的简单氧化催化剂进行了测试。它们的催化效率在很大程度上取决于取代基的类型,并且对于具有吸电子基团的衍生物而言是显着的,其反应性与黄酮盐相当,后者是氧合作用的主要有机催化剂。由于它们的高稳定性和良好的可及性,4-(三氟甲基)嘧啶鎓和3,5-二硝基吡啶鎓三氟甲磺酸盐是选择的催化剂,并显示出催化脂肪族和芳香族硫化物氧化为亚砜的作用,定量转化率高,制备产率高,并且具有优异的性能。化学选择性。K R +值(p K R + <5)和较小的负还原电位(E red > -0.5 V)。在催化氧化过程中原位形成的过氧化氢加合物充当底物氧化剂。通过在B3LYP / 6-311 ++ g(d,p)水平上的计算获得的从这些杂环氢过氧化物到硫代苯甲醚的转移的吉布斯自由能表明,它们是比烷基氢过氧化
Ionic liquids and their use in extraction processes
申请人:BP p.l.c.
公开号:EP1854786A1
公开(公告)日:2007-11-14
There is provided a process for the extraction of at least one aromatic compound from a mixture with at least one aliphatic hydrocarbon, which process comprises contacting said mixture with a salt that is in a liquid state at a temperature below 150°C, said salt having a cation which comprises an aromatic nitrogen-containing heterocyclic ring system, in which a nitrogen atom forming part of said ring system is quaternised and in which said ring system is substituted by at least one electron-withdrawing substituent. Some of said salts are novel.
A predictive model for additions to <i>N</i>-alkyl pyridiniums
作者:Brian J. Knight、Zachary A. Tolchin、Joel M. Smith
DOI:10.1039/d1cc00056j
日期:——
Disclosed in this communication is a thorough study on the dearomative addition of organomagnesium nucleophiles to N-alkyl pyridinium electrophiles. The regiochemical outcomes have observable and predictable trends associated with the substituent patterns on the pyridinium electrophile. Often, the substituent effects can be either additive, giving high selectivities, or ablative, giving competing outcomes
Rhodium-Catalyzed Enantioselective Addition of Heteroarenium Salts Enabled by Nucleophilic Cyclization of 2-Alkynylanilines
作者:Yaling Huang、Zisong Qi、Xingwei Li
DOI:10.1021/acs.orglett.3c03300
日期:2023.12.1
Transition-metal-catalyzed cyclative coupling of 2-alkynylanilines provides a feasible routine for accessing functionalized indoles. Herein, a rhodium-catalyzed highly enantioselective addition of heteroarenium salts is presented, which is enabled by the nucleophilic cyclization of 2-alkynylanilines. It offers feasible protocols to access enantioenriched functionalized indoles tethered to 1,2-dihydropyridine