Highly Selective C−H Functionalization/Halogenation of Acetanilide
摘要:
Highly regioselective C-H functionalization/halogenation of acetanilides to produce ortho-haloacetanilides was catalyzed by Pd(OAc)2 and Cu(OAc) 2 with CuX2 as the halogen source.
A Versatile, Practical, and Inexpensive Reagent, Pyridine-3-carboxylic Anhydride (3-PCA), for Condensation Reactions
作者:Setsuo Funasaka、Teruaki Mukaiyama
DOI:10.1246/bcsj.81.148
日期:2008.1.15
A highly useful method for the preparation of carboxylic esters and carboxamides from various carboxylic acids was established by using a novel condensing reagent, pyridine-3-carboxylic anhydride (3-PCA), in the presence of 4-(dimethylamino)pyridine as an activator. The reactions of various carboxylic acids with nucleophiles, such as alcohols or amines, afforded the corresponding carboxylic acids or carboxamides in good to high yields under mild conditions by using simple experimental procedure. In addition, it was confirmed that this protocol was applicable to a gram-scale synthesis and the by-products, including pyridine-3-carboxylic acid and pyridine-3-carboxylate (or pyridine-3-carboxamide) produced in situ, were easily removed by using a simple aqueous workup.
Water Solvent Method for Esterification and Amide Formation between Acid Chlorides and Alcohols Promoted by Combined Catalytic Amines: Synergy betweenN-Methylimidazole andN,N,N′,N′-Tetramethylethylenediamine (TMEDA)
An efficient method for esterificationbetweenacidchlorides and alcohols in water as solvent has been developed by combining the catalyticamines, N-methylimidazole and N,N,N′,N′-tetramethylethylenediamine (TMEDA). The present Schotten–Baumann-type reaction was performed by maintaining the pH at around 11.5 using a pH controller to prevent the decomposition of acidchlorides and/or esters and to
通过将催化胺,N-甲基咪唑和N,N,N',N'-四甲基乙二胺(TMEDA)结合在一起,已开发出一种有效的方法,用于在水中作为溶剂在酰氯和醇之间进行酯化。通过使用pH调节剂将pH值保持在11.5左右,可以防止酸氯和/或酯类的分解并促进缩合,从而完成当前的Schotten-Baumann型反应。催化剂的选择(0.1当量)至关重要:N-甲基咪唑和TMEDA的组合使用具有显着的协同作用。催化胺具有两个不同的作用:(i)N-甲基咪唑与酰氯形成高反应性的铵中间体,并且(ii)TMEDA充当有效的HCl粘合剂。仔细的1 H NMR监测研究合理地支持了这些中间体的生产。在酰氯和伯胺或仲胺之间也实现了相关的酰胺形成,伯胺或仲胺包括较少的亲核或水溶性胺,例如2-(或4-)氯苯胺,Weinreb N-甲氧基胺和2,2-二甲氧基乙胺。
Mild, powerful, and robust methods for esterification, amide formation, and thioesterification between acid chlorides and alcohols, amines, thiols, respectively
practical methods for esterification, amideformation, and thioesterification betweenacidchlorides and alcohols, amines, thiols, respectively. The present mild and robust reaction was performed by two separate methods both by combining cheap and readily available amines, N-methylimidazole, and N,N,N′,N′-tetramethylethylenediamine (TMEDA). Method A uses catalytic N-methylimidazole and TMEDA with an
我们开发了两种有效的实用方法,分别用于酰氯与醇,胺,硫醇之间的酯化,酰胺形成和硫酯化。本发明的温和而稳固的反应是通过两种单独的方法进行的,两者都是通过组合廉价且容易获得的胺,N-甲基咪唑和N,N,N ',N'-四甲基乙二胺(TMEDA)。方法A使用等摩尔量的K 2 CO 3催化N-甲基咪唑和TMEDA ,而方法B使用等摩尔量的N-甲基咪唑和TMEDA。其主要特征如下。(i)就反应性而言,方法B在酯化和硫代酯化方面优于方法A,而经济高效的方法A在酰胺形成方面优于方法B。(ii)酰氯与较少亲核和立体拥挤的胺(如2,6-二氯苯胺)之间的酰胺形成过程顺利进行。(iii)该方案适用于成功合成两种农用化学品,溴丁酸酯和杀虫剂。
Intermediate formation enabled regioselective access to amide in the Pd-catalyzed reductive aminocarbonylation of olefin with nitroarene
作者:Li Yang、Lijun Shi、Chungu Xia、Fuwei Li
DOI:10.1016/s1872-2067(20)63561-6
日期:2020.7
reductive aminocarbonylation of olefins with nitroarenes was developed using carbon monoxide (CO) as both reductant and carbonyl source, which enables facile access to amides with excellent regioselectivity and broad substrate scope. It is found that the counter anions of the Pd catalyst precursors significantly affect the reaction chemoselectivity and amide regioselectivity. Branched amides were mainly
摘要 以一氧化碳 (CO) 作为还原剂和羰基源,开发了一种钯催化烯烃与硝基芳烃还原氨基羰基化的有效途径,该途径可以轻松获得具有优异区域选择性和广泛底物范围的酰胺。发现Pd催化剂前体的抗衡阴离子显着影响反应化学选择性和酰胺区域选择性。支链酰胺主要以K2PdCl4为金属催化剂得到,膦配体对区域选择性没有影响,但影响催化反应活性。然而,当使用 Pd(CH3CN)4(OTf)2 时,膦配体对氨基羰基化区域选择性有显着影响;单齿膦倾向于形成支链酰胺,而双齿膦主要形成线性酰胺。从硝基芳烃还原的所有可能的 N 物种的捕获实验、初级动力学研究和控制反应表明,支链和线性酰胺的催化合成分别产生了氮烯(进一步转化为烯酰胺)和苯胺,这与之前的配体控制的区域选择性不同通过烯烃与胺的氨基羰基化合成酰胺。此外,所提出的合成路线可用于在温和条件下合成克级丙腈。与以前通过烯烃与胺的氨基羰基化合成酰胺的配体控制的区域选择性不
Migration of the Hydroxyl Group of N-Hydroxy-N-phenylamides to the Phenyl Group with Tertiary Phosphines and Tetrachloromethane. A Novel Transhydroxylation Reaction
作者:Yasuo Kikugawa、Kimiyo Mitsui
DOI:10.1246/cl.1993.1369
日期:1993.8
N-hydroxy-N-phenylamides rearranges mainly to the ortho position of the N-phenyl ring by the system (n-Bu)3P-CCl4-CH3CN; use of less than a stoichiometric amount of (n-Bu)3P is effective for this reaction.