荧光染料的合成。九。新的4-羟基香豆素,4-羟基-2-喹诺酮类,2 H,5 H-吡喃并[3,2- c ]苯并吡喃-2,5-二酮和2 H,5 H-吡喃并[3,2- c ]喹啉-2,5-二酮†
摘要:
由适当的酚或苯胺合成了7位取代的4-羟基香豆素(2a-e)和4-羟基-2-喹诺酮(2f-i),并使用三乙氧基甲烷和苯胺将其转化为烯胺3。3与腈4a-h的缩合反应生成2 H,5 H-吡喃并[3,2- c ]苯并吡喃-2,5-二酮(5a-r)或2 H,5 H-吡喃并[3,2- c ]喹啉-2,5-二酮(5s-x),显示出自发的和受激的荧光,最大值介于418和549 nm之间。7a,b(由2d,e和3-氧代丁酸乙酯合成)的荧光光谱证明了5中的吸电子3取代基的显着影响,与化合物21-r相比,其最大值急剧转变为蓝色。。
CO2 as a C1-building block for the catalytic methylation of amines
作者:Olivier Jacquet、Xavier Frogneux、Christophe Das Neves Gomes、Thibault Cantat
DOI:10.1039/c3sc22240c
日期:——
A novel catalytic reaction has been designed to utilize, for the first time, CO2 as a C1 feedstock in the synthesis of N-methylamines. Simple zinc catalysts, based on commercially available zinc salts and ligands, prove highly efficient in promoting both a 6 electron reduction of carbon dioxide and the formation of a C–N bond, using hydrosilanes and amines.
A substituent- and temperature-controllable NHC-derived zwitterionic catalyst enables CO<sub>2</sub> upgrading for high-efficiency construction of formamides and benzimidazoles
作者:Zhaozhuo Yu、Zhengyi Li、Lilong Zhang、Kaixun Zhu、Hongguo Wu、Hu Li、Song Yang
DOI:10.1039/d1gc01897c
日期:——
zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%–98%). The electronic effect of the introduced substituent
近年来,将温室气体CO 2化学催化升级为有价值的化学品和生物燃料引起了广泛关注。在已报道的方法中,CO 2与胺的N-甲酰化由于其在构建含N 线性和环状骨架方面的多功能性而具有重要意义。这里,稳定的N-杂环卡宾-羧基加合物(NHC-CO 2)中制备的轻便和可作为用于高效CO可回收两性离子催化剂2还原升级经由任一Ñ -formylation或另外的耦合用温和的条件下环化(25 °C, 1 atm CO 2) 使用氢硅烷作为氢源。超过 30 种不同的烷基和芳香胺可以转化为相应的甲酰胺或苯并咪唑,产率显着(74%–98%)。发现引入的取代基对NHC-CO 2的电子效应明显影响两性离子催化剂的热稳定性和亲核性,这与其催化活性直接相关。此外,NHC-CO 2可以通过在特定温度下原位脱羧来提供CO 2,这取决于引入的取代基类型。实验和计算研究表明,NHC-CO 2上的羧基物质不仅是亲核中心,而且还是在氢化硅烷化过程中快速捕获或替代环境
Highly selective hydrogenation of amides catalysed by a molybdenum pincer complex: scope and mechanism
of molybdenum pincer complexes has been shown for the first time to be active in the catalytic hydrogenation of amides. Among the tested catalysts, Mo-1a proved to be particularly well suited for the selective C–N hydrogenolysis of N-methylated formanilides. Notably, high chemoselectivity was observed in the presence of certain reducible groups including even other amides. The general catalytic performance
Palladium-Catalyzed Intermolecular Coupling of Aryl Halides and Amides
作者:Jingjun Yin、Stephen L. Buchwald
DOI:10.1021/ol005654r
日期:2000.4.1
[formula: see text] The first general intermolecular C-N bond-forming reactions betweenarylhalides and amides were realized using a palladium catalyst with Xantphos as the ligand. Aryl triflates, carbamates, and sulfonamides are also viable substrates for the amidations, which proceed at 45-110 degrees C with 1-4 mol% of Pd catalyst in 66-99% yields and exhibit good functional group compatibility