Accessing Polysubstituted Quinazolines via Nickel Catalyzed Acceptorless Dehydrogenative Coupling
作者:Seuli Parua、Rina Sikari、Suman Sinha、Gargi Chakraborty、Rakesh Mondal、Nanda D. Paul
DOI:10.1021/acs.joc.8b01479
日期:2018.9.21
easy to prepare nickel catalysts, containing tetraaza macrocyclic ligands (tetramethyltetraaza[14]annulene (MeTAA) or 6,15-dimethyl-8,17-diphenyltetraaza[14]annulene (MePhTAA)) are reported. A wide variety of substituted quinazolines were synthesized in moderate to high yields starting from cheap and easily available starting precursors. A few control reactions were performed to understand the mechanism
Efficient synthesis of quinazolines by the iron-catalyzed acceptorless dehydrogenative coupling of (2-aminophenyl)methanols and benzamides
作者:Shi-Qi Zhang、Yao Cui、Bin Guo、David J. Young、Ze Xu、Hong-Xi Li
DOI:10.1016/j.tet.2020.131825
日期:2021.1
The acceptorless dehydrogenation coupling (ADC) of (2-aminophenyl)methanols with benzamides was achieved with catalytic FeCl2·4H2O in an efficient synthesis of quinazolines. This simple catalytic system is atom-economical, environmentally benign and suited to a variety of substrates.
atom-efficient synthesis of 2-substituted quinazolines is developed by a CsOH-mediated direct aerobic oxidative reaction of the readily available and stable 2-aminoarylmethanols and nitriles. Effectively working as the promoter in the alcohol oxidation, nitrile hydration, and cyclocondensation steps, CsOH is the best base for the reaction. A similar method can also be extended to the synthesis of substituted
range of quinazoline derivatives was fabricated with excellent yields using 0.5 mol% Pd(II) catalyst loading. The catalyticcoupling process was performed under aerobic conditions and water is the only by-product. With data from the control experiments, a plausible mechanism for the dehydrogenative coupling reaction was proposed via a cyclic aminal intermediate through the oxidation of alcohol to aldehyde
报道了一种新的钯 ( II ) N、N、O型配合物促进喹唑啉单锅级联合成,通过容易获得的醇和 2-氨基苄胺的脱氢偶联。一组独特的 Pd( II ) 配合物 ( 1-2 ) 被合成并通过分析和光谱技术表征。单晶 X 射线衍射研究证实了钯离子周围的方形平面几何形状。使用 0.5 mol% Pd( II) 催化剂负载。催化偶联过程在有氧条件下进行,水是唯一的副产品。与来自对照实验的数据,脱氢偶联反应的可行的机制,提出了通过环状缩醛胺中间体通过醇氧化成醛。克级合成证明了所提出协议的有效性。