A General Strategy for Site-Selective Incorporation of Deuterium and Tritium into Pyridines, Diazines, and Pharmaceuticals
作者:J. Luke Koniarczyk、David Hesk、Alix Overgard、Ian W. Davies、Andrew McNally
DOI:10.1021/jacs.7b11710
日期:2018.2.14
molecules are valuable for medicinal chemistry. The prevalence of pyridines and diazines in pharmaceuticals means that new ways to label these heterocycles will present opportunities in drug design and facilitate absorption, distribution, metabolism, and excretion (ADME) studies. A broadly applicable protocol is presented wherein pyridines, diazines, and pharmaceuticals are converted into heterocyclic phosphonium
Remote site-selective C–H activation directed by a catalytic bifunctional template
作者:Zhipeng Zhang、Keita Tanaka、Jin-Quan Yu
DOI:10.1038/nature21418
日期:2017.3
In chemical syntheses, the activation of carbon–hydrogen (C–H) bonds converts them directly into carbon–carbon or carbon–heteroatom bonds without requiring any prior functionalization. C–Hactivation can thus substantially reduce the number of steps involved in a synthesis. A single specific C–H bond in a substrate can be activated by using a ‘directing’ (usually a functional) group to obtain the desired
Nitro group reduction and Suzuki reaction catalysed by palladium supported on magnetic nanoparticles modified with carbon quantum dots generated from glycerol and urea
stabilization of palladium species and the prepared catalyst, Pd@CQD@Fe3O4, was characterized using various techniques. This magnetic supported palladium was applied as an efficient catalyst for the reduction of aromatic nitro compounds to primary amines at roomtemperature using very low palladium loading (0.008 mol%) and also for the Suzuki–Miyaura cross‐coupling reaction of aryl halides as well as challenging
甘油和尿素用作绿色廉价的碳量子点(CQD)来源,用于修饰Fe 3 O 4纳米颗粒(NPs)。所获得的CQD @ Fe 3 O 4 NP用于稳定钯物质和制备的催化剂Pd @ CQD @ Fe 3 O 4。,使用各种技术进行了表征。这种磁性负载的钯被用作有效的催化剂,用于在室温下使用极低的钯负载量(0.008 mol%)将芳族硝基化合物还原为伯胺,以及用于芳烃卤化物的Suzuki-Miyaura交叉偶联反应以及具有挑战性的杂芳基溴化物和芳基重氮盐与芳基硼酸和苯基三氟硼酸钾。回收了这种可磁循环的催化剂,并将其连续7次重复使用,以将4-硝基甲苯还原为p甲苯胺和4-碘苯甲醚与苯基硼酸的反应连续十次,活性降低很小。使用透射电子显微镜,振动样品磁力分析和X射线光电子能谱对在铃木反应中重复使用的催化剂进行了表征。通过热过滤和中毒试验等实验,已经证明,根据活性钯物质的释放-返回途径,真正的催化剂可以在均相条件下工作。
Ligand-free Pd/C-catalyzed Suzuki–Miyaura coupling reaction for the synthesis of heterobiaryl derivatives
We have developed a mild and efficient protocol for the ligand-free and heterogeneous Pd/C-catalyzed hetero SuzukiâMiyaura coupling reaction that allows for the synthesis of both heteroarylâaryl and heteroarylâheteroaryl derivatives in good to excellent yields.
Phosphonium Salts as Pseudohalides: Regioselective Nickel‐Catalyzed Cross‐Coupling of Complex Pyridines and Diazines
作者:Xuan Zhang、Andrew McNally
DOI:10.1002/anie.201704948
日期:2017.8.7
traditional cross‐coupling methods. An alternative approach is presented where pyridines and diazines are converted into heteroaryl phosphonium salts and coupled with aryl boronic acids. Nickel catalysts are unique for selective heteroaryl transfer, and the reaction has a broad substrate scope that includes complex pharmaceuticals. Phosphonium ions also display orthogonal reactivity in cross‐couplings compared