作者:Joel M. Smith、Tian Qin、Rohan R. Merchant、Jacob T. Edwards、Lara R. Malins、Zhiqing Liu、Guanda Che、Zichao Shen、Scott A. Shaw、Martin D. Eastgate、Phil S. Baran
DOI:10.1002/anie.201705107
日期:2017.9.18
The development of a new decarboxylative cross‐coupling method that affords terminal and substituted alkynes from various carboxylic acids is described using both nickel‐ and iron‐based catalysts. The use of N‐hydroxytetrachlorophthalimide (TCNHPI) esters is crucial to the success of the transformation, and the reaction is amenable to in situ carboxylic acid activation. Additionally, an inexpensive
Mechanistic Insights into the One-Pot Synthesis of Propargylamines from Terminal Alkynes and Amines in Chlorinated Solvents Catalyzed by Gold Compounds and Nanoparticles
作者:David Aguilar、Maria Contel、Esteban P. Urriolabeitia
DOI:10.1002/chem.201000587
日期:——
Propargylamines can be obtained from secondary amines and terminal alkynes in chlorinated solvents by a three‐ and two‐component synthesiscatalyzed by gold compounds and nanoparticles (Au‐NP) under mild conditions. The use of dichloromethane allows for the activation of two CCl bonds and a clean transfer of the methylene fragment to the final product. The scope of the reaction as well as the influence
Synthesis of 13C4-labelled oxidized metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene
作者:Anhui Wu、Daiwang Xu、Ding Lu、Trevor M. Penning、Ian A. Blair、Ronald G. Harvey
DOI:10.1016/j.tet.2012.05.130
日期:2012.9
sensitive stable isotope dilution LC/MS method for analysis of BaP metabolites. We now report efficient syntheses of 13C4-BaP and the complete set of its 13C4-labelled oxidized metabolites needed as internal standards They include the metabolites not involved in carcinogenesis (Group A) and the metabolites implicated in initiation of cancer (Group B). The synthetic approach is novel, entailing use of Pd-catalyzed
多环芳烃 (PAH),例如苯并 [ a ] 芘 (B a P),是普遍存在的环境污染物,与导致肺癌有关。B a P 是烟草烟雾的一种成分,通过酶促转化为与 DNA 相互作用的活性形式。我们之前报道了一种用于分析 B a P 代谢物的灵敏的稳定同位素稀释 LC/MS 方法的开发。我们现在报告了13 C 4 -B a P 的有效合成及其完整的13 C 4标记氧化代谢物,需要作为内标。它们包括不参与致癌作用的代谢物(A 组))和与癌症发生有关的代谢物(B组)。该合成方法是新颖的,需要使用 Pd 催化的 Suzuki、Sonogashira 和 Hartwig 交叉偶联反应与 PtCl 2催化的炔属化合物环化反应相结合。这种合成方法需要更少的步骤,使用更温和的条件,并且产物分离比传统的 PAH 合成方法更简单。13 C 4 -B a P 和13 C 4 -B a P-8-ol的合成各只需要四步,并且13
Accessing Long-Lived Disconnected Spin-<sup>1</sup>/<sub>2</sub> Eigenstates through Spins > <sup>1</sup>/<sub>2</sub>
作者:Kevin Claytor、Thomas Theis、Yesu Feng、Jin Yu、David Gooden、Warren S. Warren
DOI:10.1021/ja505792j
日期:2014.10.29
Pairs of chemicallyequivalent (or nearly equivalent) spin-1/2 nuclei have been shown to create disconnected eigenstates that are very long-lived compared with the lifetime of pure magnetization (T1). Here the classes of molecules known to have accessible long-lived states are extended to include those with chemicallyequivalent spin-1/2 nuclei accessed by coupling to nuclei with spin > 1/2, in this