Reactions of Grignard Reagents with Bis- or Mono-Phosphonium lons in Situ Generated from Bu3P and Dicarboxylic Acid Dichlorides or .OMEGA.-Ethoxycarbonyl Alkanoyl Chlorides as a Novel Method to Obtain Diketones and Ketoesters.
mixture of BusP and the Grignard reagent (2.0 eq each) was added to the dichloride solution at the same temperature, a better result was obtained. The latter method not with PhMgBr but with n-BuMgCl or MeMgBr was shown to be useful for preparation of symmetrical alkanediones and keto alkanoates from various 5 (n=2-6) and 13 (n=2 or 3), respectively. For synthesis of alpha-diketones or alpha-ketoesters
Synthesis of 1,4-Diketones by Reaction of Bicyclic Lactams Derived from 4-Oxoalkanoic Acids with Organolithium Compounds
作者:Christine Wedler、Hans Schick
DOI:10.1055/s-1992-26159
日期:——
Bicyclic lactams obtained from ethyl 4-oxoalkanoates and 2-aminoethanol add saturated and unsaturated aliphatic lithium compounds forming the corresponding 1,4-diketones in 41-61% yield after acidic hydrolysis.
methods that address the selective formation of (Z)-olefins. In such cases, specific catalysts (e. g., cross-metathesis)3 or modified anion stabilizing groups (e. g., Still-Gennari modification of Horner-Wadsworth-Emmonsolefination)4 are utilized. The Peterson olefination,2g, 2h on the other hand, allows for the stereoselective formation of either (E) or (Z)-olefins from the same starting material by a
介绍 碳-碳键形成反应是有机合成化学中的关键连接反应。其中,不饱和键(特别是烯烃)的立体选择性形成具有重要意义,因为它们参与天然产物、生物活性化合物和材料的合成。目前,实现立体选择性连接烯化的两种常用方法是烯烃交叉复分解1和阴离子稳定试剂与醛或酮的偶联2(图 1)。这些方法通常在温和的反应条件下进行,对官能团表现出良好的耐受性,并且主要产生( E )-构型的烯烃。然而,解决( Z )-烯烃的选择性形成的方法有限。在这种情况下,使用特定的催化剂(例如交叉复分解)3或改性阴离子稳定基团(例如Horner-Wadsworth-Emmons烯化的Still-Gennari改性)4 。另一方面,Peterson 烯化(2g,2h)允许通过反应后处理(酸性与碱性)的简单改变,从相同的起始材料立体选择性地形成( E)或(Z )-烯烃。 5然而,即使在这种情况下,原位生成的加合物 (顺/反)的立体选择性也反映在烯化反应的最终立体化学结果中。
METHOD FOR PRODUCING PURIFIED POLYTETRAFLUOROETHYLENE AQUEOUS DISPERSION LIQUID, METHOD FOR PRODUCING MODIFIED POLYTETRAFLUOROETHYLENE POWDER, METHOD FOR PRODUCING POLYTETRAFLUOROETHYLENE MOLDED BODY, AND COMPOSITION
申请人:Daikin Industries, Ltd.
公开号:EP3666802A1
公开(公告)日:2020-06-17
An object of the present invention is to obtain an aqueous dispersion of polytetrafluoroethylene in which compounds containing fluorine are removed or reduced. The present invention is a method for producing an aqueous dispersion of purified polytetrafluoroethylene, the method including: removing or reducing a compound represented by Formula (1) or (2) below from an aqueous dispersion of polytetrafluoroethylene obtained using a hydrocarbon surfactant:
Formula (1): (H-(CF2)m-COO)pM1; or
Formula (2): (H-(CF2)n-SO3)qM2.
Provided is a method for producing polytetrafluoroethylene comprising polymerizing tetrafluoroethylene in an aqueous medium in the presence of a nucleating agent and a hydrocarbon anionic surfactant to obtain polytetrafluoroethylene, wherein a total amount of the nucleating agent and the hydrocarbon anionic surfactant at the initiation of polymerization is more than 50 ppm based on the aqueous medium.