Ionic Liquid as Reagent. A Green Procedure for the Regioselective Conversion of Epoxides to Vicinal-Halohydrins Using [AcMIm]X under Catalyst- and Solvent-Free Conditions
摘要:
A variety of structurally diverse epoxides undergo facile cleavages by ionic liquid, [AcMIm]X without any catalyst and solvent to produce the corresponding vicinal halohydrins in high yields. The cleavages are considerably fast and highly regioselective.
Method for producing polydienes and polydiene copolymers with reduced cold flow
申请人:BRIDGESTONE CORPORATION
公开号:US10301397B2
公开(公告)日:2019-05-28
A method for preparing a coupled polymer, the method comprising the steps of (i) polymerizing monomers to form a reactive polymer, and (ii) reacting the reactive polymer with a glycidic ester.
The catalytic efficiency of InCl3, Yb(OTf)(3), and Sc(OTf)(3) in the azidolysis of alpha,beta -epoxycarboxylic acids has been studied in water and in organic solvents, for comparison using NaN3 and Me3SiN3 as the source of the azido group. In water, the catalytic effectiveness of these metal salts strongly depends on the pH of the aqueous medium and on the type of Lewis acid catalyst. In water their catalytic activity is mostly due to the corresponding aqua ion species, the concentration of which becomes significant when the pH of the aqueous medium is below the corresponding pK(1,1) hydrolysis constant. The process is more efficient in water than in organic solvents. At pH 4.0, InCl3 is a far better catalyst than Yb(OTf)(3) or Sc(OTf)(3) and allows the highly regio- and diasteroselective preparation of beta -azido-alpha -hydroxycarboxylic acids, which can be isolated in pure form in very high yields.
KRAUS G. A.; FRAZIER K., J. ORG. CHEM., 1980, 45, NO 13, 2579-2581