462-26-0Relevant articles and documents
1- and 2-Fluoroalkyl Carboxylates
Limat, Dominique,Guggisberg, Yves,Schlosser, Manfred
, p. 849 - 854 (2007/10/02)
The 2-fluoroalkyl esters (1-4) of carboxylic acids are readily accessible by the base-catalyzed acylation of fluorohydrines.A two-step procedure is required to prepare the 1-fluoroalkyl esters (10-14, 16): conversion of alk-1-enyl carboxylates ("ene esters") into the 2-bromo-1-fluoroalkyl esters 5-9, 15, 17-19 by simultaneous treatment with N-bromosuccinimide and hydrogen fluoride followed by the reductive replacement of bromine by tributyltin hydride.Alka-1,3-dienyl carboxylates ("diene esters") undergo 1,4-addition of bromine and fluorine.The resulting 4-bromo-1-fluoroalk-2-enyl carboxylates 20-25 undergo a substitution reaction with sodium benzenesulfinate to afford the sulfones 26-28 or oxidation with dimethyl sulfoxide to yield the 4-oxo derivatives 29-30. - Key Words: Organofluorine compounds / 1-Fluoroalkyl esters / 2-Fluoroalkyl esters / Ene esters / Diene esters
Effects of Polar β Substituents in the Gas-Phase Pyrolysis of Ethyl Acetate Esters
Chuchani, Gabriel,Martin, Ignacio,Hernandez, Jose A. A.,Rotinov, Alexandra,Fraile, German,Bigley, David B.
, p. 944 - 948 (2007/10/02)
The rates of the gas phase pyrolysis of six β-substituted ethyl acetates were studied in a static system over the temperature range 319-450 deg C and the pressure range 63-207 mmHg.In seasoned vessels the reactions are homogenous, follow a first-order rate law, and are unimolecular.The temperature dependence of the rate constants is given by the following Arrhenius equations for the compounds indicated: 2-(dimethylamino)ethyl acetate, log k(s-1) = (13.90 +/- 0.30) - (220.4 +/- 3.8) kJ*mol-1 (2.303RT)-1; 2-methoxyethyl acetate, log k(s-1) = (12.04 +/- 0.24) -(203.7 +/- 2.9) kJ*mol1- (2.303RT)-1; 2-(methylthio)ethyl acetae, log k(s-1 = (11.27 +/- 0.39) - (179.0 +/- 4.6) kJ*mol-1 (2.303RT)-1; 2-chloroethyl acetate, log k(s-1) = (12.14 +/- 0.66) - (202.0 +/- 8.4)kJ*mol-1 (2.303RT)-1; 2-fluoroethyl acetate, log k(s-1) = (12.68 +/- 0.60) - (211.2 +/- 7.1) kJ*mol-1 (2.303RT)-1; 2-cyanoethylacetate, Log k(s-1) = (11.51 +/- 0.13) - (171.9 +/- 1.7) kJ*mol-1 (2.303RT)-1.The effect of substituents in the gas-phase elimination of β-substituted ethyl acetates may be grouped in three types.The linear correlation of several -I electron-withdrawing groups along strong ? bonds is presented and discussed.A small amount of anchimeric assistance is proposed in the pyrolysis of the 2-(methyltio)ethyl acetate.The experimental data are consistent with the transition state where the Cα-O bond polarization is the rate-determining process.