4209-18-1Relevant academic research and scientific papers
An efficient procedure for the synthesis of phenacyl and benzyl azolium salts using fluorous alcohols
Khalafi-Nezhad, Ali,Panahi, Farhad,Yousefi, Reza,Gholamalipour, Yasaman,Sarrafi, Sina
, p. 1189 - 1196 (2014/08/05)
An efficient procedure for the synthesis of phenacyl and benzyl azolium salts in 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoroisopropanol as fluorous alcohols have been developed. This synthetic methodology has some advantages with the respect to yield, atom efficiency, solvent and reagents used and wastes generated when compared to the currently in use methods. Using this procedure, a range of phenacyl and benzyl azolium salts can be synthesized with good to excellent yields. The pure salts are separated from the reaction mixture by simple filtration and washing with dry ether.
BASE-CATALYZED OXIDATION OF 2-(α-HYDROXYBENZYL)THIAMINE BY MOLECULAR OXYGEN
Vovk, A. I.,Murav'eva, I. V.
, p. 119 - 122 (2007/10/03)
Oxidation of 2-(α-hydroxybenzyl)thiamine by molecular oxygen in the presence of an acetate buffer in methanol includes formation of an intermediate enamine and its subsequent oxidation with concurrent protonation.Using the dependence of the reciprocal rate constant for acetate-catalyzed oxidation on /-> the values of k1 and k-1/k2 have been calculated.Comparison of oxidation kinetics of 2-(α -hydroxybenzyl)thiamine, 2-(α-hydroxybenzyl)-3- benzyl-4-methyl-5-(2-hydroxyethyl)thiazolium chloride, and 2(α-hydroxybenzyl)-3-benzyl- 4-methylthiazolium chloride indicates that the reaction of the intermediate enamine with O2 is governed by the 3- and 5-substituents.It is assumed that the 5-hydroxyethyl group causes steric hindrance, and the amino group in position 4 of the pyrimidine fragment favors deprotonation of the Cα-hydroxy group.
OXIDATIVE DECOMPOSITION OF 2-(α-HYDROXYBENZYL)THIAMINE UNDER THE ACTION OF A BASE AND SUBSTITUTED QUINONES
Vovk, A. I.,Murav'eva, I. V.
, p. 937 - 940 (2007/10/02)
The reaction of 2-(α-hydroxybenzyl)thiamine and its thiazolium structural analogs with substituted quinones in the presence of acetate buffer in deaerated methanolic solutions at 27 deg C and ionic strength of 0.15 is characterized by first-order kinetics with respect to the thiazolium salt and the acetate and by zero-order kinetics with resoect to quinone.The rate constant of the reaction catalyzed by the basic component of the buffer decreases in the following series of oxidants: 2-methyl-5-isopropyl-p-benzoquinone, trimethyl-p-benzoquinone, tetramethyl-p-benzoquinone.It was supposed that fast reversible formation of a complex between the deprotonated 2-(α-hydroxybenzyl)thiazole and the oxidant precedes electron transfer to the quinone.In the one-electron transfer stage, which determines the overall reaction rate, the 5-hydroxyethyl substituent exerts an adverse effect for steric reasons.
MODEL REACTIONS OF PYRUVATEDECARBOXYLASE: MECHANISMS OF THE FORMATION OF AN ALDEHYDE FROM THE 2-(α-HYDROXYBENZYL)THIAZOLUM ION
Vovk, A. I.,Murav'eva, I. V.
, p. 2407 - 2412 (2007/10/02)
In methanol and methanol-dichloroethane mixtures the rate of the decomposition of 3-benzyl-2-(α-hydroxybenzyl)-4-methylthiazolium iodide exceeds the rate of the decomposition of the corresponding chloride.Values of the rate constants of decomposition into benzaldehyde and thiazolium salt rise with fall in the solvating power of the solvent.The relation of the decomposition rate constant to the concentration of the alkali interacting with the 2-(α=hydroxybenzyl)thiazolium ion is nonlinear.The probable intermediate formed in the decomposition of thw 2-(α-hydroxybenzyl)thiazolium ion into benzaldehyde and a thiazolium salt may be a tetrahedral compound formed as a result of nucleophilic attack by the hydroxyl ion in the 2 position of the thiazolium ring.
CATALYTIC CYCLOPHANES: A HIGHLY EFFICIENT MODEL FOR PYRUVATE OXIDASE
Jimenez, Leslie,Diederich, Francois
, p. 2759 - 2762 (2007/10/02)
The thiazolium macrocycle 1 is prepared by a novel synthetic route to monofunctionalized cyclophanes.Host 1 is a very efficient catalyst for the oxidation of aromatic aldehydes to carboxylic acids in the presence of potassium ferricyanide.
