74415-02-4Relevant articles and documents
Equilibrium of acyl transfer between pyridine N-oxides and their acylonium salts
Rubachenko,Schroeder,Chotii,Kovalenko,Red'ko,Lenska
, p. 1241 - 1246 (2008/12/22)
Transfer of acyl groups from N-acyloxypyridinium salts to pyridine N-oxides in acetonitrile was studied. The equilibrium constants of acyl exchange were determined. These quantities vary in the range covering eight orders of magnitude, depending on the st
The Rate and Equilibrium Constants for N-, O-Acyl Transfer
Rybachenko,Chotii,Kovalenko,Shreder
, p. 1695 - 1698 (2007/10/03)
Reactions with dimethylcarbamoyl group transfer from N-acylpyridinium salts to pyridine N-oxides and from N-acyloxypyridinium salts to pyridines in acetonirile solutions were studied. Their rate and equilibrium constants and activation parameters were determined. The reactions were shown to be one-step and to follow the SN2 mechanism. Equations relating the rate and equilibrium parameters of the N-O and O-N acyl transfer reactions to the basicity of the nucleophile and outgoing group were obtained.
Equilibrium of acetyl transfer between pyridine N-Oxides and their acetylonium salts
Rybachenko,Chotii,Kovalenko,Schroeder
, p. 786 - 788 (2007/10/03)
The equilibrium constants of acetyl transfer between O-acetylonium salts of a series of pyridine N-oxides and 4-(4-dimethylaminostyryl)pyridine N-oxide in acetonitrile and methylene chloride were determined. The equilibrium constants correlate with the ac
Acetyl exchange between pyridine N-oxides in acetonitrile solutions: An attempt to apply the Marcus equation to acetyl transfer
Rybachenko,Schroeder,Chotii,Titov,Kovalenko,Leska,Grebenyuk
, p. 1608 - 1615 (2007/10/03)
Forty-three (including eight identical) reactions of acetyl transfer from N-acetyloxypyridinium salts to pyridine N-oxides in acetonitrile solutions were studied. The rate constants k2 vary in the range 107-10-1 1 mol-1 s-1; the equilibrium constants K, in the range 107-10-7; the activation enthalpy ΔH≠, in the range 17-30 kJ mol-1; the activation entropy -ΔS≠, in the range 60-85 J mol-1 K-1; and the heat of reaction -ΔH0, within ±50 kJ mol-1. All reactions occur in a single stage by the concerted SN2 mechanism with a low degree of bond cleavage in the transition state. The rate and equilibrium of the acetyl exchange are satisfactorily described by the Bronsted equation. The quality of predicting the reactivity is substantially improved by introducing into the correlation equation a second parameter, the rates of identical reactions.
THE MOLECULAR COMPLEX OF 4-(N-PYRIDINIUM)PYRIDINE-N-OXIDE CHLORIDE WITH TETRACYANOETHYLENE IN THE SYNTHESIS OF SUBSTITUTED PYRIDINE N-OXIDES
Rodina, L. L.,Ryzhakov, A. V.,Alekseeva, O. O.
, p. 157 - 159 (2007/10/03)
The structure of the complex of 4-(N-pyridinium)pyridine-N-oxide chloride with tetracyanoethylene was studied by 13C NMR spectroscopy.The results of the investigation, suggesting the use of this complex in the synthesis of substituted pyridine derivatives, were confirmed experimentally by its reaction with oxygen and with nitrogen-containing nucleophiles.
Kinetics of Hydrolysis and Aminolysis of 1-Methoxycarbonylpyridinium Ions
Battye, Peter J.,Ihsan, Ekmel M.,Moodie, Roy B.
, p. 741 - 748 (2007/10/02)
Rate constants are reported for reactions of 1-methoxycarbonylpyridinium ions in aqueous solution with water, hydroxide ion, and primary and secondary amines.The water reaction is general base-catalysed; solvent isotope effects are reported.Both the water and hydroxide reactions proceed with rate-determining formation of tetrahedral intermediate. with the primary and secondary amines, either formation or breakdown of a tetrahedral intermediate is rate determining, depending upon the ring substituent.Structure-reactivity plots lead to estimates of relative leavig-group abilities, which are compared with others in the literature.Hydroxide-ion catalysed aminolysis is observed in some cases, and occurs by a concerted mechanism.
