Anomeric and conformational deuterium isotope effects in saturated sulphur and nitrogen heterocycles

1987 ◽  
pp. 595 ◽  
Author(s):  
Frank A. L. Anet ◽  
Max Kopelevich
Keyword(s):  
Isotope Effects ◽  
Nitrogen Heterocycles ◽  
Deuterium Isotope Effects

Quaternary Nitrogen Heterocycles. II. Kinetics of Reversible Pseudobase Formation from N-Methyl Heterocyclic Cations

1973 ◽  
Vol 51 (12) ◽  
pp. 1965-1972 ◽  
Author(s):  
John W. Bunting ◽  
William G. Meathrel
Keyword(s):  
Isotope Effects ◽  
Nitrogen Heterocycles ◽  
Activation Parameters ◽  
Hydroxide Ion ◽  
Quaternary Nitrogen ◽  
Equilibrium And Kinetics ◽  
Temperature Dependences ◽  
Deuterium Isotope Effects ◽  
Heterocyclic Cations ◽  
Kinetics Of

The kinetics of the formation and decomposition of the pseudobases from the 2-methyl-4-nitroisoquinolinium, 10-methylacridinium, and 10-methyl-9-phenylacridinium ions have been studied. The pH–rate profiles of these reactions indicate that for each of these ions, pseudobase formation may kinetically involve either attack of a water molecule or of hydroxide ion on the heterocyclic cation depending upon the pH of the reaction. Pseudobase decomposition to the cation may occur through either the neutral or protonated pseudobase species or their kinetic equivalents. The temperature dependences of the equilibrium and kinetics are reported for each ion, and deuterium isotope effects for the reactions of the 2-methyl-4-nitroisoquinolinium ion have been measured. Possible mechanisms for the reactions are discussed on the basis of the observed activation parameters and isotope effects and are compared with related reactions.

Mechanism of hydration and isomerisation of 4-ethylidene-2,6-di-tert-butyl-2,5-cyclohexadien-1-one. Kinetics, acid-base catalysis and solvent deuterium isotope effects

1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček
Keyword(s):  
Aqueous Medium ◽  
Rate Equation ◽  
Kinetic Data ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quinone Methide ◽  
Reaction Products ◽  
Acid Base ◽  
Deuterium Isotope Effects ◽  
Hydroxybenzyl Alcohol

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.

Hydrogen/Deuterium-Isotope Effects on NMR Chemical Shifts and Symmetry of Homoconjugated Hydrogen-Bonded Ions in Polar Solution

2000 ◽  
Vol 122 (51) ◽  
pp. 12878-12879 ◽  
Author(s):  
Parwin Schah-Mohammedi ◽  
Ilja G. Shenderovich ◽  
Carsten Detering ◽  
Hans-Heinrich Limbach ◽  
Peter M. Tolstoy ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Isotope Effects ◽  
Polar Solution ◽  
Nmr Chemical Shifts ◽  
Hydrogen Deuterium ◽  
Deuterium Isotope Effects ◽  
Hydrogen Bonded
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