Geometrical and Kinetic Isotope Effects on R–H(D)···R Type Intramolecular Hydrogen Bonds (R = CH2, NH, and O) Using a Multi-Component Molecular Orbital Method

2008 ◽  
Vol 81 (7) ◽  
pp. 820-825 ◽  
Author(s):  
Yoko Kikuta ◽  
Takayoshi Ishimoto ◽  
Umpei Nagashima
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Orbital ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Intramolecular Hydrogen Bonds ◽  
Kinetic Isotope ◽  
Intramolecular Hydrogen

AROMATIC SUBSTITUTION: PART VIII. SOME ASPECTS OF THE MECHANISM OF THE TSCHITSCHIBABIN REACTION

1965 ◽  
Vol 43 (4) ◽  
pp. 725-731 ◽  
Author(s):  
R. A. Abramovitch ◽  
F. Helmer ◽  
J. G. Saha
Keyword(s):  
Molecular Orbital ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Aromatic Substitution ◽  
Direct Amination ◽  
Detailed Mechanism ◽  
Methyl Group ◽  
Kinetic Isotope ◽  
Rule Out

The mechanism of the direct amination of pyridines is discussed in terms of both addition–elimination and elimination–addition pathways. The absence of deuterium kinetic isotope effects as well as the orientations observed in such reactions rule out the intervention of 2,3- or 2,6-dehydropyridines. The effect of a 3-methyl group upon the reactivities towards the amide ion of the various nuclear positions in pyridine has been determined. Predictions based on molecular orbital (m.o.) calculations are discussed in terms of the detailed mechanism of this reaction and of the orientations observed.

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