Structure-reactivity correlations for aza-arenes. Proton affinities, pKa values, hydrogen-deuterium exchange rates and radical-induced13C shifts

1995 ◽  
Vol 8 (7) ◽  
pp. 496-505 ◽  
Author(s):  
Jens Spanget-Larsen
Keyword(s):  
Exchange Rates ◽  
Deuterium Exchange ◽  
Hydrogen Deuterium Exchange ◽  
Proton Affinities ◽  
Pka Values ◽  
Hydrogen Deuterium ◽  
Aza Arenes

scholarly journals The stereospecificity and catalytic efficiency of the tryptophan synthase-catalysed exchange of the α-protons of amino acids

2004 ◽  
Vol 381 (3) ◽  
pp. 847-852 ◽  
Author(s):  
Máire E. NíBEILLIÚ ◽  
J. Paul G. MALTHOUSE
Keyword(s):  
Amino Acids ◽  
Exchange Rates ◽  
Catalytic Efficiency ◽  
Deuterium Exchange ◽  
Proton Exchange ◽  
Tryptophan Synthase ◽  
Hydrogen Deuterium Exchange ◽  
Pka Values ◽  
First Order ◽  
Hydrogen Deuterium

13C-NMR has been used to follow the tryptophan synthase (EC 4.2.1.20) catalysed hydrogen–deuterium exchange of the pro-2R and pro-2S protons of [2-13C]glycine at pH 7.8. 1H-NMR has also been used to follow the tryptophan-synthase-catalysed hydrogen–deuterium exchange of the α-protons of a range of L- and D-amino acids at pH 7.8. The pKa values of the α-protons of these amino acids have been estimated and we have determined whether or not their exchange rates can be predicted from their pKa values. With the exception of tryptophan and norleucine, the stereospecificities of the first-order α-proton exchange rates are independent of the size and electronegativity of the amino acid R-group. Similar results are obtained with the second-order α-proton exchange rates, except that both L-tryptophan and L-serine have much higher stereospecificities than all the other amino acids studied.

pH and Urea Dependence of Amide Hydrogen−Deuterium Exchange Rates in the β-Trefoil Protein Hisactophilin†

Biochemistry ◽  
2002 ◽  
Vol 41 (4) ◽  
pp. 1182-1194 ◽  
Author(s):  
R. Scott Houliston ◽  
Chengsong Liu ◽  
Laila M. R. Singh ◽  
Elizabeth M. Meiering
Keyword(s):  
Exchange Rates ◽  
Deuterium Exchange ◽  
Hydrogen Deuterium Exchange ◽  
Amide Hydrogen ◽  
Hydrogen Deuterium

Aryl Carbanions. A 13C Nuclear Magnetic Resonance Study of Deuterium Exchange in Acenaphthenes and Related Aromatic Hydrocarbons

1973 ◽  
Vol 51 (17) ◽  
pp. 2884-2892 ◽  
Author(s):  
D. H. Hunter ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Exchange Rates ◽  
Aromatic Hydrocarbons ◽  
Nuclear Magnetic Resonance Study ◽  
Deuterium Exchange ◽  
Hydrogen Deuterium Exchange ◽  
Magnetic Resonance Study ◽  
Ring Strain ◽  
13C Nuclear Magnetic Resonance ◽  
Hydrogen Deuterium

The base-catalyzed hydrogen–deuterium exchange rates for the aromatic and benzylic centers in acenaphthene, 2,3-dihydrophenalene, 1,8-dimethylnaphthalene, 1,1,2,2,-tetramethylacenaphthene, and diphenylmethane have been determined using 13C n.m.r. The exchange rates serve as a probe of carbanion stability and reactivity, clearly indicating the importance of ring strain effects on carbanion stability.

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