Deuterium exchange studies

Cations (12), (13), and (14) represent the three ways in which proton may add to pyrrole. Twenty-five years ago, Koizumi and Titani earned out a series of deuterium exchange studies and... 

Cis-trans isomerization occurs either by formation of a half-hydrogenated state (Horiuti-Polanyi mechanism) followed by rotation around the newly formed single bond and abstraction of an appropriate hydrogen onto the surface or by double bond migration (either Horiuti-Polanyi or Jt-allyl) from a cis (trans) position to an adjacent trans (cis) position (deuterium exchange studies favor the rotation mechanism). 

Hvidt, A. and Wallevik, K. (1972). Conformational changes in human serum albumin as revealed by hydrogen-deuterium exchange studies. J. Biol. Chem. 247, 1530-1535... 

Andersen M.D., Shaffer J., Jennings P.A., Adams J.A. Structural characterization of protein kinase A as a function of nucleotide binding. Hydrogen-deuterium exchange studies using matrix-assisted laser desorption ionization-time of flight mass spectrometry detection. J. Biol. Chem. 2001, 276, 14204-14211. 

Deuterium exchange studies on decaborane and other boranes indicate acidic character of bridge hydrogens. They react with bases undergoing proton abstraction reactions ... 

The third test of the conjugate base mechanism that we put forward was based on the idea that the first step should be written as an equilibrium, and the reaction rate should show specific hydroxide ion catalysis. If this is indeed in equilibrium, and deuterium exchange studies say that it must be, then the rate of the reaction must depend on the hydroxide ion concentration, and on nothing else. 

Double Resonance Spin Decoupling and Deuterium Exchange Studies of Cimetidine... 

The fluorination of quinoline was performed in a microstructured reactor operated in the annular-flow regime, which contained one microchannel with two consecutive feeds for gas and liquid [311,312]. The role of the solvent was large. The reaction was totally unselective in acetonitrile and gave only tarlike products. With formic acid, a mixture of mono- and polyfluorinated products besides tar was formed. No tar formation was observed with concentrated sulfuric acid as solvent at 0-5 °C. In this way, a high selectivity of about 91% at medium conversion was achieved. Substitution was effective only in the electron-rich benzenoid core and not in the electron-poor pyridine-type core. The reactivity at the various positions in the quinoline molecule is 5 > 8 > 6 and thus driven by the vicinity to the heteroatom nitrogen that corresponds to the electrophilic reactivity known from proton/deuterium exchange studies in strong acid media. 

However, fi adsorption on catalysts is also supported by deuterium exchange studies of thiophene. When thiophene and D2 are passed over Mo-based HDS catalysts at temperatures below which substantial HDS occurs, the thiophene protons exchange with deuterium. This exchange occurs much more rapidly at the 2- and 5-positions than at the 3- and 4-sites. When CpRu(jj -T)+ (equation 9) is dissolved in CD3OD in the presence of OD at 23 °C, the 2,5-hydrogens of thiophene... 

Kursanov, D. N., Parnes, Z. N. Mechanism of pinacolone rearrangement by deuterium exchange study. Zh. Obshch. Khim. 1957, 27, 737-739. 

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