A selectivity study of reaction of the carbonate radical anion with methyl β-d-cellobioside and methyl β-d-glucoside in oxygenated aqueous solutions

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 130-136 ◽  
Author(s):  
Magnus Carlsson ◽  
Johan Lind ◽  
Gábor Merényi
Keyword(s):  
Radical Anion ◽  
Hydrogen Abstraction ◽  
Radical Anions ◽  
Bleaching Agent ◽  
Hydrogen Atoms ◽  
Carbonate Radical ◽  
Abstraction Reaction ◽  
Carbonate Radical Anion ◽  
Hydrogen Abstraction Reaction

Abstract In the presence of oxygen, radiolytically generated carbonate radical anions, CO3 •–, were reacted with methyl β-D-cellobioside and methyl β-D-glucoside. From the ensuing product pattern, it was concluded that CO3 •– abstracts hydrogen atoms predominantly from glucosidic C1–H bonds. This high intramolecular selectivity was rationalised mainly in terms of a polar effect on the transition state of the hydrogen abstraction reaction. The present findings are in sharp contrast to the relative inertness of CO3 •– towards glucosidic C1–H bonds previously observed in cotton linters. The reasons for this discrepancy are discussed in light of a possible future role of CO3 •– as a bleaching agent for pulp.

scholarly journals Cu,Zn-superoxide dismutase-driven free radical modifications: copper- and carbonate radical anion-initiated protein radical chemistry

2008 ◽  
Vol 417 (1) ◽  
pp. 341-353 ◽  
Author(s):  
Dario C. Ramirez ◽  
Sandra E. Gomez-Mejiba ◽  
Jean T. Corbett ◽  
Leesa J. Deterding ◽  
Kenneth B. Tomer ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Active Site ◽  
Radical Anion ◽  
Brain Homogenate ◽  
Experimental Conditions ◽  
Carbonate Radical ◽  
Carbonate Radical Anion ◽  
Protein Radicals ◽  
Mouse Brain Homogenate

The understanding of the mechanism, oxidant(s) involved and how and what protein radicals are produced during the reaction of wild-type SOD1 (Cu,Zn-superoxide dismutase) with H2O2 and their fate is incomplete, but a better understanding of the role of this reaction is needed. We have used immuno-spin trapping and MS analysis to study the protein oxidations driven by human (h) and bovine (b) SOD1 when reacting with H2O2 using HSA (human serum albumin) and mBH (mouse brain homogenate) as target models. In order to gain mechanistic information about this reaction, we considered both copper- and CO3•− (carbonate radical anion)-initiated protein oxidation. We chose experimental conditions that clearly separated SOD1-driven oxidation via CO3•− from that initiated by copper released from the SOD1 active site. In the absence of (bi)carbonate, site-specific radical-mediated fragmentation is produced by SOD1 active-site copper. In the presence of (bi)carbonate and DTPA (diethylenetriaminepenta-acetic acid) (to suppress copper chemistry), CO3•− produced distinct radical sites in both SOD1 and HSA, which caused protein aggregation without causing protein fragmentation. The CO3•− produced by the reaction of hSOD1 with H2O2 also produced distinctive DMPO (5,5-dimethylpyrroline-N-oxide) nitrone adduct-positive protein bands in the mBH. Finally, we propose a biochemical mechanism to explain CO3•− production from CO2, enhanced protein radical formation and protection by (bi)carbonate against H2O2-induced fragmentation of the SOD1 active site. Our present study is important for establishing experimental conditions for studying the molecular mechanism and targets of oxidation during the reverse reaction of SOD1 with H2O2; these results are the first step in analysing the critical targets of SOD1-driven oxidation during pathological processes such as neuroinflammation.

The hydrogen abstraction reaction H + C2H6 → H2(v,j) + C2H5. Part II. Theoretical kinetics and dynamics study

2019 ◽  
Vol 21 (24) ◽  
pp. 13356-13367 ◽  
Author(s):  
Joaquin Espinosa-Garcia ◽  
Jose C. Corchado
Keyword(s):  
Low Temperatures ◽  
Hydrogen Abstraction ◽  
Abstraction Reaction ◽  
Kinetics And Dynamics ◽  
Hydrogen Abstraction Reaction

Two important issues motivated the present study: the role of the tunnelling contribution at low temperatures and the role of the alkyl fragment in the dynamics.

Role of Hydrogen Abstraction Reaction in Photocatalytic Decomposition of High Energy Density Materials

2016 ◽  
Vol 120 (43) ◽  
pp. 24835-24846
Author(s):  
Roman Tsyshevsky ◽  
Anton S. Zverev ◽  
Anatoly Y. Mitrofanov ◽  
Natalya N. Ilyakova ◽  
Mikhail V. Kostyanko ◽  
...  
Keyword(s):  
Energy Density ◽  
Hydrogen Abstraction ◽  
High Energy ◽  
High Energy Density ◽  
Photocatalytic Decomposition ◽  
Abstraction Reaction ◽  
High Energy Density Materials ◽  
Hydrogen Abstraction Reaction

Polar Radicals. VIII. Kinetic Studies on the Mechanism of the Vapor Phase Bromination of 1-Chlorobutane. The Role of Reversible Hydrogen Abstraction

1975 ◽  
Vol 53 (14) ◽  
pp. 2202-2209 ◽  
Author(s):  
Dennis D. Tanner ◽  
Tony Pace ◽  
Tameichi Ochiai
Keyword(s):  
Vapor Phase ◽  
Hydrogen Bromide ◽  
Hydrogen Abstraction ◽  
Kinetic Studies ◽  
Abstraction Reaction ◽  
Substituted Alkanes ◽  
Kinetics Of ◽  
Hydrogen Abstraction Reaction ◽  
General Method

A general method for the evaluation of the kinetics of the vapor phase brominations of alkanes and substituted alkanes is presented. The method is applied to the bromination of 1-chlrobutane.The hydrogen abstraction reaction and its reversal are both found to be deactivated by the polar influence of the substituent; the effect, as predicted, falls off as the distance of the substituent from the C—H bond involved increases. In the vapor phase bromination of 1-chlorobutane, because of this deactivated reversal, transfer with hydrogen bromide cannot compete (< 10%) with transfer with molecular bromine.There was no evidence for anchimeric assistance by the neighboring chlorine atom during hydrogen abstraction.

Degradation and transformation of bisphenol A in UV/Sodium percarbonate: Dual role of carbonate radical anion

2020 ◽  
Vol 171 ◽  
pp. 115394 ◽  
Author(s):  
Jiong Gao ◽  
Xiaodi Duan ◽  
Kevin O’Shea ◽  
Dionysios D. Dionysiou
Keyword(s):  
Bisphenol A ◽  
Radical Anion ◽  
Dual Role ◽  
Carbonate Radical ◽  
Sodium Percarbonate ◽  
Carbonate Radical Anion

Role of an ethyl radical and the problem of HF(v) bimodal vibrational distribution in the F(2P) + C2H6 → HF(v) + C2H5 reaction

2018 ◽  
Vol 20 (41) ◽  
pp. 26634-26642 ◽  
Author(s):  
J. Espinosa-Garcia ◽  
M. Garcia-Chamorro
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Energy Surface ◽  
Theoretical Study ◽  
Hydrogen Abstraction ◽  
Abstraction Reaction ◽  
Classical Trajectories ◽  
Hydrogen Abstraction Reaction

A theoretical study of the dynamics of the F(2P) + C2H6 hydrogen abstraction reaction was presented using quasi-classical trajectories propagated on an ab initio fitted global potential energy surface, PES-2018.

scholarly journals One- and Two-Electron Oxidations of β-Amyloid25-35 by Carbonate Radical Anion (CO3•−) and Peroxymonocarbonate (HCO4−): Role of Sulfur in Radical Reactions and Peptide Aggregation

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 961
Author(s):  
Antonio Francioso ◽  
Alessia Baseggio Conrado ◽  
Carla Blarzino ◽  
Cesira Foppoli ◽  
Elita Montanari ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Anion ◽  
Carbonate Radical ◽  
Methionine Residue ◽  
Amyloid Aβ ◽  
Radical Generation ◽  
Oxidation Of Methionine ◽  
The One ◽  
Carbonate Radical Anion

The β-amyloid (Aβ) peptide plays a key role in the pathogenesis of Alzheimer’s disease. The methionine (Met) residue at position 35 in Aβ C-terminal domain is critical for neurotoxicity, aggregation, and free radical formation initiated by the peptide. The role of Met in modulating toxicological properties of Aβ most likely involves an oxidative event at the sulfur atom. We therefore investigated the one- or two-electron oxidation of the Met residue of Aβ25-35 fragment and the effect of such oxidation on the behavior of the peptide. Bicarbonate promotes two-electron oxidations mediated by hydrogen peroxide after generation of peroxymonocarbonate (HCO4−, PMC). The bicarbonate/carbon dioxide pair stimulates one-electron oxidations mediated by carbonate radical anion (CO3•−). PMC efficiently oxidizes thioether sulfur of the Met residue to sulfoxide. Interestingly, such oxidation hampers the tendency of Aβ to aggregate. Conversely, CO3•− causes the one-electron oxidation of methionine residue to sulfur radical cation (MetS•+). The formation of this transient reactive intermediate during Aβ oxidation may play an important role in the process underlying amyloid neurotoxicity and free radical generation.

Thermochemical and kinetic studies of hydrogen abstraction reaction from C16H10 isomers by H atoms

2021 ◽  
Vol 1201 ◽  
pp. 113257
Author(s):  
Dorra Khiri ◽  
Sonia Taamalli ◽  
Duy Quang Dao ◽  
Thanh-Binh Nguyen ◽  
Laurent Gasnot ◽  
...  
Keyword(s):  
Hydrogen Abstraction ◽  
Kinetic Studies ◽  
Abstraction Reaction ◽  
Hydrogen Abstraction Reaction
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