Radical Chain Reduction via Carbon Dioxide Radical Anion (CO2•–)

2021 ◽  
Author(s):  
Cecilia M. Hendy ◽  
Gavin C. Smith ◽  
Zihao Xu ◽  
Tianquan Lian ◽  
Nathan T. Jui
Keyword(s):  
Carbon Dioxide ◽  
Radical Anion ◽  
Radical Chain

scholarly journals Protein hydroperoxides can give rise to reactive free radicals

1995 ◽  
Vol 305 (2) ◽  
pp. 643-649 ◽  
Author(s):  
M J Davies ◽  
S Fu ◽  
R T Dean
Keyword(s):  
Free Radicals ◽  
Amino Acid ◽  
Radical Anion ◽  
Similar Process ◽  
Side Chain ◽  
Radical Species ◽  
Radical Chain ◽  
Chain Reactions ◽  
Oxygen Yield ◽  
Rearrangement Processes

Proteins damaged by free-radical-generating systems in the presence of oxygen yield relatively long-lived protein hydroperoxides. These hydroperoxides have been shown by e.p.r. spectroscopy to be readily degraded to reactive free radicals on reaction with iron(II) complexes. Comparison of the observed spectra with those obtained with free amino acid hydroperoxides had allowed identification of some of the protein-derived radical species (including a number of carbon-centred radicals, alkoxyl radicals and a species believed to be the CO2 radical anion) and the elucidation of novel fragmentation and rearrangement processes involving amino acid side chains. In particular, degradation of hydroperoxide functions on the side chain of glutamic acid is shown to result in decarboxylation at the side-chain carboxy group via the formation of the CO2 radical anion; the generation of an identical radical from hydroperoxide groups on proteins suggests that a similar process occurs with these molecules. In a number of cases these fragmentation and rearrangement reactions give rise to further reactive free radicals (R., O2-./HO2., CO2-.) which may act as chain-carrying species in protein oxidations. These studies suggest that protein hydroperoxides are capable of initiating further radical chain reactions both intra- and inter-molecularly, and provide information on some of the fundamental mechanisms of protein alteration and side-chain fragmentation.

scholarly journals Radiolytic chain reaction of m-iodophenyl .BETA.-D-glucoside with radical anion of carbon dioxide produced from formate.

1984 ◽  
Vol 48 (3) ◽  
pp. 817-819 ◽  
Author(s):  
TAKASHI KOMIYA ◽  
TETSUYA YAMADA ◽  
SHOZO NARA ◽  
SHUNRO KAWAKISHI ◽  
Mitsuo NAMIKI
Keyword(s):  
Carbon Dioxide ◽  
Radical Anion ◽  
Chain Reaction

scholarly journals Biomimetic Ketone Reduction by Disulfide Radical Anion

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5429
Author(s):  
Sebastian Barata-Vallejo ◽  
Konrad Skotnicki ◽  
Carla Ferreri ◽  
Bronislaw Marciniak ◽  
Krzysztof Bobrowski ◽  
...  
Keyword(s):  
Radical Anion ◽  
Radical Mechanism ◽  
Cyclic Ketones ◽  
High Concentration ◽  
Radical Chain ◽  
Ketyl Radical ◽  
Electron Reduction ◽  
The One ◽  
Key Steps ◽  
Radical Chain Reaction

The conversion of ribonucleosides to 2′-deoxyribonucleosides is catalyzed by ribonucleoside reductase enzymes in nature. One of the key steps in this complex radical mechanism is the reduction of the 3′-ketodeoxynucleotide by a pair of cysteine residues, providing the electrons via a disulfide radical anion (RSSR•−) in the active site of the enzyme. In the present study, the bioinspired conversion of ketones to corresponding alcohols was achieved by the intermediacy of disulfide radical anion of cysteine (CysSSCys)•− in water. High concentration of cysteine and pH 10.6 are necessary for high-yielding reactions. The photoinitiated radical chain reaction includes the one-electron reduction of carbonyl moiety by disulfide radical anion, protonation of the resulting ketyl radical anion by water, and H-atom abstraction from CysSH. The (CysSSCys)•− transient species generated by ionizing radiation in aqueous solutions allowed the measurement of kinetic data with ketones by pulse radiolysis. By measuring the rate of the decay of (CysSSCys)•−at λmax = 420 nm at various concentrations of ketones, we found the rate constants of three cyclic ketones to be in the range of 104–105 M−1s−1 at ~22 °C.

Peroxynitrite-Mediated Decarboxylation of Pyruvate to Both Carbon Dioxide and Carbon Dioxide Radical Anion

1997 ◽  
Vol 10 (7) ◽  
pp. 786-794 ◽  
Author(s):  
Jeannette Vásquez-Vivar ◽  
Ana Denicola ◽  
Rafael Radi ◽  
Ohara Augusto
Keyword(s):  
Carbon Dioxide ◽  
Radical Anion

Radical reactions of p-Nitrobenzylidene dichloride with lithium 2-nitropropan-2-ide. Consecutive SRN1 and ERC1 reactions

1976 ◽  
Vol 29 (12) ◽  
pp. 2631 ◽  
Author(s):  
DJ Freeman ◽  
RK Norris
Keyword(s):  
Radical Anion ◽  
Anion Radical ◽  
Lithium Salt ◽  
Substituent Effects ◽  
Radical Reactions ◽  
Elimination Reaction ◽  
Radical Chain ◽  
Radical Processes

The reaction of p-nitrobenzylidene dichloride with the lithium salt of 2-nitropropane gives initially the monosubstituted compound, p- NO2C6H4CH(Cl)CMe2NO2, by a radical-anion radical chain, SRN1 process. This compound then undergoes a radical-anion radical chain elimination reaction giving the styrene, p-NO2C6H4CH=CMe2, and the dimer of 2- nitropropane, Me2C(NO2)CMe2NO2. This latter reaction, which is designated ?ERC1?, also occurs in competition with an E2 reaction in the reaction of the methanesulphonate, p-NO2C6H4CH(OMs)CMe2NO2, with the 2- nitropropan-2-ide ion giving the above styrene and the enol methanesulphonate, p-NO2C6H4C(OMs)=CMe2, respectively. Catalytic, inhibition, and substituent effects are used to confirm the operation of these radical processes.

Reactions of carbon dioxide radical anion with substituted benzenes

2001 ◽  
Vol 14 (5) ◽  
pp. 300-309 ◽  
Author(s):  
Janina A. Rosso ◽  
Sonia G. Bertolotti ◽  
André M. Braun ◽  
Daniel O. Mártire ◽  
Mónica C. Gonzalez
Keyword(s):  
Carbon Dioxide ◽  
Radical Anion ◽  
Substituted Benzenes
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