On the regioselectivity of free radical processes ; reactions of benzoyloxy, phenyl and t-butoxy radicals with some α,β-unsaturated esters

1983 ◽  
Vol 36 (8) ◽  
pp. 1573 ◽  
Author(s):  
G Moad ◽  
E Rizzardo ◽  
DH Solomon
Keyword(s):  
Free Radical ◽  
Double Bond ◽  
Methyl Methacrylate ◽  
Methyl Acrylate ◽  
Hydrogen Abstraction ◽  
Free Radical Processes ◽  
Unsaturated Esters ◽  
Factors Influencing ◽  
Radical Processes

The reactions of three electrophilic radicals, benzoyloxy, phenyl, and t-butoxy, have been examined with a series of α, β unsaturated esters; methyl acrylate, methyl methacrylate, and methyl crotonate. For the three monomers the ratio of hydrogen abstraction to double bond addition was found to increase and the ratio of head against tail addition to decrease in the series: benzoyloxy; phenyl; t-butoxy. Relative rates for these reactions have been determined and the factors influencing the mode of reaction are discussed.

Oxidations of aromatic amines by superoxide ion

1984 ◽  
Vol 37 (4) ◽  
pp. 845 ◽  
Author(s):  
G Crank ◽  
MIH Makin
Keyword(s):  
Free Radical ◽  
Aromatic Amines ◽  
Hydrogen Abstraction ◽  
Biological Significance ◽  
Oxidizing Agent ◽  
Superoxide Ion ◽  
Free Radical Processes ◽  
Radical Processes

Superoxide ion acts as a mild and highly selective oxidizing agent for aromatic amines. Aniline and α-naphthylamine were not oxidized, but β-naphthylamine formed dibenzo[a,h]phenazine, dibenzo- [a,i]phenazine and 2,2'-azonaphthalen-1-ol. o-and p-Diamines are oxidized to diaminoazobenzenes but m-diamines are unreactive. Similarly o- and p-aminophenols are oxidized to dihydroxyazo- benzenes but m-aminophenols are unaffected, and o-mercaptoaniline forms the disulfide. The oxidations are considered to be free-radical processes, initiated by hydrogen abstraction by superoxide from the substrates. The biological significance of the results is discussed.

Adaptogenic correction of free radical brain damage in subchronic exposure to sodium fl uoride

2020 ◽  
pp. 381-386
Author(s):  
A. G. Zhukova ◽  
L. G. Gorokhova ◽  
A. S. Kazitskaya ◽  
T. K. Yadykina ◽  
N. N. Mikhailova ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Free Radical ◽  
Brain Tissue ◽  
Free Radical Oxidation ◽  
Radical Oxidation ◽  
Free Radical Processes ◽  
Subchronic Exposure ◽  
Antioxidant Defense Enzymes ◽  
Radical Processes ◽  
Complex Drug

Introduction. Fluorine compounds in small doses, but with prolonged exposure, cause various disorders in organs at the cellular and molecular levels. Activation of free-radical processes plays an important role in the damaging eff ect of fl uorides. Th erefore, one of the most eff ective ways to limit fl uorine-induced damage is to directly aff ect free-radical processes using herbal preparations with antioxidant properties.The aim of the study is to study the eff ect of a dihydroquercetin-based drug on the activity of free radical processes in brain tissue under subchronic exposure to sodium fl uoride (NaF).Materials and methods. Th e work was performed on white male laboratory rats weighing 200-250 g. Th e rats were divided into 3 groups: 1 — control; 2 — rats with chronic exposure to sodium fl uoride (NaF) for 9 weeks; 3 — rats receiving a NAF solution with simultaneous administration of a complex drug based on dihydroquercetin at a dose of 3 mg/kg in 1% starch gel for 3, 6 and 9 weeks. The activity of free radical oxidation and antioxidant defense enzymes — superoxide dismutase (SOD) and catalase-was determined in the cerebral cortex. Th e level of expression of hypoxia-induced transcription factor HIF — 1A and inducible forms of proteins HSP72 and HSP32 were determined in the cytosolic fraction of brain tissue.Results. In the early stages of subchronic fl uoride exposure (1-3 weeks), the expression of protective proteins HIF-1α, HSP72, HSP32 and catalase was shown in the rat cortex, as a result of which the activity of free-radical processes was maintained at the control level. An increase in the timing of fl uoride intake to 9 weeks led to a decrease in antioxidant protection and signifi cant activation of free radical oxidation in brain tissue. Daily administration of a complex drug with dihydroquercetin for 3, 6 and 9 weeks to rats with subchronic fl uoride exposure led to a decrease in the severity of pro- and antioxidant balance disorders in the cerebral cortex. At the same time, the greatest protective eff ect of dihydroquercetin with fl uoride exposure was manifested by the 9th week of its administration.Conclusions. When subchronic intake of fl uorides in the body, the drug based on dihydroquercetin has a neuroprotective eff ect, which is manifested by an increase in the activity of antioxidant enzymes of fr ee radical oxidation and catalase and the resistance of the cortex to induced fr ee radical oxidation.

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