Untitled

Ganiev, I. M.; Suvorkina, E. S.; Igoshina, A. V.; Sciences, Institute of Organic Chemistry N. N. KabalnovaUfa Research Center of the Russian Academy of; Имашев, У. Б.; Толстиков, Г. А.

doi:10.1023/a:1019605500703

Cited by 3 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results are in agreement with the ability of TPO + to oxidize only primary and secondary alcohols to aldehydes and ketons, respectively, forming the respective hydroxylamine, , which has no appreciable absorption around the absorption peak of TPO, i.e., reactions 15−17. We note that reaction 16 was suggested to take place through the formation of an adduct as an intermediate. , TPO can be regenerated by the reaction of TPO−H with TPO + , but this reaction is too slow at pH 5.7 ( k = 2.6 M -1 s -1 ), and does not compete efficiently with the reaction of TPO + with 0.5 M CH 3 OH ( k 11 = 0.5 M -1 s -1 ) . The reaction of 3-CP with CH 2 (OH)OO • is relatively fast, yet 3-CP is not consumed and G (CH 2 O) ≈ G (H 2 O 2 ) ≈ 5.6.…”

Section: Discussionmentioning

confidence: 91%

“…We note that reaction 16 was suggested to take place through the formation of an adduct as an intermediate. 44,46 TPO can be regenerated by the reaction of TPO-H with TPO + , but this reaction is too slow at pH 5.7 (k ) 2.6 M -1 s -1 ), 47 and does not compete efficiently with the reaction of TPO + with 0.5 M CH 3 OH (k 11 ) 0.5 M -1 s -1 ). 16 The reaction of 3-CP with CH 2 (OH)OO • is relatively fast, yet 3-CP is not consumed and G(CH 2 O) ≈ G(H 2 O 2 ) ≈ 5.6.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics and Mechanism of Peroxyl Radical Reactions with Nitroxides

Goldstein

Samuni

2007

J. Phys. Chem. A

View full text Add to dashboard Cite

Cyclic nitroxides (>NO*) are stable radicals of diverse size, charge, lipophilicility, and cell permeability, which provide protection against oxidative stress via various mechanisms including SOD-mimic activity, oxidation of reduced transition metals and detoxification of oxygen- and nitrogen-centered radicals. However, there is no agreement regarding the reaction of nitroxides with peroxyl radicals, and many controversies in the literature exist. The question of whether nitroxides can protect by scavenging peroxyl radicals is important because peroxyl radicals are formed in biological systems. To further elucidate the mechanism(s) underlying the antioxidative effects of nitroxides, we studied by pulse radiolysis the reaction kinetics of piperidine, pyrrolidine, and oxazolidine nitroxides with several alkyl peroxyl radicals. It is demonstrated that nitroxides mainly reduce alkyl peroxyl radicals forming the respective oxoammonium cations (>N+=O). The most efficient scavenger of peroxyl radicals is 2,2,6,6-tetramethylpiperidine-N-oxyl (TPO), which has the lowest oxidation potential among the nitroxides tested in the present study. The rate constants of peroxyl reduction are in the order CH2(OH)OO*>CH3OO*>t-BuOO*, which correlate with the oxidation potential of these peroxyl radicals. The rate constants for TPO vary between 2.8x10(7) and 1.0x10(8) M-1 s-1 and for 3-carbamoylproxyl (3-CP) between 8.1x10(5) and 9.0x10(6) M-1 s-1. The efficacy of protection of nitroxides against inactivation of glucose oxidase caused by peroxyl radicals was studied. The results demonstrate a clear correlation between the kinetic features of the nitroxides and their ability to inhibit biological damage inflicted by peroxyl radicals.

show abstract

Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Kinetics and Mechanism of Peroxyl Radical Reactions with Nitroxides

Goldstein

Samuni

2007

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…114 Chlorite salts have also been prepared and give mixtures of aldehydes and acids from primary alcohols. 115 Other anions are known but their salts have not been explored as oxidants. 10 All of the stoichiometric oxidation rates are enhanced in the presence of silica gel.…”

Section: Site Selectivitymentioning

confidence: 99%

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

2009

View full text Add to dashboard Cite

The discovery in 1959 of stable nitroxide‐based free radicals such as the prototypical 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) led to their use as electron spin resonance (ESR) spin labels in chemistry, biomedicine, and materials science. These nitroxides are prepared by the oxidation of secondary amines that contain no hydrogen atoms on the alpha‐carbons. The unique redox properties of nitroxides enable their use as oxidants in organic synthesis. The varied preparation and uses of oxoammonium salts as stoichiometric oxidants for alcohols are one subject of this review. Oxoammonium ions as oxidants for alcohols have a number of advantages, for example, the method is heavy‐metal free and some of the reactions can be performed in water or aqueous mixtures. A few side reactions are associated with these oxidations. The most serious is the fast reaction of the oxoammonium ion with free amines The several ways these oxidation reactions can be carried out are discussed in detail. They are: Oxidations using stoichimetric quantities of preformed oxoammonium salts carried out in either acidic, neutral, or basic conditions; reactions in which stoichiometric quantities of oxoammonium salts are generated in situ by disproportionation of a nitroxide in the presence of a strong acid; nitroxide‐catalyzed oxidations using a secondary oxidant; efficient nitroxide‐catalyzed oxidations of primary alcohols to carboxylic acids; and oxidations of primary alcohols or hemiacetals that can lead to lactones.

show abstract

Kinetics of Homogeneous Reactions in Ionic Liquids

AlNashef

Hayyan

2012

International Journal of Electrochemical Science

View full text Add to dashboard Cite

Untitled

Cited by 3 publications

References 6 publications

Kinetics and Mechanism of Peroxyl Radical Reactions with Nitroxides

Kinetics and Mechanism of Peroxyl Radical Reactions with Nitroxides

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

Kinetics of Homogeneous Reactions in Ionic Liquids

Contact Info

Product

Resources

About