Oxidation of alkane and alkene moieties with biologically inspired nonheme iron catalysts and hydrogen peroxide: from free radicals to stereoselective transformations

2017 ◽  
Vol 22 (2-3) ◽  
pp. 425-452 ◽  
Author(s):  
Giorgio Olivo ◽  
Olaf Cussó ◽  
Margarida Borrell ◽  
Miquel Costas
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radicals ◽  
Nonheme Iron ◽  
Iron Catalysts ◽  
Biologically Inspired

The effect of cation concentration on the nitrogen splitting constant of nitroxide free radicals

1990 ◽  
Vol 55 (10) ◽  
pp. 2377-2380
Author(s):  
Hamza A. Hussain
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Bonding ◽  
Free Radicals ◽  
Esr Spectroscopy ◽  
The Other ◽  
Tetraethylammonium Bromide ◽  
Splitting Constant ◽  
The One ◽  
Positively Charged ◽  
Two Equilibria

Nitroxide free radicals prepared from diethylamine, piperidine and pyrrolidine by oxidation with hydrogen peroxide were studied by ESR spectroscopy. The changes in the 14N splitting constant (aN) caused by the addition of KBr or tetraethylammonium bromide were measured in dependence on the concentration of the ions. For diethylamine nitroxide and piperidine nitroxide, the results are discussed in terms of two equilibria: the one, involving the anion, is associated with a gain or loss of hydrogen bonds to the nitroxide oxygen atom, the other is associated with the formation of solvent shared units involving the cation, which results in changes in the hydrogen bonding strenght. The large increase in the aN value in the case of pyrrolidine nitroxide is explained in terms of an interaction from one side of the positively charged N atom; the increase in aN in the case of diethylamine and piperidine nitroxides is explained in terms of interactions with both sides of the positively charged N atom.

scholarly journals Nucleophile sensitivity of Drosophila TRPA1 underlies light-induced feeding deterrence

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Eun Jo Du ◽  
Tae Jung Ahn ◽  
Xianlan Wen ◽  
Dae-Won Seo ◽  
Duk L Na ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radicals ◽  
Tissue Damage ◽  
Transient Receptor Potential ◽  
Uv Light ◽  
Receptor Potential ◽  
Solar Irradiation ◽  
Feeding Deterrence ◽  
Natural Sunlight ◽  
Transient Receptor

Solar irradiation including ultraviolet (UV) light causes tissue damage by generating reactive free radicals that can be electrophilic or nucleophilic due to unpaired electrons. Little is known about how free radicals induced by natural sunlight are rapidly detected and avoided by animals. We discover that Drosophila Transient Receptor Potential Ankyrin 1 (TRPA1), previously known only as an electrophile receptor, sensitively detects photochemically active sunlight through nucleophile sensitivity. Rapid light-dependent feeding deterrence in Drosophila was mediated only by the TRPA1(A) isoform, despite the TRPA1(A) and TRPA1(B) isoforms having similar electrophile sensitivities. Such isoform dependence re-emerges in the detection of structurally varied nucleophilic compounds and nucleophilicity-accompanying hydrogen peroxide (H2O2). Furthermore, these isoform-dependent mechanisms require a common set of TRPA1(A)-specific residues dispensable for electrophile detection. Collectively, TRPA1(A) rapidly responds to natural sunlight intensities through its nucleophile sensitivity as a receptor of photochemically generated radicals, leading to an acute light-induced behavioral shift in Drosophila.

Lipid peroxidation and the generation of free radicals, superoxide anion, and hydrogen peroxide in β-lapachone-treated Trypanosoma cruzi epimastigotes

1978 ◽  
Vol 186 (2) ◽  
pp. 292-297 ◽  
Author(s):  
Roberto Docampo ◽  
Fernando S. Cruz ◽  
Alberto Boveris ◽  
Ramiro P.A. Muniz ◽  
Darci M.S. Esquivel
Keyword(s):  
Hydrogen Peroxide ◽  
Lipid Peroxidation ◽  
Free Radicals ◽  
Trypanosoma Cruzi ◽  
Superoxide Anion

Decay Studies of Dmpo-Spin Adducts of Free Radicals Produced by Reactions of Metmyoglobin and Methemoglobin with Hydrogen Peroxide

1995 ◽  
Vol 22 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Young-Myeong Kim ◽  
Sang-Hyeon Jeong ◽  
Isao Yamazaki ◽  
Lawrence H. Piette ◽  
Sanghwa Han ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radicals

Melatonin: Lowering the High Price of Free Radicals

Physiology ◽  
2000 ◽  
Vol 15 (5) ◽  
pp. 246-250 ◽  
Author(s):  
Russel J. Reiter
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Free Radicals ◽  
Singlet Oxygen ◽  
High Price ◽  
Antioxidative Defense ◽  
Defense System ◽  
Toxic Species ◽  
Peroxynitrite Anion ◽  
Molecular Toxicity

The endogenous antioxidative defense system reduces molecular toxicity of oxygen and nitrogen-based reactive species. Melatonin is an efficient direct and indirect antioxidant. It detoxifies the highly reactive hydroxyl radical and neutralizes other toxic species, including singlet oxygen, hydrogen peroxide, nitric oxide, and peroxynitrite anion, and stimulates several antioxidative enzymes.

scholarly journals Reactive Intermediates in Oxygenation Reactions with Mononuclear Nonheme Iron Catalysts

2009 ◽  
Vol 48 (7) ◽  
pp. 1257-1260 ◽  
Author(s):  
Jihae Yoon ◽  
Samuel A. Wilson ◽  
Yu Kyeong Jang ◽  
Mi Sook Seo ◽  
Kasi Nehru ◽  
...  
Keyword(s):  
Reactive Intermediates ◽  
Nonheme Iron ◽  
Iron Catalysts
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