Nitroso compounds oxidation

Complexes of the lanthanides with amine oxides, nitroso compounds, and nitroxide radicals fall under this category. However, only the complexes with the amine oxides have received wide attention. Four comprehensive reviews have appeared on the complexes of amine oxides with various metal ions 142-145). Only a few complexes of the lanthanides have been quoted in these reviews. 

Alternatively, the nitroxide radicals (and the related alkoxyamines) can be formed in the polymerizing mixture by the reaction of conventional radical initiators with nitric oxide, nitroso compounds, or nitrones. Formation of nitroxides and alkoxyamines from nitric oxide, nitroso compounds and nitrones is exemplified in Scheme 4.10 for compounds 171 1482 18-19. ... 

Reactions with Organic Compounds. Tetrafluoroethylene and OF2 react spontaneously to form C2F and COF2. Ethylene and OF2 may react explosively, but under controlled conditions monofluoroethane and 1,2-difluoroethane can be recovered (33). Benzene is oxidized to quinone and hydroquinone by OF2. Methanol and ethanol are oxidized at room temperature (4). Organic amines are extensively degraded by OF2 at room temperature, but primary aHphatic amines in a fluorocarbon solvent at —42°C are smoothly oxidized to the corresponding nitroso compounds (34). 

The effects of uv radiation on V/-nitroso compounds depend on the pH and the medium. Under neutral conditions and ia the absence of radical scavengers, these compounds often appear chemically stable, although the E—Z equiUbrium, with respect to rotation around the N—N bond, can be affected (70). This apparent stabiUty is due to rapid recombination of aminyl radicals and nitric oxide [10102-43-9] formed duting photolysis. In the presence of radical scavengers nitrosamines decay rapidly (71). At lower pH, a variety of photoproducts are formed, including compounds attributed to photoelimination, photoreduction, and photo-oxidation (69). Low concentrations of most nitrosamines, even at neutral pH, can be eliminated by prolonged kradiation at 366 nm. This technique is used ki the identification of /V-nitrosamines that are present ki low concentrations ki complex mixtures (72). 

Nitroso compounds are formed selectively via the oxidation of a primary aromatic amine with Caro s acid [7722-86-3] (H2SO ) or Oxone (Du Pont trademark) monopersulfate compound (2KHSO KHSO K SO aniline black [13007-86-8] is obtained if the oxidation is carried out with salts of persulfiiric acid (31). Oxidation of aromatic amines to nitro compounds can be carried out with peroxytrifluoroacetic acid (32). Hydrogen peroxide with acetonitrile converts aniline in a methanol solution to azoxybenzene [495-48-7] (33), perborate in glacial acetic acid yields azobenzene [103-33-3] (34). 

With a peroxyacid, the reagent used in their preparation, oxaziridines further react to yield aliphatic nitroso compounds. An electrophilic attack to ring nitrogen is plausible, leading to an intermediate oxaziridine N-oxide (81), which immediately decomposes to a nitroso compound and an aldehyde (57JA6522). 

Aliphatic nitroso compounds are obtained either by hypobromite oxidation of alkylhy-droxylamines made by oxaziridine hydrolysis, or directly from oxaziridines by action of a second mole of peracid (Section 5.08.3.1.3). 

N-Metal Derivatives N-Nitroso Compounds N-Nitro Compounds Azo Compounds Arenediazoates Arenediazo aryl sulphides Bis-arenediazo oxides Bis-arenediazo sulphides Trizazenes (R=H, -CN, -OH, -NO)... 

Nitroso compounds are oxidized to nitro compounds by hydrogen peroxide and dinitragen tetroxide [S2] (equation 74)... 

Oxidative Conversion of Oxaziranes into Nitroso Compounds... 

Oxaziranes are rapidly decomposed by the further action of peracids. As shpwn by Emmons and Krimm the oxazirane is converted into a carbonyl compound and a nitroso compound dimer. The reaction can be formulated via an oxazirane A -oxide intermediate [Eq. (30)]. 

Catalytic cleavage of the nitrogen-oxygen bond occurs very frequently as in reduction of nitro compounds, oximes, and various heterocyclics these reactions are discussed in separate chapters. Considered here are N-oxides, hydroxylamincs, and N- and C-nitroso compounds. 

The intramolecular /zetero-Diels-Alder reactions of 4-O-protected acyl-nitroso compounds 81, generated in situ from hydroxamic acids 80 by periodate oxidation, were investigated under various conditions in order to obtain the best endo/exo ratio of adducts 82 and 83 [65h] (Table 4.15). The endo adducts are key intermediates for the synthesis of optically active swainsonine [66a] and pumiliotoxin [66b]. The use of CDs in aqueous medium improves the reaction yield and selectivity with respect to organic solvents. 

With some alkenes, the initial p-halo nitroso compound is oxidized by the NOCl to a P-halo nitro compound. Many functional groups can be present without interference (e.g., COOH, COOR, CN, OR). The mechanism in most cases is probably simple electrophilic addition, and the addition is usually anti, though syn addition has been reported in some cases. Markovnikov s rule is followed, the positive NO going to the carbon that has more hydrogens. 

Hydrazones of the form ArCH=NNH2 react with HgO in solvents such as diglyme or ethanol to give nitriles (ArCN). Aromatic hydroxylamines (Ar—NH-—OH) are easily oxidized to nitroso compounds (Ar—N=0), most commonly by acid dichromate. ... 

Oxidation of Primary Amines, Oximes, Azides, Isocyanates, or Nitroso Compounds to Nitro Compounds... 

Dimethyl dioxirane in wet acetone oxidizes isocyanates to nitro compounds (RNCO —> RN02). Oximes can be oxidized to nitro compounds with peroxytri-fluoroacetic acid, or Oxone ," sodiumperborate," among other ways. " Primary and secondary alkyl azides have been converted to nitro compounds by treatment with PhjP followed by ozone. Aromatic nitroso compounds are easily oxidized to nitro compounds by many oxidizing agents. ... 

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