Nitroso oxide reactions

Fig. 9.5. The reaction of organic nitrites with thiols (Reaction a), and a general mechanism for the release of nitric oxide from S-nitroso thiols (Reactions b and c) [31]...

Aliphatic primary amines are known to be oxidized by dimethyl dioxiranes to various products such as oximes, nitroso dimers, nitroalkanes, nitrones and oxazrridines under various conditions depending upon the oxidation reaction . In contrast, when secondary amines lacking a-hydrogens are allowed to react with Oxone and PTC in buffered acetone solution at 0 °C, nitroxides are obtained in good yields in a few minutes (equation 61) . 

Oxidation of azo compounds 9-36 Oxidation of amines 9-66 Reduction of nitro or nitroso compounds reaction between nitroso compounds and hydroxylamines... 

Inue et al. claimed the first report of the infrared detection of an aryl nitroso oxide, made from the reaction of 4-nitrophenylnitrene with molecular oxygen.70 The singlet nitroso diradical is formed from the triplet nitrene and oxygen at a temperature of 50 K in argon or xenon matrices. The reaction does not occur at 40 K. 

Benzo[c]cinnoline-5,6-dioxide is a colorless, high-melting (243°C), non-basic compound, sparingly soluble in organic solvents. There has been discussion of spectroscopic evidence as to whether it has a di-JV-oxide or a nitroso-dimer type structure, hut there has been little investigation of its chemistry and there appears to be no chemical evidence for its behaving as 2,2 -dinitrosobiphenyl i.e., it shows no nitroso group reactions. 

As opposed to secondary amines and amides, their primary analogs can be oxidized to nitroso metabolites (reaction 4-C), but further oxidation of the latter compoundsto nitro compounds does not seem to occur in vivo. In contrast, aromatic nitro compounds can be reduced to primary amines through reactions... 

The influence which the nitroso- and nitro-groups exert on the other substituents is especially shown in oxidation reactions, which here occur much more readily than in the case of compounds which have not... 

The transient nitroxide radicals derived from one-electron oxidation of HXs may decompose via several routes as described in Scheme 2 including dis-mutation (reaction 9) and oxidation (reaction 10) forming acyl nitroso, which yields HNO via hydrolysis (reaction 14) or its reaction with nucleophiles (53), homolysis of the C-N bond forming HNO (reaction 11), internal disproportionation forming NO (reaction 12), and hydrolysis forming H2NO (reaction 13), which via dismutation generates N2 (54,55). 

Reactions with Amines, Imines, Nitroso Oxide, and Protic Solvents... 

Photochemical reactions of nitroso oxides at low temperatures with stilbenes have been reported [35]. Several singlet nitroso oxides were generated by the thermal reaction of triplet nitrenes with triplet oxygen at 95 K in 2-methyltetrahydrofuran. After photolysis of the nitroso oxides at 77 K, the formation of intermediates was observed. From spectroscopic and kinetics data, the authors postulated the formation... 

A notable exception to the rule of thumb that the nitrosoarene compound is favored under oxidative conditions is the observation of arylhydroxylamine rather than nitrosoarene metabolite in microsomal oxidase studies of arylamine metabolism (43). In vitro studies of N-oxidation generally contain the biological reductant NADPH, which can, by a mechanism independent of cytochrome P-450 catalysis, reduce any nitroso product back to the hydroxylamine state. Our studies on CPX-catalyzed oxidation of arylamines by H2O2 did not require a reductant such as NADPH, and thus, may better reflect the actual enzymatic or equilibrium product of oxidative reactions, including microsomal oxidations. Microsomal oxidations in which substrates such as cumene hydroperoxide are used in place of O2/NADPH should yield the nitrosoarene rather than arylhydroxylamine metabolite. In the case of 4-chloroaniline, the nitroso metabolite rather than the hydroxylamine metabolite was produced however, the major product was the nitroaromatic compound, indicative of further oxidation (55). This raises the hypothetical question as to whether... 

Oxidative reactions of organonitrogen species that do not involve molecular oxygen are rather limited. The only case for which the evidence is at all convincing is the oxidation of arylhydroxylamines to arylnitroso species (Table 2). This reaction resembles the first half of the hydroxylamine oxidoreductase reaction found in nitrifying bacteria. The key difference is that the aryl nitroso compound is stable (although condensation with the arylhydroxy-lamine can occur to produce the azoxy compound, ArN(O)NAr), while the inorganic analog is nitroxyl, HNO, which if released from the enzyme would rapidly dimerize and dehydrate to form N2O. Consequently, HAO does not release the HNO or NO intermediate, but instead oxidizes it to nitrite before any substrate-derived species are released. 

Harder, T., Wessig, R, Bendig, J., and Stosser, R., Photochemical reactions of nitroso oxides at low temperatures the first experimental evidence for dioxaziridines,/. Am. Chem. Soc., 121,6580,1999. 

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). 

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