Reactions of Nitroso Compounds

Trifluoroethanol has been shown to promote the addition of nitrenes, generated by the reaction of nitroso-compounds with phosphites, to aromatic hydrocarbons, e.g. (57), (58), and (59) are formed from the reaction... 

Among all the reactions of nitroso compounds the most widely studied has been homolysis to generate NO [189]. However, other reactions are known for example, N-nitrosoaziridenes lose N2O to form alkenes in a cheletropic fragmentation [190]. In contrast, N-nitrosimines (Scheme 3.21) spontaneously lose nitrogen rather than... 

Reaction of nitroso compounds with active methylene groups to give imines [46a, b]. 

Allyl amines can also be formed in an oxidative environment. Nicholas et al. have shown that instead of phenyl hydroxylamine as the nitrogen donor, it is possible using f-BuOOH as the terminal oxidant and the molybdenum catalyst described above [65]. The procedure is analogues to the in situ hetero-Diels-Alder reaction of nitroso compounds developed earlier by others [66]. 

During the nitration of aromatic compounds a certain amount of diazo compounds as by-products can also be formed. This for the first time was described by Weselsky as early as in 1875 [84] in the case of nitration of phenols with nitrogen dioxide and of nitration of aromatic hydrocarbons by Titov and Baryshnikova [85], Titov [39] explained the reaction as the result of reaction of nitroso compounds with NO ... 

The reaction of nitroso compounds with typical metal enolates, the nitroso aldol reaction, occurs in high yields to generate a-hydroxyamino carbonyl compounds. Exclusive iV-selectivity >99 1 is observed to give hydoroxyamino ketone in the reaction with tin enolates (Equation (70)).2... 

Aromatic and aliphatic primary amines can be oxidized to the corresponding nitro compounds by peroxy acids and by a number of other reagents. The peroxy acid oxidations probably go by way of intermediate hydroxylamines and nitroso compounds (Scheme 2). Various side reactions can therefore take place, the nature of which depends upon the structure of the starting amine and the reaction conditions. For example, aromatic amines can give azoxy compounds by reaction of nitroso compounds with hy-droxylamine intermediates aliphatic amines can give nitroso dimers or oximes formed by acid-catalyz rearrangement of the intermediate nitrosoalkanes (Scheme 3). 

Triazinamines 13 react with formaldehyde and hydrogen cyanide to yield A-(cyano-methyl)-1, 2,4-triazinamines 12.351 Reaction of nitroso compounds with 1,2,4-triazinamines affords azo compounds 14,352 which are also obtained by oxidation of hydrazino-1,2,4-triazi-nes 15 with iron(lll) chloride.355... 

N-Allylhydroxylamines can be prepared from nitrone hydrochlorides, which are produced by the reaction of nitroso compounds with alkenes, in an ene-type mechanism (Scheme 188). Analogues of potent dopaminomimetic ergot derivatives have been prepared, in which of a (5R,8S,10R)-6-allylergoline N -oxide was converted into a substituted hydroxylamine function. The key step is a Meisenheimer [3,2] sigmatropic rearrangement of the N6-oxide (Scheme 189). 413... 

Diets-Alder reaction of nitroso compounds [84JOC4741, 86JACS1306, 78TL4767, 80JACS3632, 85JACS5534]... 

Ruthenium and iridium catalysts have also been shown to promote the reaction of nitroso compounds with simple ene substrates. In this example, hydrogen peroxide acted as the oxidant to convert the hydroxylamine into the nitroso compound in situ. Ru- or Ir-catalyzed reaction with 2-Me-2-butene (85) then provides a mixture of regioisomers. The metal utilized greatly influences the ratio of products Ru was proven to be more twix selective giving an 8 1 ratio of 156 and 157. ... 

To obtain spin-labelled polymers, various nitroso compounds are widely used. The wide set of reactions represents a variety of methods of polymer modification by these compounds. In most cases, ARs can be generated by reactions of nitroso compounds with metalorganic reactants ... 

The nucleophilic attack on the nitrogen atom of a nitroso group is the limiting stage of condensation reactions of nitroso compounds with amines, methylene-active, and organomagnesium compounds, of Ehrlich-Sachs, Fischer-Hepp, Burton, and other reaction [161,162]. 

The free-radical reactions in solid polymers in the presence of NO are of particular significance for the preparation of spin-labelled polymers. This method has become particularly important for chemically inert, rigid and insoluble polymers, for instance, polytetrafluoroethylene (PTFE), because of the difficult problem of introducing spin labels by chemical reactions of nitroso compounds, nitrons or nitroxyl biradicals [31], Oriented PTFE films y-irradiated at room temperature in air after prolonged NO exposure contain nitroxyl radicals whose ESR spectra are displayed in Figure 3 [32],... 

Lypkalo IM, Ioffe SL, Strelenko Y, Tartakovsky VA (1996) A novel general method for the synthesis of nitrones by reaction of nitroso compounds with anions of aliphatic nitro compounds. Russ Chem Bull 45(4) 856-862. doi 10.1007/BE01431312... 

This reaction of nitroso compounds, which in some cases occurs very easily due to either heat or light, may be used to identify bands associated with the nitroso group by observing their disappearance from the spectrum. This conversion can easily be detected since nitroso compounds are highly coloured and oximes are not. 

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