A’-nitroso compounds and

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). 

Azoxy compounds can be obtained from nitro compounds with certain reducing agents, notably sodium arsenite, sodium ethoxide, NaTeH, NaBH4—PhTeTePh, and glucose. The most probable mechanism with most reagents is that one molecule of nitro compound is reduced to a nitroso compound and another to a hydroxylamine 119-42), and these combine (12-51). The combination step is rapid compared to the reduction process. Nitroso compounds can be reduced to azoxy compounds with triethyl phosphite or triphenylphosphine or with an alkaline aqueous solution of an alcohol. ... 

The mechanism of oxynitration is generally accepted to involve the formation of phenyl mercuric nitrate which reacts with nitrogen oxides in the nitric acid to form a nitroso compound and then a diazonium salt the latter forms a phenol under the aqueous conditions which is then further nitrated. The use of more concentrated nitric acid favours a process of mercuration-nitration and suppresses the formation of phenols. ... 

The bimolecular reduction of nitro compounds is believed to involve reduction of some of the starting material to a nitroso compound and another portion to either a substituted hydroxylamine or an amine. These intermediates, in turn, condense to form the azo compound. The exact mechanism of the reaction requires critical study. On the one hand, reducing conditions are always on the alkaline side to prevent the benzidine rearrangement of an intermediate hydrazo compound under acidic conditions, yet it is difficult to visualize the formation of hydrazo compounds by the indicated condensation. As a practical matter, this method is of value only if symmetrically substituted azo compounds are desired. 

The reduction of aromatic nitro compounds is believed to proceed to an intermediate mixture of nitroso compounds and substituted hydroxylamines which are not isolated but condense to form an azoxy compound which, in turn, is reduced to an azo compound. Contributing evidence to substantiate this mechanism is that the reduction of a mixture of two aromatic nitro compounds leads to a mixture of azo compounds consistent with that predicted if each of the nitro compounds were reduced to a nitroso compound and a hydroxylamine and these, in turn, reacted with each other in all possible combinations. This observation also implies that the bimolecular reduction of nitro compounds is practical only from the preparative standpoint for the production of symmetrically substituted azo compounds. Spectrophotometric studies of the reaction kinetics of the reduction of variously substituted nitro compounds may, however, uncover reasonable procedures for the synthesis of unsymmetrical azo compounds. 

During experiments to trap a reaction product of a nitroso compound and isonitrile with an alkyl isocyanate, an additional way of formation of diaziridinimines was discovered. Besides some other heterocycles the five-membered ring compound 138 was formed, which yielded 133 by extrusion of carbon dioxide at 150°. ... 

A-Nitroso compounds and specifically the A-nitrosamines exhibit mutagenic, carcinogenic, and teratogenic activities. Around 300 A-nitroso compounds have been tested to detect their carcinogenicity, with this activity found in most of them. It is demonstrated that the nitrosamines develop a carcinogenic effect in a wide range of animal species like fishes, reptiles, birds, and mammals, including hve species of primates. " ... 

Hecht, S.S. and D. Hoffmann A-Nitroso compounds and tobacco-induced cancers in man in Relevance to human cancer of A-nitroso compounds, tobacco and mycotoxins, edited by I.K. O NeiU, J. Chen, and H. Bartsch LARC, Lyon, France, LARC Sci. Puhl. No. 105 (1991)54-61. 

Preussmann, R. Occurrence and exposure to A-nitroso compounds and precursors in A-Nitroso compounds Occurrence, biological effects and relevance to human cancer, edited by I.K. O Neill, R.C. von Borstel, C.T. Miller, J. Long, and H. Bartsch, LARC, Lyon, France, lARC Sci. Publ. No. 57 (1984) 3-15. 

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