Amine nitrosoalkane

Hindered di-t-alkylamines RNHBu1 (R = t-Bu, t-octyl or 1-adamantyl) have been synthesized from t-alkylamines as follows. Reaction with peracetic acid gave the nitrosoalkanes RNO, which were treated with t-butyl radicals, generated from t-butylhydrazine and lead(IV) oxide, to yield t-butyloxyhydroxylamines. Reduction with sodium naphthalide in THF gave the products (equation 12). The di-t-alkyl-amines are inert to methyl iodide and dimethyl sulphate but can be alkylated by methyl fluorosulphonate42. 

The bimolecular reduction of aliphatic nitroso compounds is complex and somewhat unreliable. With careful control of reaction conditions, a-nitroso ketones (in dimeric form) may be reduced with stannous chloride in an acidic medium at room temperature to the azoxy compounds, while dimeric a-nitroso acid derivatives may be reduced at about 50°C [10, 35, 36]. Nitrosoalkanes, on the other hand, are decomposed at room temperature to alcohols and nitrogen, and are reduced to amines at 50°-60°C. It has been postulated that only the dimeric nitroso compounds can be reduced to azoxy compounds and, in fact, that the dimer has a covalent nitrogen-nitrogen bond. Equations (31)—(34) summarize these data [10]. 

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). 

MCPBA has been regarded as the reagent of choice for the conversion of primary aliphatic amines into the corresponding nitro compounds. The peroxy acid must be used in excess to minimize formation of dimers of the intermediate nitroso compounds, llie yield of nitroalkane is also increased if the reaction is carried out at elevated temperature, since this favors the monomeric rather than the dimeric foim of the intermediate nitrosoalkane and allows it to be oxidized further. For example, cyclohexylamine gave the dimer of nitrosocyclohexane (43%) when oxidized by MCPBA at 23 C, but at 83 C (in boiling 1,2-di-chloroethane) the only product was nitrocyclohexane (86%). 

For 1 1 adducts of nitroso ligands, side-on, 0-, and A -ligated modes are possible (Figure 4.19). No 0-nitroso complexes have been definitively characterized by diffraction methods. For hemoglobin the A -nitroso mode is likely, since this is the mode found for the nitrosoalkane in Fe(TPP)(amine)(RNO). ... 

The probable reaction course to the nitroalkane (XI), after the formation of the amine-ozone adduct (Reaction 1), is shown by Reactions 7 to 9 and summed up in Reaction 10. A primary amine oxide would not be expected to be stable and should rearrange to the hydroxylamine (IX, Reaction 7). A similar set of reactions (Reaction 8) should result in the nitrosoalkane (X), which should then be converted to the nitroalkane (XI) as shown in Reaction 9. Evidence for this series of reactions was the observation of the blue color of the nitrosoalkane (X) throughout the ozonation and the demonstration, in separate experiments, that the hydroxylamine (IX) reacts with two mole equivalents of ozone and the nitrosoalkane (X) with one mole equivalent of ozone, each to give the nitroalkane (XI). 

Nitrogen Compounds. The aqueous Oxone-acetone combination has been developed for the transformation of certain anilines to the corresponding nitrobenzene derivatives, as exemplified in eq 15. This process involves sequential oxidation steps proceeding by way of an intermediate nitroso compound. In the case of primary aliphatic amines, other reactions of the nitrosoalkane species compete with the second oxidation step (for example, dimerization and tautomerization to the isomeric oxime), thereby limiting the synthetic generality of these oxidations. An overwhelming excess of aqueous Oxone has been used to convert cyclohexylamine to nitrocyclohexane (eq 16)P... 

Microperoxidase 8 is a heme octapeptide, obtained by enzymatic hydrolysis of heart Cytochrome c, in which a histidine is axially co-ordinated to the heme iron, and acts as a fifth ligand. It exhibits two kinds of activities a peroxidase-like activity and a cytochrome P45o-like activity. Ricoux et al. (2000) have shown that microperoxidase 8 is not only able to oxidise various aliphatic and aromatic hydroxyl-amines with the formation of microperoxidase 8-Fe(II)-nitrosoalkane or -arene complexes absorbing around 414 nm, but also that these complexes can be obtained by reduction of nitroalkanes. 

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