Nitroamines, formation

Cooney. R. V., Ross, P.D., Bartolini, G.L., and Ramseyer, J. IV-Nitrosamine and IV-nitroamine formation factors influencing the aqueous reachons of nitrogen dioxide with morpholine. Environ. Sci. Technol, 21 (l) 77-83,1987. 

The introduction of iV -alkyl groups into aniline so as to prevent nitroamine formation results in rather complex mixtures of products with HNO3, at different concentrations and media As an... 

The two reactions, hydration and dehydration, or, more exactly, the formation of nitrous oxide and of nitric acid, are more or less general reactions of the substituted nitroamines. The extent to which one or the other occurs depends largely upon the groups which are present in the molecule. Thus, tetryl on treatment with concentrated sulfuric acid forms nitric acid, and it gives up one and only one of its nitro groups in the nitrometer, but the reaction is not known by which nitrous oxide is eliminated from it. Methylnitramine, on the other hand, gives nitrous oxide readily enough but shows very little tendency to produce nitric acid. 

These quinone derivatives, by further reduction, can produce only arnidophenols. If the quinone formation is prevented from taking place, for instance by esterifying the hydroxyl-group, the normal reaction to azoxy-bodies occurs, o- and p-Nitroanisol pass smoothly into azoxy- or azo-derivatives. The acylizing of the amido-group in the case of o- and p-nitroamines hinders likewise the quinone, and. therewith the amine, formation. The azoxy-body is smoothly formed, thus ... 

Challis BC, Li BF. 1982. Formation of n-nitroamines by photolysis. IARC Sci Publ 41 31-40. 

The conditions required for the isolation of such nitroamines have been described [204], In concentrated sulfuric acid they readily rearrange to 2-amino-5-nitrothiazoles. The isomerization rate depends strongly on the sulfuric acid concentration [204], Thus, the formation of 2-amino-5-nitrothiazoles may be the result both of direct electrophilic substitution in the thiazole ring and of the aforementioned rearrangement. 

The same principle can be used to explain the formation of amides of nitric and nitrous acids (or the formation of nitroamines and diazotization). If A = NO2, then... 

Mechanistically, their formation can be explained either by rearrangement of the intermediate A -nitroamines in acidic medium or by the direct nitration of 5a. Alternatively, BTDOs are prepared from anilines 39 by diazotization and treatment of diazonium salts 41 with t 7-chloroperbenzoic acid (MCPBA). A third methodology consists of a P4O10- or PCls-promoted ring closure of iV-nitroanilines 40, achieved in the case of 5a and 5h <2000RCB482>. 

Nitration of 2-amino-3-methyl-IbP proceeds at room temperature, but it is limited to the formation of a nitroamine. The attempt to rearrange this compound into a C-nitro derivative by heating with concentrated H2SO4 failed, as with 2- and 4-nitroaminopyridines. 

The mode of reaction of NO2 BF4 with substituted methylenedianiines depends on the nature of the substituents [123,124], Alkanesulfonyl, arenesulfonyl, or methoxycarbonyl derivatives undergo nitrolysis at the C—N bond with formation of substituted nitroamines. This reaction pathway is favored by the formation of the carbonium-immonium ion stabilized by the amino nitrogen. 

Figure 8.2 Role of Enterobacteriaceae in the formation of nitroamines in fermenting wort. Originally adapted from Priest (2006).

The proportions of isomers in each reaction, point to two different types of orientation, although formation of nitroamines also takes place in the reaction of HNO3 with aniline derivatives in acid... 

The aza Henry reaction of N-phosphinyl aldimines with nitroalkanes was promoted by (9) to give P-nitroamines with good enantioselectivity (Scheme 2.37) [88]. The thiourea activated the nitro group, thereby facilitating the formation of the nucleophilic nitronate anion. They subsequently found that the use of N-Boc imine improved the enantioselectivity with reversal of the facial selectivity (Scheme 2.38) [89]. 

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