Nitros amines

Fischer-Hepp rearrangement The nitros-amines of aromatic secondary amines when treated with hydrochloric acid give nuclear substituted nitrosoamines. Among the benzene derivatives, if the para position is free the -NO group displaces the hydrogen atom there in naphthalene derivatives it enters the 1-position ... 

Nitro alcohols react with amines to form nitro amines. Such a reaction can be carried out with a wide variety of primary and secondary amines, both ahphatic and aromatic a basic catalyst is requited if aromatic amines are involved. The products of reactions between dihydric nitro alcohols and amines are nitrodiamines, many of which are good fungicides (qv). Dihydric nitro alcohols, primary amines, and formaldehyde react to yield nitrohexahydropyrimidines (4). Nitrohexahydropyrimidines can be reduced to the corresponding amines, some of which are good fungicides or bactericides, eg, hexetidine [141-94-6] (5-amino-l,3—bis(2-ethylhexyl)-5-methylhexahydropyrimidine). 

Although this reduction is more expensive than the Bnchamp reduction, it is used to manufacture aromatic amines which are too sensitive to be made by other methods. Such processes are used extensively where selectivity is required such as in the preparation of nitro amines from dinitro compounds, the reduction of nitrophenol and nitroanthraquinones, and the preparation of aminoazo compounds from the corresponding nitro derivatives. Amines are also formed under the conditions of the Zinin reduction from aromatic nitroso and azo compounds. 

N-Nitro-amine werden in der Regel durch Hydride nicht angegriffen (s. S. 365), Nitrone an der C=N-Doppelbindung hydriert (s.S. 373). Zur Reduktion von Furoxanen s.S. 378. 

The above scheme satisfies much of the metabolic data however, some of it is speculative, and it is certainly incomplete. The evidence for the formation of the a-hydroxylated intermediate is circumstantial. The acetate ester of a-hydroxylated dimethylnitrosamine has been prepared (12.13) and has been found to be a potent, directly acting carcinogen (14). Other esters of a variety of a-hydroxylated nitros-amines have also been prepared (15). While it has been shown that DMN acetate is hydrolyzed to hydroxymethylmethyl-nitrosamine by an esterase enzyme, it has been pointed out that these derivatives of the a-hydroxylated nitrosamines also dissociate to N-nitrosoimmonium ions (15 16). 

There is much evidence to suggest that carcinogenic N-nitros-amines are metabolised by an oxidative process to produce an alkylating agent (J f2) One potential metabolite is therefore the corresponding N-nitrosamide resulting from 2-electron oxidation at the oc-carbon atom, and, indeed, such compounds appear to induce tumours at the site of application without metabolic activation (3) It follows that the chemical properties of N-nitrosamides are relevant to the etiology of cancer ... 

N-Nitrosamides are much less stable than the parent N-nitros-amines and they can decompose by either thermal, photolytic or acid and base (nucleophilic) catalysed pathways Thermal decomposition has attracted much attention as a clean method of deamin-... 

Gaseous nitrate" is total amount of species converted to NO by the molybdenum catalyst of a commercial NO-NOx analyzer ( ). This includes N02f MONO and organic nitrates, and possibly nitros-amines and nitramines. 

The mechanism of NPYR formation has been studied by Coleman (37) and Bharucha et al. ( ). Coleman (37) reported that the requirement for a high temperature, the inhibitory effects of water and antioxidants, and the catalytic effect of a lipid hydroperoxide are consistent with the involvement of a free radical in the formation of NPYR. Similarly, Bharucha et al. (29) suggested that, since both NPYR and NDMA increase substantially towards the end of the frying process, N-nitros-amine formation during frying of bacon occurs essentially, if not entirely, in the fat phase after the bulk of the water is removed and therefore by a radical rather than an ionic mechanism. These authors speculated that, during the frying of... 

Smoking. The effects of smoking on the formation of N-nitros-amines in bacon has been investigated recently by Bharucha et al. ( ). They reported that unsmoked bacon samples generally tended to contain more N-nitrosamines, presumably because of their higher nitrite content at the time of frying. Sink and Hsu (55) showed a lowering of residual nitrite in a liquid smoke dip process for frankfurters when the pH also was lowered. The effects of smoke seem to be a combination of pH decrease and direct C-nitrosation of phenolic compounds to lower the residual nitrite in the product (56). This is an area which requires further study since certain C-nitrosophenols have been shown to catalytically transnitrosate amines in model systems (57). 

Research on the formation of NDMA in beer has centered on three possible sources of amine precursors (74). N-Nitros-amine formation from amines such as hordenine, famine and methyltyramine which are formed endogenously in the germination of barley has been discussed elsewhere in this symposium (75). The Brewers Association of Canada (74) investigated the... 

Nonvolatile Nitrosamines In Tobacco Smoke. Although there are more than 10 million exsmokers in the U.S.A., 53 million adults continue to smoke cigarettes and an additional 10 million still smoke cigars or pipes (39). The cigarette smokers are exposed to about 10 ng of volatile nitrosamines, 20-40 ng of NDELA and, most importantly, to 1-10 pg of tobacco specific N-nitros-amines with each cigarette smoked (Table IV). Similar quantities of the TSNA are found in sidestream smoke. The quantities of TSNA in the smoke are dependent on nitrate, nitrite, tobacco alkaloids and on NNN, NNK and NAT in the tobacco itself (31)>... 

N-nitro amines, RNHN02, decompose to alcohols and nitrous oxide in strong acid media. Rate constants obtained for R = methyl in sulfuric acid222 224 are illustrated as excess acidity plots in Fig. 12.119 This shows multiple curvature, but analysis according to equation (59) shows that one water molecule is involved in the reaction up to about 80 wt% H2S04, and one bisulfate ion above this point, see Fig. 13. The proposed mechanism is shown in Scheme 2. 19... 

The kinetics of base hydrolysis of several complexes of the type [Co(NH3)3L3] have been examined in order to see whether the mechanism for these uncharged complexes is the same as that operating for base hydrolysis of the standard cationic complexes (75). A comparison of kinetic parameters - a small selection is given in Table II (76,77) - suggests that all cobalt(III)-nitro-amine complexes, charged and uncharged, undergo base hydrolysis by the SnICB (Dch) mechanism. 

Kinetic Parameters for Base Hydrolysis of Selected Cobalt(III)-nitro-amine... 

Dimethylamine forms, first, dimethylammonium nitrite. When the temperature is raised, intramolecular change involving the double bond of the nitrous acid takes place, water is eliminated, and acylation, i.e. formation of nitro amine, occurs. 

The dinitrocubane 362 was prepared from the corresponding diisocyanate in this way404. In contrast, treatment of isocyanates with nitronium tetrafluoroborate and nitric acid yields A,A-dinitroalkylamines, e.g. BuN(NC>2)2 from butyl isocyanate405. N-Nitrosodialkylamines are oxidized to the corresponding nitro amines by hydrogen peroxide in aqueous acetic acid, e.g. equation 123406. 

Three derivatives of 3-aminodibenzothiophene, 110a, 110b, and 110c, have been nitrated, and in each case substitution occurred in the 4-position. Hydrolysis of the products yielded 3-amino-4-nitro-dibenzothiophene, which was different from the previous two nitro-amines and which formed an imidazole different from both 104 and 109. Deamination of this nitroamine via diazotization gave a small amount of 4-nitrodibenzothiophene. An alternative synthesis of the 4-nitro compound is described later. The spectroscopic techniques used above by Sawicki were later extended to determine the positions of substitution in dibenzoselenophene, in this case by comparison with the above-established derivatives of dibenzothiophene. - ... 

Nitroamine oxide reduced selectively to nitro amine. 

---