JV-Nitroso compounds

Typical primary amines which undergo such nitrosation are m-toluidine, p-xylidine, m-anisidine, 2-amino-4-methoxytoluene, 3-amino-4-methoxy-toluene, m-aminophenol, a-naphthylamine, l-naphthylamine-2-, -6-, -7-, and -8-monosulfonic acids, and l-naphthylamine-4-monosulfonic acid (which reacts with displacement of the sulfonic acid group). The secondary amines derived from these primary amines also can be nitrosated directly (i.e., without the intermediate formation of an JV-nitroso compound which needs to be subjected to the Fischer-Hepp rearrangement). The entering nitroso group appears to substitute exclusively in the para position. 

Treatment of the JV-nitrosocyanides (283)198 or the W-nitrosoguanyl-hydrazines (284)199 with hydrogen chloride yielded the 1,2,3,4-oxatriazolium chlorides (285, X = Cl), which with aqueous sodium bicarbonate gave the meso-ionic l,2,3,4-oxatriazol-5-imines (277, R2 = H).198 Nitrosation of these compounds (277, R2 = H) gave the interesting JV-nitroso compounds (277, R2 = NO), and acylation gave the JV-acyl derivatives (277, R2 = RCO).198... 

Oxazolidinones react with nitrous acid, the resulting jV-nitroso compounds being decomposed by alkali to yield a variety of products alkynes, aldehydes and vinyl ethers. These transformations are rationalized by postulating the intermediacy of transient alkenediazonium ions (Scheme 27) (79CB2120). 

In general, most types of C-nitroso compounds appear to be reactive heterodienophiles. On the other hand, JV-nitroso compounds and nitrosyl chloride do not usually undergo [4 + 2] cycloadditions.1 Much of the early work in this area can be found in the Hamer and Kresze reviews, which cover the literature through 1967.,a b This chapter will emphasize newer aspects of [4 + 2] cycloadditions involving nitroso dienophiles. 

Nitrates and nitrites can give rise to other effects. They are, for example, able to decompose carotene. Nitrates affect the activity of the thyroid gland, which plays an important role in the conversion of carotene to vitamin A. The interactions of nitrites with amines are, however, much more dangerous, since they result in the production of jV-nitroso compounds. Many of these compounds damage the liver and exhibit teratogenic and carcinogenic effects [5, 15]. 

G. Neurath and M. Duenger, JV-Nitroso compounds from tobacco alkaloids. Beitr. Tabakforsch. 3, 339 (1966) CA 67, 64605 (1967). 

Castegnaro, M., Michelon, J., Walker, E. A. Some detoxifications methods for nitrosamine contaminated wastes, in JV-Nitroso Compounds Occurrence and Biological Effects (lARC Scientific Publications No. 41), (eds.) Bartsch, H., O Neill, I. K., Castegnaro, M., Okada, M., p. 151, Lyon, International Agency for Research on Cancer, 1982... 

Once again, biological interest in JV-nitroso-compounds has stimulated new syntheses of JV-nitrosoamines " and N-nitrosoureas. ... 

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