TV-Nitroso Compounds

The structure of the intermediate obtained from 3-phenyl-5-amino-l,2,4-thiadi-azole (Goerdeler and Deselaers, 1958) was elucidated by UV- and IR-spectroscopy. The results are consistent with the nitrosoamine structure 3.18. Its UV spectrum (Fig. 3.4) is very similar to that of the A-methyl-TV-nitroso compound 3.19, but different from that of the isomeric compound 3.20 with a methyl group in the 4-position (Goerdeler and Deselaers, 1958). The spectrum of this 4-methyl derivative is expected to be similar to that of the nitrosoamine structure 3.21, which is obviously not present, at least not in detectable tautomeric equilibrium concentration. 

N-nitrosomethlyphenylamine N-nitrosomethlyphenylamine TV-nitroso compounds nitric oxide nitrogen dioxide nitrate radical nitrite radical nitrogen trioxide... 

Mirvish, S.S., Issenberg, P., and Sornson, H.C. Air water and ether-water distribution of TV-nitroso compounds implications for laboratory safety, analytic methodology, and carcinogenicity for the rat esophagus, nose, and liver, J. Nat Cancer Instil, 56(6) 1125-1129, 1976. 

FIGURE 2-13. High performance liquid chromatographic separation of unknown TV-nitroso compounds. The colorimetric, photometric, and fluorometric detection responses are shown. Column /uBondapak C]8 3.9 mm ID x 30 cm. Mobile-phase composition was programmed from 20 to 80% acetonitrile in water (pH = 4, phosphoric acid) over 20 min, was held isocratic (constant mobile phase composition) for 22 min, and then was programmed from 80 to 100% acetonitrile in 1 min and held at 100% acetonitrile for 20 min. The flow rate was 1.0 mL/min. (Reprinted from reference 10 with permission. 

Anthranils are readily cleaved by nitrous acid, presumably by attack of water on TV-nitroso cations. The first product that can be observed is the nitrosohydroxylamino compound (232), which becomes reduced to the diazonium salt (233) (67AHC(8)277). 

AMJnsubstituted /3-lactams are nitrosated in acetic acid under nitrogen at 15 °C to give 7V-nitroso-/3-lactams (81), which can be reduced by zinc dust in acetic acid to afford the corresponding TV-amino compounds (82) (67G1719). 

Oxidation of the TV-aryl azanols under controlled conditions yields nitroso compounds. This reaction is not unlike the oxidation of alcohols to ketones (Section 15-6B) ... 

A nitrogen atom at X results in a variable downfield shift of the a-carbons, depending in its extent on what else is attached to the nitrogen. In piperidine 146 (X = NH) the a-carbon signal is shifted by about 20 ppm, to ca. S = 47.7, while in A-methylpiperidine 146 (X = Me) it appears at <5 = 56.7. Quaternization at nitrogen produces further effects similar to replacement of NH by A-alkyl, but simple protonation has only a small effect. A-Acylpiperidines show two distinct a-carbon signals, because of restricted rotation about the amide bond. The chemical shift separation is about 6 ppm, and the mean shift is close to that of the unsubstituted amine 146 (X = NH). The nitroso compound 146 (X = N-NO) is similar, but the shift separation of the two a-carbons is somewhat greater (ca. 12 ppm). The (3- and y-carbon atoms of piperidines, TV-acylpiperidines, and piperidinium salts are all upheld of the cyclohexane resonance by 0-7 ppm. 

See other ENDOTHERMIC COMPOUNDS, TV-HALOGEN COMPOUNDS, NITROSO COMPOUNDS, OXIDANTS... 

In this Section only those hydrazine syntheses are discussed that occur with formation of an N-N bond (TV-amination). For syntheses of substituted hydrazines by reduction of hydrazones, azines, iV-nitroso compounds, and diazonium salts the Sections relevant thereto should be consulted. 

Research into the mechanism of diazotization was based on Bamberger s supposition (1894 b) that the reaction corresponds to the formation of A-nitroso-A-alkyl-arylamines. The TV-nitrosation of secondary amines finishes at the nitrosoamine stage (because protolysis is not possible), but primary nitrosoamines are quickly transformed into diazo compounds in a moderately to strongly acidic medium. The process probably takes place by a prototropic rearrangement to the diazohydroxide, which is then attacked by a hydroxonium ion to yield the diazonium salt (Scheme 3-1 see also Sec. 3.4). 

TNT, 1,3 DNB, 1,3,5-TNB, some nitrocresol isomers, and 3,5-dinitroani-line. Several unexpected compounds were also identified, including A -nitroso-morpholine, TV morpholinoacetonitrile and nitrobenzonitrile isomers. The morpholine derivatives are not directly related to the nitration of toluene, and are possibly the result of the use of morpholine as an algaecide in water-cooling devices at munitions facilities. The major component in the wastewater was 1,3-DNB. Its formation is attributed to oxidation followed by decarboxylation of the methyl group in 2,4-DNT rather than to direct nitration of benzene. 

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