Nitrosocarbazole

Despite the relative figures for chlorination of 9-acetylcarbazole, electrophilic substitution of 9-acylcarbazoles has been used preparatively to produce 2-nitro- and 2-acylcarbazoles. " 9-Nitrosocarbazole nitrates at C-3. 

Chloroformylcarbazole reacts with 2-alkylaminoethanols and -ethan-amines to give the corresponding urethanes and ureas, with hydrazine to give and with nitrous acid to give 9-nitrosocarbazole in good... 

Nitrosocarbazole condenses with 9-aminocarbazole to give the azo compound 122, heating of which produces dimers in a ratio similar to that observed by oxidation of carbazole (see Section II,A,2) it was therefore believed to involve the carbazol-9-yl radical. 3-Nitro-9-nitrosocarbazole was shown to serve as a nitrosating agent for A-methylaniline it converted aziridine to ethene and nitrous oxide. ... 

Carbazoles normally react with electrophiles to yield the 3-monosubstituted and 3,6-disubstituted derivatives. Further reaction may occur at the 1- and the 8-positions. There is evidence that the initial reaction occurs at the 9-position. Thus, nitrosation of carbazole with sodium nitrite in acetic acid yields 9-nitrosocarbazole which, when treated with nitric acid, is converted into 3-nitrocarbazole (09CB3797) and 3,6-dinitrocarbazoIe (46USP2392067). Direct nitration of carbazole with nitric acid (02GEP128853) or with ethyl nitrate also yields the 3-nitro and 3,6-dinitro derivatives, together with 1,3,6,8-tetranitrocarbazole (27CB738). 

NDPHA, A-nitrosoatrazine, A-nitrosobenzylphenylamine, A-nitrosocarbazole, and A-nitroso-carbaryl in foods. In another study, Sen et al. (67) used a normal-phase system for the determination of NDBZA in cured pork products packaged in elastic rubber nettings (Fig. 4). As can be seen from the figure, appropriate solvent programming allowed the simultaneous determination of six nonpolar and three polar NOC. 

Nitration in acetic anhydride of 9-(p-tosyl)carbazole gave the 1-, 2-, and 3-isomers in 28, 19, and 53% yields, respectively, and for 9-acetyl- and 9-nitrosocarbazole these became, correspondingly, 10, 48, and 42%, and 24, 0, and 66% (84T1857). Nitration of carbazole itself under those conditions gave partial rate factors of/, = 32,100 /2 = 1100 and/3 = 77,600 (58JCS3079). 

A mixture of 50 g. (0.30 mole) of carbazole and 400 ml. of glacial acetic acid is heated to boiling and then cooled somewhat. Twenty-one grams (0.33 mole) of sodium nitrite is added to the stirred mixture in small portions at such a rate that the temperature of the mixture remains below the boiling point. There is next added, in the same manner as before, 83 ml. of a mixture of equal portions of acetic acid and nitric acid (sp. gr. 1.4). The precipitated crystalline material is filtered off and washed with ethanol. This material is 3-nitro-9-nitrosocarbazole, and it may be further purified by recrystallization from ethanol or ethyl acetate. 

Nitrosation Butyl nitrite. 3-Nitro-N-nitrosocarbazole. Nitrosyl chloride. 

Clark and Heimkamp found that deamination of meso- and d/-2,3-dimethyl-aziridine by reaction with 3-nitro-N-nitrosocarbazole is highly stereospeciflc. The >.vo-isomer (I) afforded c(. -butene-2 of 99.9% purity and the d/-isomer gave 99%... 

Deamination Aryidiazonium hexafluorophosphates. Aryldiazonium tetrahaloborates. Di-fluoroamine. Dinitrogen tetroxide (White). Hydroxylamine-O-sulfonic aeid. Hypophos-phorous acid. 3-Nitro-N-nitrosocarbazole. Nitrosyl chloride. Tetramethylurea. Debenzylation of benzoylamines Triethyloxonium fluoroborate. 

Nitration of carbazole gives an approximately 2 1 mixture of 3,6- and 1,6-dinitrocarbazole. It is synthetically advantageous to carry out the reaction on 9-nitrosocarbazole, with the nitroso group being lost during nitration (Scheme 115) <64JOC2474>. 

Treatment of an aziridine with nitrosyl chloride, S-nitro-TV-nitrosocarbazole or methyl nitrite leads to the formation of an alkene and nitrous oxide (equation 76) " an intermediate iV-nitroso derivative was isolated at low temperatures. The deamination of cis-and frflBJ-2,3-dimethylaziridine gave the corresponding ds- and fra J-2-butenes with complete stereospecificity in each case. The reaction was found to be first order with respect to the A nitroso intermediate and the transition state was suggested to involve simultaneous cleavage of both C—bonds. A similar decomposition... 

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