Nitroso Anilines

Ndrasa-c[Pg.341]

Fathead minnow, Pimephales promelas, acute toxicity, nitrobenzenes, chloroanilines, alkylanilines, OSAR, sigma minus values, anilines, nitroso compounds, tautomerism, Michael acceptors, electrophiles. 

By condensing nitroso derivatives with primary amines. Nitrosobenzene and aniline, for example, readily give azobenzene. This method is seldom used... 

Secondary and tertiary amines are not generally prepared in the laboratory. On the technical scale methylaniline is prepared by heating a mixture of aniline hydrochloride (55 parts) and methyl alcohol (16 parts) at 120° in an autoclave. For dimethylaniline, aniline and methyl alcohol are mixed in the proportion of 80 78, 8 parts of concentrated sulphuric acid are added and the mixture heated in an autoclave at 230-235° and a pressure of 25-30 atmospheres. Ethyl- and diethyl-anihne are prepared similarly. One method of isolating pure methyl- or ethyl-aniline from the commercial product consists in converting it into the Y-nitroso derivative with nitrous acid, followed by reduction of the nitroso compound with tin and hydrochloric acid ... 

The diazonium salts 145 are another source of arylpalladium com-plexes[114]. They are the most reactive source of arylpalladium species and the reaction can be carried out at room temperature. In addition, they can be used for alkene insertion in the absence of a phosphine ligand using Pd2(dba)3 as a catalyst. This reaction consists of the indirect substitution reaction of an aromatic nitro group with an alkene. The use of diazonium salts is more convenient and synthetically useful than the use of aryl halides, because many aryl halides are prepared from diazonium salts. Diazotization of the aniline derivative 146 in aqueous solution and subsequent insertion of acrylate catalyzed by Pd(OAc)2 by the addition of MeOH are carried out as a one-pot reaction, affording the cinnamate 147 in good yield[115]. The A-nitroso-jV-arylacetamide 148 is prepared from acetanilides and used as another precursor of arylpalladium intermediate. It is more reactive than aryl iodides and bromides and reacts with alkenes at 40 °C without addition of a phosphine ligandfl 16]. 

Nitroso compounds are formed selectively via the oxidation of a primary aromatic amine with Caro s acid [7722-86-3] (H2SO ) or Oxone (Du Pont trademark) monopersulfate compound (2KHSO KHSO K SO aniline black [13007-86-8] is obtained if the oxidation is carried out with salts of persulfiiric acid (31). Oxidation of aromatic amines to nitro compounds can be carried out with peroxytrifluoroacetic acid (32). Hydrogen peroxide with acetonitrile converts aniline in a methanol solution to azoxybenzene [495-48-7] (33), perborate in glacial acetic acid yields azobenzene [103-33-3] (34). 

The N,]S -dialkyl-/)-PDAs are manufactured by reductively alkylating -PDA with ketones. Alternatively, these compounds can be prepared from the ketone and -lutroaruline with catalytic hydrogenation. The /V-alkyl-/V-aryl- -PDAs are made by reductively alkylating -nitro-, -nitroso-, or /)-aminodipheny1 amine with ketones. The AijAT-dialkyl- PDAs are made by condensing various anilines with hydroquinone in the presence of an acid catalyst (see Amines-aromatic,phenylenediamines). 

Condensation of phenol [108-95-2] C H O, withy -nitroso-N,N-dimethyl-aniline [138-89-6] CgH QN20, in acetic acid (9). 

Nitiosobenzene, which shares the general character of nitroso-compoLinds in gnung rise to a gneen vapour or solution, is leadily reduced to phenylhydroxylamine and aniline. It condenses with ammo-compounds, yielding azo- or diazo-derivatives. 

Dinitro-N-nitroso-N-methylaniline (2,6-dinitrophenyl-N-methylnitrosamine), white needles, mp. 115—16° prepd by the action of Na nitrite in acet ac on 2,6-dinitro-N-methyl-aniline (Refs 3 6)... 

In another investigation81,185, the rates of formation of para-nitroso-N-methyl-aniline from N-nitroso-N-methylaniline in hydrochloric acid solution at 31 °C were measured by noting the appearance of the absorption at 340 mn due to the protonated from of the para-nitroso-N-methylaniline. A typical run is shown in Fig. 3. The decreasing absorption at about 260 m/i represents the disappearance... 

Benzochinon-bis-oxim wird in alkalischem Medium (alkoholische Natronlauge) bei -1,4 V zum schwer zuganglichen x-Nitroso-anilin (8,5% d.Th.)6, in saurem Medium (Schwefelsaure) zu 1,2-Diamino-benzol (Hauptprodukt) neben 2,3-Diamino-phenazin reduziert8,9 ... 

The use of a PTC, tetramethylammonium hydroxide, to carry out the coupling under aeration of nitrobenzene and aniline to give nitroso diphenylamine (which on catalytic reduction with H2 gives 4-aminodiphenylamine, required in the rubber industry) may be cited as a green chemistry route compared to the established process based on p-nitrochlorobenzene and aniline where Cl is wasted (Bashkin et al. 1999). 

Tricyclic antihistamines as a rule carry aliphatic nitrogen as a substituent on a side chain attached to the central ring the side chain nitrogen may be part of a heteroaromatic ring. Conjugate addition of p-chloroaniline (49) to the substituted vinylpyridine 50 gives the alkylated aniline 51. Treatment of that intermediate with nitrous acid leads to N-nitroso intermediate 52 which is then reduced to the hydrazine (53). Reaction of 53 with N-methyl-4-piperidone... 

N-Nitroso compounds occur in many operations in the rubber industry. Some nitrosamines (nitrosodiphenylamine, N-N-dinitrosopentamethylenetetramine, polymerized N-nitroso 2,2,4-trimethyl-l,2-dihydroquinoline and N-methyl-N-4-dinitroso aniline) are used as organic accelerators and antioxidants in the production of rubber and often the products are found to be contaminated with such compounds [19]. 

Bindschedler s Green (6.204) can be made by condensing p-nitroso-N,N-dimethylaniline with N,N- dimethyl aniline. A similar condensation with 2-naphthol gives Meldola s Blue (6.209 Cl Basic Blue 6), the first oxazine dye, discovered in 1879. The symmetrical Cl Basic Blue 3 (6.210) is of more commercial significance. It is synthesised by nitrosation of N,N-diethybrn-anisidine followed by condensation with N,N-diethybm-aminophenol, and is used for dyeing acrylic fibres. This dye is now classified by ETAD as toxic [73]. 

Hydrogen telluride reduces hydroxylamines to anilines, and nitroso, azo and azoxy compounds to the corresponding hydrazo compounds. - ... 

Aromatic amines (anilines) may become activated in vivo to form reactive amines. These are nucleophiles and may attack DNA, forming covalent modifications. Aromatic nitro compounds can be metabolised to also form reactive amines. A-nitroso compounds result in the alkylation of oxygen sites in DNA bases (0-6 in guanine and 0-4 in thymidine) [8,10]. 

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