Aniline N-oxidation

Pyridin-, Chinolin- und N,N-Dimethyl-anilin-N-oxid werden elektrolytisch an Queck-silber in Methanol/Tetramethylammoniumchlorid zu Pyridin (81% d.Th.), Chinolin (78% d.Th.) bzw. N,N-Dimethyl-anilin (78% d.Th.) (galvanostat. bei 5 A/65°C) redu-ziert1. Analog verhalten sich 2- und 4-Methyl-pyridin-N-oxide (2-Methyl-pyridin 96% 4-Meihyl-pyridin 80% d.Th.)1. 

The cycloadditions of nitrones to alkylidenecyclopropanes are, by far, the most studied reactions of this class. The first example reported in the literature refers to the cycloaddition of AF-(phenylaminooxoethylidene)aniline N-oxide (249) to 2,2-dimethylmethylenecyclopropane (250). The authors report about the formation of a single 5-spirocyclopropane fused regioisomer 251 (Scheme 41) [63]. 

Roberts KM, Jones JP (2010) Anilinic N-oxides support cytochrome P450-mediated N-dealkyl-ation through hydrogen-atom transfer. Chem Eur J 16 8096-8107... 

In 2009, Zhang and coworkers described an efficient Au-catalyzed one-pot synthesis of seven-membered AT-heterocycles tetrahydrobenz[ ]azepin-4-ones 85 from aniline substrates with tethered terminal alkynes 84. Compound 85 were efficiently constructed by Au-catalyzed intramolecular cyclization of the tertiary aniline N-oxides in situ formed by oxidation of the corresponding aniline substrates with wj-CPBA (Scheme 12.41) [44]. 

Methyl violet [8004-87-3] Cl Basic Violet 1 (17), is made by the air oxidation of dimethyl aniline in the presence of salt, phenol, and a copper sulfate catalyst. Initially, some of the dimethyl aniline is oxidized to formaldehyde and /V-methyl aniline under those conditions. The formaldehyde then reacts with dimethyl aniline to produce N,N,]S7,1S7-tetramethyldiaminodiphenylmethane, which is oxidized to Michler s hydrol [119-58-4]. The hydrol condenses with... 

Phenazine mono-N-oxides have also been prepared from nitrobenzene derivatives. Condensation of nitrobenzene with aniline using dry NaOH at 120-130 °C results in modest yields of phenazine 5-oxide, although the precise mechanism of this reaction is not well understood (57HC(ll)l) with unsymmetrical substrates it is not possible to predict which of the isomeric fV-oxides will be produced. Nitrosobenzene derivatives also function as a source of phenazine mono-fV-oxides thus, if 4-chloronitrosobenzene is treated with sulfuric acid in acetic acid at 20 °C the fV-oxide is formed (Scheme 21). 

W 0 H L - A U E Phenazine synthesis Synthesis of phenazine N-oxide from anilines and nitrobenzene... 

TTx represents the hydrophobicity of the substituents at position 10. Its positive coefficient (+0.75) suggests that the presence of highly hydrophobic substituents at position 10 increases the activity. The outlier (X = OH) is much more active than expected by 11 times the standard deviation. This may be due to the formation of a phenoxyl radical that interacts with DNA [48]. The other derivative (X = NH2) is also considered as an outher due to being much more active than expected by 14 times the standard deviation. This anomalous behavior may be attributed to its nature as an aniline. This could result in hydrogen abstraction, or involve microsomal N-oxidation [48,49]. 

A detailed investigation of aniline N-methylation on Cui xZnxFc204 was carried out through in situ FTIR spectroscopy. The reactants (aniline and methanol) and possible products (NMA, DMA and o-toluidine) were adsorbed on the catalysts and analyzed [106,107]. Adsorption of methanol indicated a dissociative chemisorption as methoxy species on catalyst surface at 100°C. As the temperature increased, oxidation of methoxy species to formaldehyde to dioxymethylene to formate species was observed, and above 300°C complete oxidation takes place to CO, CO2 and H2. Indeed methanol alone on Cui xZnxFc204 and Cui.xCoxFc204 behaves in a similar way [79,107]. 

T Cl Hj/(ranA-Pd(py)2Cl2/C2HsOH/NaOH Normaldruck 30 10 h 4-Chlor-anilin ( + Bis-[4-chlor-phenyf]-diazen-N-oxid) 60 [ + 20] 3... 

Various substituted anilines are converted into nitroarenes 9.12 while octaethylporphyrin N-oxide is obtained in the reaction of hypofluorous acid with octaethylporphyrin.13... 

Hyperfine shifts (ppm) pyridine-N-oxide of ring nuclei in octahedral complexes of Ni2+ with aniline and... 

N-Oxidation. (V-oxidation can occur in a number of ways, including hydroxylamine formation, oxime formation, and N-oxide formation, although the latter is primarily dependent on the FMO enzyme. Hydroxylamine formation occurs with a number of amines such as aniline and many of its substituted derivatives. In the case of 2-acetylaminofluorene the product is a potent carcinogen, and thus the reaction is an activation reaction (Figure 7.6). 

The amino structure for 9-aminoacridine (77) has been confirmed by IR studies (65JCS5230), and NMR spectral data in DMSO are consistent with the diamino structures (78) and (79) (64JCS1423). Amino groups on fused benzene rings and /3 to nitrogen in hetero rings exist in the amino form, and the reactions of these compounds are similar to those of aniline and the naphthylamines. Aminopyridine N-oxides exist very predominantly in the amino form (57JCS4375). 

Reaction of a primary aliphatic amine, n-butylamine, with nitronium tetrafluoroborate in methylene chloride or acetonitrile produced not n-butylnitramine, but n-butyl nitrate in about 20% yield. However, treating an electronegatively substituted primary aromatic amine, picramide, with nitronium tetrafluoroborate did give the primary nitramine, N,2,4,6-tetra-nitroaniline, in 85% yield. Olah (16) had reported previously that aniline was oxidized vigorously by nitronium salts. 

Aniline, N-allenyl-, cycloaddition of nitrile oxide and rearrangement, 60, 304 Anilines, A,7V-dialkyl-3-alkoxy-, lithiation, 56, 260... 

Disposition in the Body. Readily absorbed from the skin and mucous membranes. Metabolised to 4-aminophenol and 4-acetamidophenol which are excreted in the urine as glucuronide and sulphate conjugates. 7V-Phenylsulphamic acid (aniline N-sulphate) is also a metabolite. The main toxic effect of aniline, the formation of methaemoglobin, is thought to be due to an oxidation product of aniline, phenylhydroxylamine. 

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