Amines oxidation with peroxy acids

Amines are known to undergo oxidation with the use of peroxy acids and can result in various products depending on the reaction conditions. Primary amines react with peroxy acids to yield nitroso compounds via the formation of hydroxylamines. The nitroso derivatives can subsequently be oxidized further to nitro compounds under more vigorous conditions. ... 

When the unsaturated tertiary amine, pitprofen (179 R = H) is treated with MCPBA the reaction takes place selectively at the mwe nucleophilic nitrogen to furnish the corresponding amine oxide with the alkene moiety intact. In contrast, peroxycarboximidic acid, prepared in situ from acetonitrile/H202. reacts selectively with the alkene moiety of the ester (179 R = Me equation 65). The sterically hindered nitrogen of (179) is able to react with peroxy acids which have a low steric demand, but not with peroxy-caiixrximidic acids which have a large steric demand. 

Tertiary alkylamines can be converted into the corresponding N-oxides with hydrogen peroxide or with peroxy acids." r-Butyl hydroperoxide has also been used in the presence of a catalyst such as VO(acac)2. Sharpless and coworkers have carried out the oxidative kinetic resolution of several p-hy-droxy tertiary amines such as (41) with r-butyl hydroperoxide, titanium(rv) isoprcqtoxide and (-i-)-diiso-propyl tartrate, the titanium(rv) tartrate ratio being ateut 2 1." After 60% conversion, one enantiomer was selectively oxidized, and the other enantiomer could be recovered in good optical purity (Scheme... 

In a number of reactions the Polonovski products are obtained directly on reaction of a tertiary amine with peroxy acids. This can happen when the peroxy acid is present in excess, in which case it acts as both the oxidizing and activating agent, or when an appropriately positioned acid or amide group, which can act as an internal activator, is present in the -oxide. The latter situation is illustrated by the efficient conversion of compound (74) to the benzimidazole (75 Scheme 16). ... 

Oxidative deamination of a secondary amine to the ketone can be effected by formation of the imine with 2-pyridinecarboxaldehyde, reaction of the imine with peroxy-acid to form the oxaziridine, and alkaline hydrolysis (KOH-H2O-DMF-MeaCO). The steps are illustrated for 3a-amino-5a-cholestane (235), leading to (239) a IVa-aminoandrostane also gave the corresponding ketone. ... 

Oxidation of corresp. amine with peroxy acid/... 

Aromatic and aliphatic primary amines can be oxidized to the corresponding nitro compounds by peroxy acids and by a number of other reagents. The peroxy acid oxidations probably go by way of intermediate hydroxylamines and nitroso compounds (Scheme 2). Various side reactions can therefore take place, the nature of which depends upon the structure of the starting amine and the reaction conditions. For example, aromatic amines can give azoxy compounds by reaction of nitroso compounds with hy-droxylamine intermediates aliphatic amines can give nitroso dimers or oximes formed by acid-catalyz rearrangement of the intermediate nitrosoalkanes (Scheme 3). 

Active carbonyl compounds interfere by forming acetals or ketals by reaction with methanol. The interference can be avoided by adding hydrogen cyanide to form cyanohydrins that do not interfere. Other interfering substances include mercaptans and certain amines, which react with iodine, and various oxidizing substances such as peroxy acids, diacyl peroxides, and quinones, which react with iodide to produce iodine. 

Detoxification procedures from mustard gas are difficult because of its insolubility and also because of the drastic effects it can have on lung epithelial tissue following inhalation. During World War I, physicians had no curative means of treating the victims of mustard gas exposure. The only method of detoxification that was known involved a rather extreme oxidation procedure using superchlorinated bleaches, such as 5% sodium hypochlorite. Today, several novel methods of detoxification have been developed to counter the effects of mustard gas and these include the use of sulphur-amine solutions and magnesium monoperoxyphthalate. The most effective method to date employs peroxy acids, because they are able to react quickly with the mustard gas. 

Oxidants suitable for the partial oxidation of amines to nitroso compounds are peroxy acids Caro acid, which is prepared in situ from potassium persulfate and sulfuric acid [195, 199 potassium peroxysulfate (Oxone) [295] peroxyacetic acid [i53], and peroxybenzoic add [1186], 3-Nitro-o-toluidine [195] and 5-nitro-o-toluidine [199] in aqueous-alcoholic solutions, when treated with a mixture of potassium persulfate and concentrated sulfuric acid, give 3-nitro-2-nitrosotoluene and 5-nitro-2-nitrosotoluene in respective yields of 60 and 55-66%. Organic peroxy acids convert 2,6-dihaloanilines into 2,6-dihalonitrosobenzenes (equation 497) [753, 1186]. p-Phenylenediamine (1,4-diaminobenzene) is oxidized by Oxone (2KHS05 KHS04 K2S04) in an aqueous suspension at room temperature to p-dinitrosobenzene in a quantitative yield [205]. 

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