Hypohalites reactions with

Upon treatment of primary amides with hypohalites, primary amines with one less carbon are obtained via the intermediacy of isocyanate. Also know as the Hofmann degradation reaction. 

Boron trifluoride and boron trifluoride-diethyl ether complex can be used as a source of fluoride ions in the presence of hypobromites and hypochlorites, e.g. methyl hypobromitc, tert-butyl hypobromite, methyl hypochlorite in carbon tetrachloride at 25 C. The addition of bromine monofluoride" and chlorine monofluoride" to various alkenes is accompanied by the formation of the corresponding alkoxybromides and alkoxychlorides which hinder the isolation of the halofluorinated products.57 jV-Bromo- and A -chloro-substiluted alkyl- and arylamines. -amides, and -imides, A -chloro-A,-methylamine, A -bromo-A -methylamine, A -chloro-A, /V-dimethylamine, A-bromo-A.A-dimethylamine, ACV-dichloro-A -methylamine, V,fV-dibromo-,V-mcthylaminc, A -bromosuccinimide, -V-chlorosuccinimide, Af-bromoacct-amide, A.A -dichlorourethane, can be used in the reaction instead of the hypohalites. The reactions with various alkenes conducted in dichloromethane at room temperature in the presence of boron trifluoride-diethyl ether complex produce bromofluoro and chlorofluoro addition products in 40-80 % yield. However, the reactions are complicated by the addition of A -halo-succinimides and Af.A-dichlorourcthane to the C = C bonds.58... 

The acyl hypohalit reaction with iodine ob a halogen component is the well-known Prevost reaction,18i0 whioh has found some application during recent years in the field of natural prodwtB.. u. . w. In thiB ease the acyl hypoholite is acetyl hypoiodite, generated by reaction of iodine with silver nitrate in glacial acetic arid (Eq. 130). 

Hypohalite ions reaction with ozone [OZONE] (Vol 17)... 

Reaction With Halogen Electrophiles. The synthesis of 1-haloaziridines, which are prone to explosion, has been carried out using hypohalites (290,291). 1-Chloroaziridine [10165-13-6] produced in this way reacts with 1-lithiated ethyleneimine to give l,l -diaziridine [4388-03-8]. Perchlorylaziridine [112405-46-6] has been prepared by reaction of ethyleneimine with dichlorine heptoxide at —20°C (292). 

Unfortunately, the reverse reactions, namely the transformation of aryl chlorides to aryl bromides or iodides upon reaction with the corresponding hypohalites, do not give satisfactory yields. 

Acylureas react with hypohalite in alkali to yield A-haloureas which are converted into oxadiazolinones (94). Rearrangement of the N-halourea to an isocyanate presumably occurs during the reaction (Scheme 17). 

Reaction of hydrogen peroxide with hypohalites has been examined in acidic solutions and, very much less completely, under alkaline conditions. The reaction of hydrogen peroxide and chlorine in hydrochloric acid proceeds according to equation (16), with a rate law (17)... 

An interesting reaction, giving an acid with the same number of carbon atoms, takes place when some ketones (having a and a hydrogens) are stirred for 10-60 min at 25-80 °C with powdered potassium hydroxide, carbon tetrachloride, water, and ten-butyl alcohol [954] (equation 418). Ketones with a hydrogens but not a hydrogens give the same product as that obtained by oxidation with hypohalites [954. ... 

Aryl methyl ketones give generally high yields of acids on treatment with hypohalites [6SS, 696,698, 736. The reaction of 1,3,5-triacetylbenzene and sodium hypochlorite results in a 94% yield of trimesic acid [655], and that of methyl p-naphthyl ketone and sodium hypochlorite gives an 87-88% yield of p-naphthoic acid [695]. 4-Acetyl-4 -methoxybiphenyl is converted... 

It is known from Houben-Weyl, Methoden der organischen Chemie, volume 8, pages 415-416, that carboxylic acids can be manufactured by oxidation of methyl ketones with hypohalites in an aqueous medium. The publication recommends dispersing the ketone by means of oxidation-resistant emulsifiers or carrying out the reaction in the presence of dioxane all the examples were carried out in this way. In most cases the reaction only takes place satisfactorily with hypobromite solutions, which are more expensive and less stable than hypochlorite solutions. For this reason alone, industrial utilization of the reaction is confined to special reactions with aromatic ketones. 

Diazirine was used as the carbene precursor in an experiment to make diazomethane from methylene and nitrogen in the gas phase. As shown by means of labeled nitrogen, there was 4% diazomethane formation. During the past 10 years thermal as well as photochemical decomposition of 3-chloro- and 3-bromodiazirine has been investigated in detail. Compounds 175 and 176 as well as analogous compounds are easily obtained by reaction of amidines with hypohalites according to Graham. ... 

The latter is an extremely reactive species. The inductive effect of the trifluoroacetyl group makes it a good leaving group, and facilitates cleavage of the O-Br bond during reaction with an aromatic compound. The acyl hypohalites are also the active... 

The same reaction with chlorine or bromine, on the other hand, produces a halide and a hypohalite ... 

The mechanism by which hypohalites oxidize alcohols probably involves initial formation of an alkyl hypohalite (Eq. 16.16). This product arises from reaction of the alcohol with the hypohalous acid that is in equilibrium with hypohalite ion in aqueous medium (Eq. 16.15). Base-promoted E2 elimination of the elements of H-X from the alkyl hypochlorite leads directly to either an aldehyde or ketone. The advantage of using hypohalite as an oxidant is immediately obvious upon examining Equation 16.16. The inorganic by-product derived from the oxidant is a halide salt that can be safely flushed down the drain. Reactions that do not produce toxic by-products are environmentally friendly and are now commonly referred to as "Green Chemistry." (See the Historical Highlight at the end of this chapter.)... 

Some side reactions may complicate the oxidation of a primary alcohol to an aldehyde using hypohalous acid. For example, an aldehyde may undergo reaction with an additional equivalent of hypohalite to form a carboxylic acid (Eq. 16.17), a process that may be initiated by acid-catalyzed formation of the hydrate of the intermediate aldehyde as shown in Equation 16.18. Subsequent steps in the oxidation are then analogous to those for converting an alcohol to an aldehyde or ketone (Eq. 16.16). It may be difficult to suppress this further oxidation, so unless carboxylic acids are the desired products, the use of hypohalite as an oxidant is limited to the conversion of secondary alcohols to ketones. 

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