Oximes conversion into amides

An important reaction of oximes (e.g. R2C = NOH) is their conversion into amides (e.g. RCONHR) in the Beckmann rearrangement reaction. 

By treatment of this oxime with phosphorus pentachloride or thionyl fhloride in ether solution, smooth conversion into benzanilide, m.p. 163°, results. The change of any oxime into a substituted amide under the conditions mentioned is usually termed the Beckmann rearrangement. The above example may be represented ... 

The conversion of oximes into amides or lactams (reactions 6 or 7), in particular, e-caprolactam from cyclohexanone oxime (X = H), is catalyzed by [NBu4][Re04] andCFsSOsH in refluxing nitromethane, via a postulated perrhenic ester of oxime [RR C=N-0-Re03]. ... 

Sulphurated borohydrides can reduce oximes to amines the intermediate hydroxylamines are isolable. Sodium borohydride reduces nitriles to amines in high yield in the presence of Raney nickel as catalyst. The titanocene-promoted fixation-reduction of molecular nitrogen has been utilized in the conversion of ketones into amides and acid chlorides into nitriles in an overall reductive deoxygenation, as exemplified in Scheme 109. 

A catalytic route for nucleophilic substitution of alcohols using simple CPN 55 as a catalyst was also developed by Lambert in 2011 (Scheme 6.18a) [46]. In this reaction, oxalyl chloride acts as an activating reagent for 55. The catalytic system is also employed for the conversion of oximes and primary amides into nitriles (Scheme 6.18b) [47]. 

Owston NA, Parker AJ, Williams JMJ (2007) Iridium-catalyzed conversion of alcohols into amides via oximes. Org Lett 9(l) 73-75... 

The conversion of oximes, which are readily available from ketones, into amides is known as the Beckmaim rearrangement [354]. This reaction has been used exten-... 

Another mild method for the activation of the oxime hydroxyl group consists in its conversion into an ester moiety or, more commonly, into a sulfonate derivative. They can be rearranged into amides under basic [371] or acidic [372] conditions also involving Lewis acids [366]. Trimethylsilyl chloride [373] and chloroformate [374] in the presence of a Lewis acid can also be used. Amidines have been obtained by Beckmann rearrangement of a tosyloxime in the presence of benzotriazol [375]. 

A mixture of polyphosphoric acid and nitromethane converts fluorenone into phenanthridone at 250°. The reaction probably proceeds via the oxime, which can be isolated when the reaction is carried out at 190°.107 The same conversion can be achieved, though in lower yield, by the action of sodamide on fluorenone in liquid ammonia or (-butylamine. In this reaction biphenyl-2-carboxamide (isolated in 5% yield) is probably a precursor of phenanthridone, since the conversion of the amide to the latter in 40% yield has been demonstrated in a second experiment. The major product of the reaction with fluorenone in liquid ammonia is, not surprisingly, fluorenimine.108... 

Benzoxazoles. - Both o- and m-halogenobenzanilides (413) are converted into the amidines (415) by potassium amide in liquid ammonia these are formed by aryne cyclization to 2-phenylbenzoxazole (414) and subsequent aminoly-sis." The conversion of acetophenone oxime into 2-methylbenzoxazole by the action of phosphorus oxychloride involves a Beckmann rearrangement. Pyrolysis of aryl azidoformates, ArOaCNa, gives benzoxazol-2-ones. The azide (416) is converted into the benzoxazole (417) on heating. The... 

Beckmann rearrangement The chemical conversion of a ketone oxime into an amide, usually using sulphuric acid as a catalyst. The reaction, used in the manufacture of nylon and other polyamides, is named after the German chemist Ernst Beckmarm (1853-1923). 

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