Aryl ketones amides

In the alkyl aryl ketones, the aryl groups migrate preferentially, yielding V-aryl amides. 

When an alkyl aryl ketone is heated with yellow ammonium polysulphide solution at an elevated temperature, an aryl substituted aliphatic acid amide is foimed the product actually isolated is the amide of the ci-aryl carboxylic acid together with a smaller amount of the corresponding ammonium salt of the oarboxylio acid. Thus acetophenone affords phenylacetamide (50 per cent.) and ammonium phenylacetate (13 per cent.) ... 

Acylation (Sections 16.3,21.4) The introduction of an acyl group, —COR, onto a molecule. For example, acylation of an alcohol yields an ester, acylation of an amine yields an amide, and acylation of an aromatic ring yields an alkyl aryl ketone. 

Cleavage of aryl ketones with amide ions (Haller-Bauer)... 

A procedure has been developed for the palladium-catalysed a-arylation of amides by aryl bromides using the zinc enolates of the amides. The reaction works well with bromoarenes carrying a variety of ring substituents and with bromopyridine. In addition, the reaction has been shown to be effective with morpholine amides to give products which are precursors for aldehydes and ketones.39 A new method has been reported for the allylation of aryl halides using homoallyl alcohols as the allyl source the palladium-catalysed reaction, which may be both stereo- and regio-sepecific, uses a retro-allylation reaction to form a a-allyl(aryl)palladium intermediate.40... 

The Willgerodt Reaction allows the synthesis of amides from aryl ketones under the influence of a secondary amine and a thiating agent. The mechanism involves the formation of an enamine which undergoes thiation, and the carbonyl group migrates to the end of the chain via a cascade of thio-substituted iminium-aziridinium rearrangements. 

Cleavage by sodium amide is a general reaction of diaryl ketones, hexaalkylacetones, and <-alkyl aryl ketones. The reaction has found preparative value in the cleavage of trialkylacetophenones to amides of trialkylacetic acids (method 248). Fission occurs when the ketones ate refluxed with sodium amide in benzene, toluene, or xylene solutions. 

A, A -Disubstituted selenoureas react with a-bromoesters, amides, nitriles, and bromomethyl aryl ketones to give the corresponding salts. Treatment of the salts with Et3N or NaH gives the corresponding 1,3-selenazoles (Scheme 7) <2000HCA1576>. 

The most important method for the preparation of aryl ketones is known as Friedel-Crafts acylation. The reaction is of wide scope. Reagents other than acyl halides can be used," including carboxylic acids," anhydrides, and ketenes. Oxalyl chloride has been used to give diaryl 1,2-diketones." Carboxylic esters usually give alkylation as the predominant product (see 11-11)." A-Carbamoyl p-lactams reacted with naphthalene in the presence of trifluoromethanesulfonic acid to give the keto-amide." ... 

Fig. 4. Plot of the carbonyl NMR chemical shift for aryl acids O (33), aryl amides (33), aryl esters (33), aryl acid chlorides ffl(37), and aryl ketones (32) verus torsion angle between the aryi ring and the carbonyl functional group.

Tetrahedral transition state analogues of ester and amide substrates are known to function as efficient enzyme inhibitors of hydrolytic enzymes such as serine and aspartyl proteases as well as metalloproteinases (see Fig. 1.24) [141-144], Although ketals of alkyl or aryl ketones are usually not stable, those of difluroalkyl or trifluoromethyl ketones have considerable stability, as exemplified by their facile formations of the corresponding stable hydrates [145, 146]. Therefore, substrate analogues, containing difluoroalkyl or trifluoromethyl ketone moiety in appropriate positions, have been studied as effective transition state inhibitors of hydrolytic enzymes [141, 147-150],... 

The formation of an a-chloroenamine 1, which underwent ring contraction to a bicyclo-[3.1.0]hex-6-yliminiumion 2, has been suggested as a likely pathway similar intermediates have been considered to be involved in the formation of Favorskii amides in the reaction of a-halo-a -aryl ketones with secondary amines (for related ehemistry see Seetions 5.2.3.3.-3.4.). Indeed, the A, 7)f-dimethylcyclopropiminium ion was prepared from cyclopropanone via 1,1 -bis(dimethylamino)cyclopropane. ... 

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