Arylcarboxylic acid amides

It is not necessary to use phosphorus oxychloride complexes of formamides, because Roh and Kochendorfer in 1937 demonstrated that the iminium chlorides themselves react similarly and Bosshard and Zollinger have shown that comparable yields can be obtained using chlorodimethylformiminium chloride as the reagent. However, in the synthesis of diarylketones good yields are only obtained when the phosphorus oxychloride complex of the corresponding arylcarboxylic acid amide has been used The synthesis of ketones from carboxylic acid amides, phosphorus oxychloride and suitable substrates predates the aldehyde synthesis by approximately 40 years but it is of only limited usefulness because side reactions are very often encountered... 

When an alkyl aryl ketone is heated with yellow ammonium polysulphide solution at elevated temperature, an aryl-substituted aliphatic acid amide is formed the product actually isolated is the amide of the tu-arylcarboxylic acid together with a smaller amount of the corresponding ammonium salt of the carboxylic acid. 

Arylcarboxylic acids. CO bubbled into a stirred soln. of startg. azosulfone and a little tetrakis(triphenylphosphine)palladium(0) in 1 1 benzene/acetic acid at 80° for 2 h benzoic acid. Y 76%. F.e. incl. esters and amides s. N. Kamigata et al., Bull. Chem. Soc. Japan 62, 605-7 (1989). 

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