Nuclear acylation of aromatic amines and formylation of various aromaticThe reagent has also compounds in polyphosphoric acid are described. been used for preparing aromatic sulphones and in the Skraup reaction.INTERMOLECULAR acylation catalysed by polyphosphoric acid is a known preparative methodl for various aromatic ketones. Amino-ketones have so far not been made by this procedure, as ring-positions of aromatic amines were reported to be inactive. For instance, Snyder and Elston obtained only N-substituted amides by reaction of aromatic aminrts with acids in polyphosphoric acid. We have now found that on prolonged treatment some aminobenzophenones can be made in a more convenient way and better yield than p r e v i o ~s l y . ~~~ For instance, 4-aminobenzophenone was produced in 84% yield by heating benzanilide and benzoic anhydride in polyphosphoric acid at 150" for 3 hr. Other acylating agents were used less successfully with benzanilide and the method was also applied to other aromatic amines as set out in Table 1. The low yield with benzamide as the acylating source is undoubtedly due to the hydrolytic resistance of amides towards polyphosphoric acid.We also studied methods of formylating aromatic compounds in polyphosphoric acid. Hexamethylenetetramine was found to be a good formylating agent at about 160". The results differed notably in some cases from other aldehyde syntheses, including the Duff reaction which uses the same formylating agent. Thus phenol, anisole, and cresols gave a dialdehyde, easily separable from the accompanying resinous material by steamdistillation. Yields were small, but the simplicity of the method makes it more practicable than reported procedures for dialdehyde formation. Halogeno-and nitro-phenols furnished monoaldehydes which are not usually accessible by other direct formylation procedure^.^ Formation of $-fluorobenzaldehyde in 20% yield compares favourably

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