Rearrangements of diphenylamine derivatives. Part I. The rearrangement of N-benzoyldiphenylamine and some related acylation reations

The Fries-type rearrangement of N-benzoyldiphenylamine in the presence of polyphosphoric acid at 130° affords 4,4′-dibenzoyldiphenylamine, 9-phenylacridine, and 2,7-dibenzoyl-9-phenylacridine. The same products, together with N-benzoyldiphenylamine, are obtained from diphenylamine, an excess of benzoic acid, and polyphosphoric acid at 100°, but at 160° the latter reaction takes a slightly different course and 2-benzoyl-9-phenylacridine is one of the products. The reaction of diphenylamine with dodecanoic acid in polyphosphoric acid gives 2-dodecanoyl-9-undecylacridine, but with acetic acid under similar conditions only N-acetyldiphenylamine or intractable products are formed.