REARRANGEMENTS OF DIPHENYLAMINE DERIVATIVES .2. REARRANGEMENT OF SOME N-AROYLDIPHENYLAMINES AND INTERMOLECULAR CHARACTER OF REACTION

The rearrangement of N-anisoyl-,N-(p-chlorobenzoyl)- or N-(p-nitrobenzoyl)-diphenylamine in polyphosphoric acid at 110-160° yields mainly the corresponding 9-arylacridine with, in the first two cases, diphenylamine and the 4,4′-diaroyldiphenylamine. N-Aroyl-4,4′- dialkyldiphenylamines give good yields of 2,7-dialkyl-9-arylacridines under similar conditions, and a mixed rearrangement with N-benzoyl-4,4′- diethyldiphenylamine and N-(p-chlorobenzoyl)-4,4′-dimethyldiphenylamine reveals that migration of the aroyl group to the ortho-position in these reactions proceeds by an intermolecular mechanism.