Reaction of triphenylamine with an aromatic carboxylic acid in polyphosphoric acid (PPA) gave 9-aryl-10-phenyl-9-acridanol (2) in yields as high as 50%, together with a mixture of para-acylated triphenylamines; acridanol 2 arises by cyclization of an intermediate ortho-acylated triphenylamine. Certain para-monoacylated triphenylamines were rearranged in PPA at 190° into the corresponding acridanols 2 in ∼50% yield; p-di- and -tribenzoyltriphenylamines under similar conditions gave nuclear-substituted acridanols. The intermolecularity of the above transformations is supported. Acylation of triphenylamine with acid anhydrides and acid chlorides in the presence of anhydrous stannic chloride proceeded readily in benzene solution and provided para-acylated triphenylamines.
|Number of pages||6|
|Journal||Journal of Organic Chemistry|
|Publication status||Published - 1968|