Synthesis of 1,3,5-tris[4-(diarylamino)phenyl]benzene and 1,3,5-tris(diarylamino)benzene derivatives

The title compounds were prepared by the copper catalysed Ullmann coupling of aromatic amines with aromatic aryl iodides. Full spectroscopic details are reported. Solutions of 1,3,5-tris(diarylamino)benzene derivatives in deuterated chloroform undergo hydrogen-deuterium exchange on the central ring and readily turn green owing to partial oxidation by traces of dissolved oxygen. The green colour is quenched by the addition of ascorbic acid. The solutions are more stable in chloroform that has been filtered through basic alumina to remove traces of acid. N-Arylbenzenesulfonamides can be converted to diarylamines by treatment with the sodium salt of an aniline.