The Ullmann Reaction of 1, 5-Dichloroanthraquinone

Abstract

A series of oligomeric anthraquinones including 5, 5'-dichloro-1, 1'-bianthraquinone [2] 5, 5"-dichloro-1, 1': 5', 1"-teranthraquinone [3] and 5, 5'"-dichloro-1, 1': 5'', 1"': 5", 1''' quateranthraquinone [4] have been obtained by the Ullmann reaction of 1, 5-dichloroanthraquinone with copper powder in nitrobenzene. Several dehalogenated products (e. g.5-chloro-1, bianthraquinone[9])and amines (e. g.5, 5'-dichloroN-phenyl-1, 1'-iminodianthraquinone[6]) were also found to be formed in low yields. The isolated yields of oligorners [2]-[4]were almost identical with those calculated by a random distribution method. The reaction conditions for [2] were optimized with respect to the ratio of copper to [1].