The Synthesis and Dimerization of 10-chlorobenzanthrone

Abstract

10-Chlorobenzanthrone (6) was synthesized from chlorobenzene by a 5-stage reaction. In the last stage, p-chlorophenyl-α-naphthylketone had been reported to give (6) only in 5% yield, but it was found that the addition of sodium chloride in the reaction medium increased the yield to 25%.
(6) was treated with manganese dioxide in the mixture of polyphosphoric acid and conc. sulfuric acid to give 10, 10′-dichloro-3, 3′-dibenzanthronyl in 29% yield.
By the Ullmann coupling reaction of (6), the expected 10, 10′-dibenzanthronyl could not be prepared, but dichlorodibenzanthronyl was obtained.