Cyclization of Anthraquinone Oligomers

Abstract

By treatment with copper powder in conc. sulfuric acid, 5, 5'-dichloro-1, 1'-bianthraquinone [1b] gave 8, 15-dichloro-7, 16-dihydrodibenzo[a, o]perylene-7, 16-dione [2b]. [ Under similar conditions, 5, 5''-dichloro-1, 1': 5', 1''-teranthraquinone [4], or 5, 5''-dichloro-1, 1': 5', 1'': 5'', 1''-quateranthraquinone 9D also afforded the corresponding cyclized product: 4, 15-dichlor o5, 16-dihydrodibenzo[fg, qr]dinaphtho[1, 2, 3-jk, 1', 2', 3'-uv]pentacene-5, 16-dione [6] or 15, 15'-dichloro-7, 7', 16, 16'-tetrahydro-8, 8'-bi (dibenzo[a, o]perylene) -7, 7', 16, 16'-tetrone [11]. Contrary to [2b], [6] or [11] was not so stable that the reverse reaction to yield [4 ] or [ 9 ] was detected even in the solid states. Upon irradiation, [2b], [6 ]or [11] cyclize d further to give 1, 6-dichloro-7, 14-dihydrophenanthro[1, 10, 9, 8-opqra]perylene-7, 14-dione [3b], 3, 12-dichloro-4, 13-dihydrodianthra[1, 9, 8-abcd, 1', 9', 8'-jklm]coronene-4, 13-dione C 8 or 6, 6'-dichloro-7, 7', 14, 14'-tetrahydro-1, 1'-bi (phenanthro [1, 10, 9, 8-op gra] perylene) -7, 7', 14, 14'tetrone [13], respectively. Direct synthesis of [8] from [4] was also studied.