title: Photochemical and thermal transformations of 1-aryloxy-2- and 4-azidoanthraquinones.
abstract: The photolysis of 1-aryloxy-2-azidoanthraquinones (3) in benzene is described herein which gave 1-hydroxy-2-arylaminoanthraquinones (4) and two types of 5H-naphtho[2,3-c]phenoxazine-8,13-diones (5 and 6). Thermolysis of 3 yielded only one of phenoxazines 5 and small amount of 4. On the other hand thermolysis of 3 in the presence of phenols gave phenoxazine 6 as a major product. The mechanism of the photolysis and thermolysis of 2-azido-1-aryloxyanthraquinones (3) is proposed and supported by the results from semiempirical calculations. A relative contribution of the primary photoreactions-azido group dissociation and aryl group migration was estimated to be 3:1. Photolysis and thermolysis of 4-azido-1-(p-tert-butylphenoxy)-9,10-anthraquinone (8) gave 3-(p-tert-butylphenoxy)-anthra[1,9-cd]-izoxazole-6-one (9) as the only product.
authors.affiliation: Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 9, Lavrenteva av., 630090 Novosibirsk, Russia. klimenko@nioch.nsc.ru
authors.forename: Lubov S
authors.initials: LS
authors.lastname: Klimenko
authors.forename: Elena A
authors.initials: EA
authors.lastname: Pritchina
authors.forename: Nina P
authors.initials: NP
authors.lastname: Gritsan