Photoamination of 1-hydroxyanthraquinones

Photoamination of 1-hydroxyanthraquinone with n-butylamine gave not only 1- hydroxy-4-(butylamino)anthraquinone (5) but also 1-hydroxy-2-(butylamino)an thraquinone (6) in contrast with the amination of 1-aminoanthraquinones whe re only 4-amination occurs. The production ratio of 6 to 5 was 0.2 in the r eaction under air using acetonitrile and mixtures of acetonitrile and water as solvents, On the other hand, in the reaction under nitrogen the ratio i ncreased from 0.2 to 3.2 as the water content of the solvent increased from 0 to 50 vol.%. The reaction of 1-hydroxy-2-bromoanthraquinone and 1-hydrox y-2,4-bromoanthraquinone gave 1-hydroxy-2-bromo-4-(butylamino)anthraquinone only. (C) 2001 Elsevier Science B,V. All rights reserved.