Reactions of natural anthraquinone pigments

@article{Chumbalov2004ReactionsON,
  title={Reactions of natural anthraquinone pigments},
  author={T. K. Chumbalov and Raissa A. Muzychkina},
  journal={Chemistry of Natural Compounds},
  year={2004},
  volume={1},
  pages={283-285}
}
By condensing chrysophanic acid with nitrogen-containing substances, derivatives substituted at the carbonyl and hydroxyl-group positions have been obtained. Substance IIa possess antitumor activity.