Facile preparation of 6-chloro-9-amino-2-hydroxyacridine, a urinary metabolite of quinacrine and quinacrine mustard.

6-Chloro-9-amino-2-hydroxyacridine was found to be a metabolite of both quinacrine and the antimalarial alkylating agent quinacrine mustard. Its structure was confirmed by a one-step reaction of quinacrine with 48 percent hydrobromic acid. The presence of this compound as a metabolite of quinacrine mustard suggests a possible in vivo activation mechanism for its antitumor activity and a pharmacological basis for its toxicity to the liver. In vitro experiments showed that this new compound does react with chromosomes and, therefore, can be both a useful chromosome stain and an intercalating agent.