Azidoacridines: Potential nucleic acid mutagens

Thermolysis of 9-azidoacridine (free base) in boiling nitrobenzene or o-dichlorobenzene, or photolysis in methanol, affords 9,9'-azoacridine in high yield; thermolysis in boiling decalin yields 9-aminoacridine. The formation of these products probably involves reactive nitrene intermediates. In contrast, the azide groups of 9-azidoacridine hydrochloride and 9-azido-10-methylacridinium methyl sulphate are readily displaced as hydrazoic acid by nucleophiles. The hydrochloride and methyl quaternary salt are rapidly hydrolysed to acridone and N-methylacridone respectively in water, and react with aromatic amines (in the former case), and with aromatic and aliphatic amines (in the latter case) to afford substituted 9-aminoacridines. 3-Azidoacridine and its salts are more stable than the 9-azido-analogues.