Heteroelectrocyclic reaction of 4-azido-3-hydrazonoalkylquinolines to 2-arylaminopyrazolo[4,3-c]quinolones

4-Azido-3-acylquinolones 4 obtained from 4-hydroxy derivatives 1 via tosylates 3 or chlorides 5, reacted with arylhydrazines 6 to generate 4-azido-3-hydrazonoalkylquinolines 7. Thermolysis of 7 gave ring closure products which were assigned to 2-arylaminopyrazolo[4,3-c]quinolones 10. The thermal decomposition conditions of the azides 4 and 7 were studied by differential scanning calorimetry (DSC).