Fused quinoline heterocycles. II. First synthesis of 1,2,3,4,5-hexaazaaceanthrylenes and 5,7,8,10a,11-pentaazabenzo[a]-fluorenes

The new tetracyclic ring systems 5-alkyl-1,5-dihydro-1,2,3,4,5,6-hexaazaace anthrylenes 5a-d were synthesized by diazotization of 4-alkylamino-3-amino- 1H-pyrazolo[4,3-c]quinolines 4a-d. The 4-arylamino-3-diazo-1H-pyrazolo-[4,3 -c]-quinolines 6e-h, which were prepared by diazotisation of the correspond ing amines 4e-h, readily formed the novel tetracyclic ring system ethyl 6-a rylamion-10-methyl-5,7,8,10a,11-pentaazabenzo[a]fluorene-9-carboxylates 8e- h, when treated with ethyl acetoacetate.