Ra. Mekheimer, Fused quinoline heterocycles. II. First synthesis of 1,2,3,4,5-hexaazaaceanthrylenes and 5,7,8,10a,11-pentaazabenzo[a]-fluorenes, SYN COMMUN, 31(13), 2001, pp. 1971-1982
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.