Synthesis of Imidazo-1,3-diazabiphenylene (lin-Benzocyclobutadienopurine), a Ring System Having a Benzocyclobutadieno Spacer between the Terminal Rings of Purine.

Article abstract of DOI:10.1021/jo00214a011

Two distinct syntheses of the pyrimido<6,5-i>imidazo<4,5-g>cinnoline ring system have been accomplished.The first of these began with 2-acetamido-4-chloro-5-nitroacetophenone, which was elaborated sequentially by fusion of the imidazole, pyridazine, and p