Synthesis of 4-amino[1] benzofuro[3,2-g] cinnolines

The synthesis of the new heterocycles, 4-amino[1]benzofuro[3,2-g]cinnolines, was accomplished by the intramolecular cyclization of the Z -configuration of cyanoarylhydrazones. The latter compounds were obtained via interaction between the diazonium salt of 3-amino-dibenzofuran and various active methylene compounds via the Japp-Klingemann reaction. The alkaline treatment of azo intermediates 4 , which may be isolated in the course of condensation, gave the corresponding cyanoarylhydrazones 5 . A study of the configuration and possible isomerisations is reported.