Abstract A series of 1-substituted 4, 5-diformyl-[1, 2, 3] triazole derivatives were prepared by 1, 3-dipolar cyclo-addition of aryl azides with acetylene dicarboxaldehyde mono- diethylacetal. The triazoles were readily converted into 1-substituted [1, 2, 3] triazolo [4, 5-d] pyridazines in good yields. The 1-(2-nitrophenyl)-[1, 2, 3] triazolo [4, 5-d] pyridazine was found to be a useful intermediate for the generation of the novel 5H-benzo [1, 2, 3] triazolo ...
