Synthesis and Biological Activity of Pyridopyridazine Derivatives: A Mini Review

This review presents most of the literature data about synthesis and biological activity of pyridopyridazine derivatives. There are six structural isomers of the bicyclic ring system containing pyridine moiety condensed with pyridazine nucleus. Pyridopyridazine derivatives show antitumor, antibacterial, analgesic and diuretics activities. The derivatives have been identified as the selective phosphodiesterase 5 and phosphodiesterase 4 inhibitors. Pyridopyridazines are novel class of GABA-A receptor benzodiazepine binding site ligands. Some of pyrido[3,2-c]pyridazine derivatives possess molluscicidal activity and can be used as biodegradable agrochemicals. The broad spectrum of biological activity of pyridopyridazine derivatives is the main reason for the preparation of new compounds containing this scaffold.