Approaches for the preparation of pyridazines and fused pyridazines are reviewed. Some corrections about errors in the old literature are given and discussed. The %yields of selected examples are optimized.
Keywords: Pyridazines, synthesis, % yield optimization, heterocyclic nucleus, spectroscopic data, lone pair delocalization, cf. resonance, reactions of Mannich bases, Vilsmeier reactions, HMBC data, benzenediazonium chloride, aromatic diazonium salts, malononitrile, phthalazines