Recent progress in pyridazin-3(2H)-ones chemistry

Although Fischer obtained the first pyridazines as early as 1886, major attention has been devoted to their chemistry only in the early few decades. However, pyridazin-3(2H)-ones and their fused ring derivatives have recently received much more attention to possess various biological activities and also to use new synthetic auxiliaries. The scope of the present review is to summarize from 1990 as the followings; the construction of pyridazin-3(2H)-one ring, the reaction of ring nitrogen (N2), the reaction of ring carbons at C3, C4, C5 and C6 and the application of pyridazin-3(2H)-one derivatives in the synthetic chemistry.