Synthesis of Pyridazin-3(2H)-one Derivatives by the Reaction of CH-Acids with Dichlorodiazadienes

The reactions of 4,4-dichloro-1,2-diazabuta-1,3-dienes with dimethyl malonate, cyanoacetic esters and ethyl acetoacetate provided straightforward access to highly functionalized pyridazine derivatives. The approach was found to be very general for the highly efficient synthesis of various pyridazine derivatives which can be isolated in moderate to excellent yields. The possibility of their subsequent functionalization was demonstrated. Moreover, the absorption characteristics in the UV/Vis-range and luminescence were studied for all synthesized compounds. © 2020 Wiley-VCH GmbH