A new method for the generation of azoalkenes from ketohydrazones and its application to the synthesis of tetrahydropyridazine derivatives

The reaction of ketohydrazones containing an α-methylene group with chloramine-T followed by treatment with triethylamine leads to the formation of azoalkenes via an α-chloroazo-compound, which can react intermolecularly and in situ with olefinic compounds to produce tetrahydropyridazine derivatives in good yield.