Synthesis of pyridazines via furan vinamidinium salts

Reaction of 5-(N,N-dimethylamino)-2-furfurylidene-N,N-dimethyliminium bromide ( I ) with hydrazine affords 3-hydrazono-2,3,4,5-tetrahydro-6-methylenehydrazonopyridazine ( III ). 5-(N,N-Dialkylamino)-2-arylazofuran salts II react with the same reagent to give 3,6-disubstituted pyridazines V . The structure of the synthesized compounds was identified by 1 H NMR and mass spectra.