Unexpected formation of pyridazine-5,6-dione derivatives in the reactions of 3-arylhydrazono-2,4-dioxo-4-pentafluorophenylbutanoates with hydrazines

The reactions of 3-arylhydrazono-2,4-dioxo-4-pentafluorophenylbutanoates with hydrazine hydrate and phenylhydrazine resulted in the formation of 4-arylazo-3-pentafluorophenyl-1,2-dihydro-5H,6H-pyridazine-5,6-diones or 6-aryl-2-phenyl-7,8,9,10-tetrafluoro-2,3,4,6-tetrahydropyridazino[4,3-c]cinnoline-3,4-dione.