Chemistry of iminofurans: XIV. Ring opening of 5-substituted furan-2,3-dione 3-benzoylhydrazones by the action of aromatic and heterocyclic amines

Reactions of 5-aryl- and 5-tert-butyl-3-(benzoylhydrazinylidene)furan-2,3-diones with aromatic and heterocyclic amines afforded 4-aryl-2-(benzoylhydrazinylidene)-4-oxobutanamides and 5,5-dimethyl-2-(benzoylhydrazinylidene)-4-oxohexanamides which exist in solution as mixtures of hydrazone and cyclic dihydropyrazole tautomers.