Synthesis of tetrasubstituted 1H-indazolo[1,2-b]phthalazinedione derivatives bearing three-dimensional turbine-type structures via domino reaction of phthalhydrazide and vinylketones

Abstract

A domino reaction of phthalhydrazide and vinylketone in the presence of phosphotungstic acid was successfully established, and 3D turbine-type tetrasubstituted 1H-indazolo[1,2-b]phthalazinedione derivatives were conveniently obtained with moderate to excellent yields (up to 95%). The highly efficient catalytic system exhibited broad substrate scopes under mild conditions. A 78% yield of the desired product was obtained when the reaction was conducted on a multi-gram scale.