Mild basic ionic liquids catalyzed new four-component synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones

A new four-component synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives using three weak basic ionic liquids such as 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate, pyrrolidinium formate, and pyrrolidinium acetate as efficient catalysts for condensation reaction of hydrazine monohydrate, phthalic anhydride, malononitrile or ethyl cyanoacetate, and aromatic aldehydes under ambient and solvent-free conditions in excellent yields is described.

Graphical AbstractHighlights► 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate as the mild basic ionic liquids was used. ► Pyrrolidinium formate, and pyrrolidinium acetate were used. ► 1H-pyrazolo[1,2-b]phthalazine-5,10-diones were synthesised. ► The reusability of the ionic liquids was studied. ► This research shows priority relative to other literature reports