One-pot four-component synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives

The synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives by NiCl2-catalyzed novel one-pot four-component condensation reaction of phthalimide, hydrazine, malononitrile (or ethyl cyanoacetate), and aromatic aldehydes was reported. This work provides a simple, efficient, and eco-friendly method for the construction of pyrazolo[1,2-b]phalazine-5,10-dione derivatives.