Nano-ZnO: an efficient and reusable catalyst for one-pot synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and pyrazolo[1,2-a][1,2,4]triazole-1,3-diones

The catalytic activity of nano-structured ZnO has been explored in the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and pyrazolo[1,2-a][1,2,4]triazole-1,3-dione derivatives via a three-component coupling reaction between aromatic aldehydes, malononitrile, and phthalhydrazides or 4-arylurazoles, respectively. High yield, low reaction times, non-toxicity and recyclability of the catalyst, and easy work-up are the main merits of this protocol.