Microwave-Accelerated Facile Synthesis of 1H-Pyrazolo[1,2-b]Phthalazine-5,10-Dione Derivatives Catalyzed by WEMPA

An efficient and rapid one-pot multicomponent synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones through condensation of aldehyde, malononitrile and phthalhydrazide catalyzed by agro-waste solvent catalyst-derived water extract of mango peel ash (WEMPA) under microwave irradiation is described. Further, the catalyst is prepared from agricultural waste and characterized for elemental composition by different techniques such as SEM-EDX, XRD and flame photometry. This green synthetic approach offers various advantages such as inexpensive, abundantly available source, shorter reaction time (6-8 min), good-to-excellent yield (83%-89%), simple workup and a sustainable alternative method to the existing protocols. All the synthesized compounds (4a-l) was confirmed by FT-IR,H-1-NMR,C-13-NMR and LC-MS.

Automated summary

This study describes an efficient and rapid one-pot multicomponent synthesis method for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones using an agro-waste solvent catalyst. The method offers advantages such as low cost, availability, short reaction time, high yield, and simple product separation.