Microwave-Accelerated Facile Synthesis of 1 <i>H</i> -Pyrazolo[1,2- <i>b</i> ]Phthalazine-5,10-Dione Derivatives Catalyzed by WEMPA
Prashant B. Hiremath, Kantharaju Kamanna
Abstract
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, 1H-NMR, 13C-NMR and LC-MS.