Glycerol: A Promising Benign Solvent for Catalyst-free One-pot Multi-component Synthesis of 1H-Pyrozolo[1,2-b]phthalazine-5,10-diones and 2H-Indazolo[2,1-b]phthalazine-triones Under Controlled Microwaves Irradiation

A simple green and efficient one-pot multi-component synthesis of 1H-pyrozolo[1,2-b]phthalazine-5,10-diones and 2H-indazolo[2,1-b]phthalazine-triones has been developed utilizing one-pot multi-component reaction of aromatic aldehydes, active methylene reagents, phthalic anhydride, and hydrazine hydrate or alternatively phthalhydrazide in glycerol without catalyst under controlled microwave heating. The current synthetic protocol offers several advantages such as excellent yields, high EcoScale and atom economy, simple working up reactants and products, and the absence of hazardous catalysts or solvents.