One-pot synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,1 0-dione derivatives under solvent-free conditions

A series of 1H-pyrazolo[1,2-b]phthalazine-5,1 0-diones were obtained from aldehydes, phthalhydrazide and malononitrile in good to excellent yields at 80-100 degree C under solvent-free conditions by proceeding through a simple, mild and efficient procedure utilizing N,N,N',N'-tetrabromobenzene-1,3-disulfonamide [TBBDA] and poly(N-bromo-N-ethylbenzene-1,3-d isulfonamide) [PBBS] as catalysts.