Silica Ammonium Acetate(SiO2-NH4OAc) Catalyzed Facial Synthesis of Dihydropyrazolo[4',3':5,6]Pyrano[2,3-d]Pyrimidine-5,7-Diones

Abstract Silica ammonium acetate (SiO2-NH4OAc) was applied as an inexpensive, practical and heterogeneous catalyst for the preparation of new and known dihydropyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidine-5,7-diones via one-pot four-component reaction of hydrazine hydrate, ethyl acetoacetate aldehydes and barbituric acid/dimethyl barbituric acid under solvent-free conditions. Silica supported ammonium acetate (SiO2-NH4OAc) was prepared according to easy procedure under ambient condition. After completion of the reaction, the catalyst was separated by filtration and reused. So, recycling system, simple work-up, using non-toxic materials, excellent yields and short reaction times makes our research green and convenient for preparation of these classes of organic compounds.