Preparation of tetramethylguanidine-functionalized nano size γ-Al2O3 as a catalyst for the four-component synthesis of pyrazolopyranopyrimidine derivatives

Nanocatalysis is a rapidly growing field which involves the use of nanomaterials as catalysts for a variety of chemical reactions. Oxide nanoparticles can exhibit unique physical and chemical properties due to their limited size and a high density of corner or edge surface sites [1]. One of the important methaloxaids is aluminum oxide and among various structures for alumina, γ-alumina is one of the extremely important nano sized materials. It is used as structural composites for spacecraft, and abrasive and thermal wear coatings. γ-Alumina is thermody-namically more stable than the other relatives [2].At present study a durable nano sized γ-Al2O3 functionalized by 1,1,3,3-tetramethylguanidine(TMG) was successfully prepared by the hydrothermal method from aluminum nitrate nonahydrate (Al2(NO3)3.9H2O). The particle size of this catalyst was established by using SEM imaging studyto be in the range of 19 -40 nm. The catalyst was also characterized by various techniques including FT-IR, XRD, TGA and surface area analysis.The activity of synthesized catalyst was tested in the four-component synthesis of pyrazolopyranopyrimidine derivatives in H2O, which showed high catalytic activity, producing the desired products in reduced reaction times and excellent yields (90-98%).