Zr-guanine-MCM-41 catalyzed Tandem Knoevenagel– Michael Reactions MCM-41-supported nanoscale guanine bonded with Zr(IV) was prepared using sol-gel method and characterized by FT-IR, Raman, XRD, BET, TGA, EDX, ICP, AAS, X-Ray mapping, SEM and TEM techniques. This compound was employed as an efficient, chemoselectivity and green heterogeneous catalyst in order to prepare a series of benzo[a]benzo[6,7]chromeno[2,3‐c]phenazine and spiro[benzo[a]benzo[6,7]chromeno[2,3‐c] phenazine] derivatives by one-pot, four-component domino reaction from the 2-hydroxy-1,4- naphthoquinone, benzene-1,2-diamines, 2-hydroxy-1,4-naphthoquinone and carbonyl compounds in PEG, at 100°C and, also, Bis(pyrazolyl) methane derivatives using aldehydes and 3-Methyl-1- phenyl-5-pyrazolone in ethanol under reflux condition. Results indicated that all products were synthesized in short reaction times and high yields in the ranges 78–99%. The Zr-guanine-MCM41 can be recycled four runs without any significant loss of its catalytic activity. In addition, the stability of the catalyst was confirmed by metal leaching, heterogeneity tests, SEM and FT-IR techniques.
