In the present study, KIT-6@SMTU@Ni was successfully synthesized using stabilization of a new Ni complex on mesoporous KIT-6 as a novel and green heterogeneous catalyst. The obtained KIT-6@SMTU@Ni catalyst was characterized by FT-IR, BET, SEM, XRD, AAS, EDS and TGA techniques. After full characterization, KIT-6@SMTU@Ni catalyst was successfully investigated in the synthesis of 5-substituted tetrazoles and pyranopyrazoles. Tetrazoles were synthesized from [3 + 2] cycloaddition of sodium azide (NaN3) to the corresponding nitriles. Also pyranopyrazoles were prepared by the condensation reaction of benzaldehyde derivatives with malononitrile, hydrazine hydrate and ethyl acetoacetate. Because, tetrazole derivatives have been used as antiviral, anti-proliferative, anti-inflammatory, antibacterial, antifungal and anticancer agents [1-3]. Also, pyranopyrazoles composed of pyrazole and pyran rings, including significant biological activity such as anticancer, antimicrobial, anti-inflammatory, CHK-1 kinase inhibitor, and anti-viral [4-6]. Use of green medium, simple method, easy separation and workup, excellent reusability of the nanocatalyst, short reaction times, and high yields are outstanding advantages of these methodologies. Moreover, this catalyst can be easily recovered from the reaction mixture by simple filtration and reused for several consecutive cycles without noticeable change in its catalytic activity.
