Cytosine nanoparticles have a large specific surface area (>1200 m2g-1) and can be prepared using an inexpensive procedure in water. In this work, we present an economical, simple, and environmentally friendly route for the preparation of a complex of copper on MCM-41 nanoparticles (Cu-Cytosine@MCM-41) as heterogeneous catalyst. This catalyst has been characterized by several techniques such as N2 adsorption–desorption isotherms, SEM, EDS, XRD, TGA, Ft-IR, and AAS techniques. Based on SEM images of Cu-Cytosine@MCM-41, the particles size of this catalyst were obtained in 80-120 nm of diameters. Cu-Cytosine@MCM-41 was applied as highly efficient and reusable nanocatalyst in multicomponent reactions such as synthesis of 5-substituted tetrazoles and pyranopyrazole derivatives. Tetrazoles and pyranopyrazoles have a wide range of biological activities such as antibacterial, antifungal, anticancer agents, anti-infammatory and insecticidal properties. This catalyst was reused for several times without loss of its catalytic activity. Heterogeneity and stability of Cu-Cytosine@MCM-41 were studied by hot filtration test and AAS analysis
