In recent years, the development of environmentally benign catalysts and conditions has been one of the most important goals in the synthesis of widely used organic compounds. Magnetic nanoparticles (MNPs) are promising materials for researchers due to their strong magnetic properties, small size, high surface area, low-cost synthesis and biocompatibility. MNPs have been used in a broad array of applications such as catalysis, drug delivery, magnetic resonance imaging,8 sensors,9 nonlinear optics,and gene therapy. Furthermore, Fe3O4 nanoparticles enable encapsulation or immobilization of molecules such as dendrimers, proteins, and enzymes. Dendrimers are size- and shape-controlled macromolecules consisting of branches connected to a central core. Dendrimers immobilized on magnetic nanoparticles have been investigated intensively by our group and by other groups and have been used in several applications. These catalytic materials are highly efficient in terms of reactivity and selectivity and are easily recyclable. Multicomponent reactions (MCRs) have become powerful tools in organic, combinatorial and medicinal chemistry, and have attracted much attention from synthetic organic chemists because they can form complex molecules with a diverse range of functionality from readily available starting materials. We now describe a method based on combining the features of magnetic nanoparticles and dendrimers. The greater selectivity, large surface-to volume ratios, enhanced reaction rates, simple workup (using an external magnet) and recyclability of the catalyst are features that make magnetic Fe3O4@SiO2 core–shell nanoparticles functionalized with sulfamic acid polyamidoamine (PAMAM) dendrimer [Fe3O4@SiO2@PAMAM(G2)- SO3H] an attractive alternative heterogeneous catalyst. The silica coating can prevent aggregation and improve the properties of magnetic nanoparticles due to its biocompatibility, inertness, and chemical stability. We have demonstrated this by growing a pol
