An effective one-pot, convenient process for the synthesis of 1-and 5-substituted 1H-tetrazoles from nitriles and amines is described using1,4-dihydroxyanthraquinone-copper(II) supported on Fe 3 O 4 @SiO 2 magnetic porous nanospheres as a novel recyclable catalyst. The application of this catalyst allows the synthesis of a variety of tetrazoles in good to excellent yields. The preparation of the magnetic nanocatalyst with core-shell structure is presented by using nano-Fe 3 O 4 as the core, tetraethoxysilane as the silica source and poly(vinyl alcohol) as the surfactant, and then Fe 3 O 4 @SiO 2 was coated with 1,4-dihydroxyanthraquinonecopper(II) nanoparticles. The new catalyst was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, thermogravimetric analysis, vibration sample magnetometry, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption isotherm analysis and inductively coupled plasma analysis. This new procedure offers several advantages such as short reaction times, excellent yields, operational simplicity, practicability and applicability to various substrates and absence of any tedious workup or purification. In addition, the excellent catalytic performance, thermal stability and separation of the catalyst make it a good heterogeneous system and a useful alternative to other heterogeneous catalysts. Also, the catalyst could be magnetically separated and reused six times without significant loss of catalytic activity.

In this study, a novel heterogeneous palladium catalyst was synthesized by anchoring palladium onto ethylenediaminetetraacetic acid (EDTA)‐coated Fe3O4@SiO2 magnetic nanocomposite and used for the Suzuki and Sonogashira cross‐coupling reactions. The properties of the magnetic catalyst were characterized by FT‐IR, XRD, TEM, FE‐SEM, DLS EDX, XPS, N2 adsorption‐desorption isotherm analysis, TGA, VSM, elemental analysis and the loading level of Pd in catalyst was measured to be 0.51 mmol/g by ICP. The catalyst was used in Suzuki cross‐coupling reactions of various aryl halides, including less reactive chlorobenzenes with phenylboronic acid without any additive or ligand under green conditions. Furthermore, we have reported this recyclable catalytic system for Sonogashira cross‐coupling reactions of various aryl halides (I, Br, Cl) under copper and ligand‐free conditions in the presence of DMF/H2O (1:2/v:v) as a solvent. The magnetic catalyst could also be separated by an external magnet and reused six times without any significant loss of activity.

1,4-Dihydroxyanthraquinone–copper(ii) supported on superparamagnetic Fe3O4@SiO2 catalyst was employed for the N-arylation of nitrogen heterocycles and alkylamines.

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An efficient method for the preparation of acylals from different aldehydes in the presence of silica sulfuric acid and acetic anhydride under solvent-free conditions is reported.