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Abstract
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The art of synthesis targets molecules via domino reactions including sequentially named reactions have attracted great interest. In this regard, Knoevenagel condensation–Michael addition is one of the most popular sequencies which was utilized to synthesize a wide variety of Functionalized organic molecules 1. N-containing heterocycles e.g. bis(pyrazolyl)methanes are a series of the most important compounds which could be prepared by this sequencie 2. When the catalysts are present, these compounds with the functionalized aromatic rings, which have fascinated much interest because of their diverse pharmacological and therapeutic properties, can be generated from this reactions 1–3. In this work, the Silica sulfuric acid bonded Hercynite MNPs was designed and synthesized by Zolfigol’s method as a novel magnetic solid acid catalyst. Then it was introduced as a new and efficient magnetically recoverable nanocatalyst for the synthesize bis(pyrazolyl)methanes in good to excellent yields via the following protocols: (i) the one-pot pseudo five-component reaction of phenylhydrazine (2 equivalents), ethyl acetoacetate (2 equivalents) and arylaldehydes (1 equivalent), and (ii) the one-pot pseudo three-component reaction of 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐one (2 equivalents) with arylaldehydes (1 equivalent). In addition, the magnetic and heterogeneous nature allows easy separation of the catalyst from the reaction mixtures by magnetic decantation and the catalyst could be reused at least 5 catalytic cycles for both of the mentioned reactions without obvious drop of initial activity.
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