The synthesized Fe3O4@l-arginine showed strong catalytic performance in the one-pot synthesis of spiropyranopyrazoles via the reactions of hydrazines, β-keto esters, isatins, and malononitrile or ethyl cyanoacetate under solvent-free conditions. The biologically active heterocyclic compounds including spiropyranopyrazole derivatives were efficiently synthesized in short reaction times and excellent yields in the presence of Fe3O4/l-arginine at room temperature. The highlighted features of the Fe3O4@l-arginine nanocomposite are highly stable, easy to separate, low loading, cost-effective with easy preparation and reusability of the catalyst. The heterogeneous nanocomposite was fully characterized by SEM, EDX, FT-IR, XRD and TEM analysis.

中文翻译：

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使用 Fe3O4@l-精氨酸作为稳健且可重复使用的催化剂绿色合成螺[二氢吲哚-3,4′-吡喃并[2,3-c]吡唑]

合成的Fe3O4@l-精氨酸在无溶剂条件下通过肼、β-酮酯、靛红和丙二腈或氰乙酸乙酯的一锅法合成螺吡喃吡唑中表现出很强的催化性能。在 Fe3O4/l-精氨酸存在下，在室温下，可以在短反应时间内有效合成包括螺吡喃吡唑衍生物在内的生物活性杂环化合物，并获得优异的产率。Fe3O4@l-精氨酸纳米复合材料的突出特点是高度稳定、易于分离、负载量低、成本效益高、易于制备和催化剂可重复使用。通过 SEM、EDX、FT-IR、XRD 和 TEM 分析对异质纳米复合材料进行了全面表征。