In this study, poly(2‐ethyl‐2‐oxazoline) (PEtOx) immobilized on Fe₃O₄ nanoparticles (Fe₃O₄@SiO₂/PEtOx) has been constructed as a new, heterogeneous, efficient, and recyclable nanocatalyst. The prepared nanocatalyst was characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), powder X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDS) analysis, and vibrating‐sample magnetometer (VSM) techniques. Nanocatalyst was employed to synthesize benzo[b]xanthene‐triones and tetrahydrochromeno[2,3‐b]xanthene tetraones via one‐pot three‐ or pseudo–five‐component reaction between 2‐hydroxy‐1,4‐naphthoquinone or 2,5‐dihydroxy‐1,4‐benzoquinone, aldehyde, and dimedone or 1,3‐cyclohexanedione under reflux condition in ethanol. The catalyst could be easily separated and recycled several times without considerable loss of activity. Clean methodology, easy work‐up, mild reaction condition, short reaction time with good‐to‐excellent yields, and simple preparation of the catalyst are some advantages of the presented work.

中文翻译：

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Fe3O4 @ SiO2 / PEtOx作为新型，可磁循环利用和生态友好的纳米催化剂，通过三或假五组分反应合成苯并[b] x吨三酮和四氢铬基[2,3-b] x吨四酮

在这项研究中，已将固定在Fe ₃ O ₄纳米颗粒（Fe ₃ O ₄ @SiO ₂ / PEtOx）上的聚（2-乙基-2-恶唑啉）（PEtOx）构造为一种新型，多相，高效且可回收的纳米催化剂。制备的纳米催化剂通过傅里叶变换红外（FTIR），扫描电子显微镜（SEM），粉末X射线衍射（XRD），能量色散X射线光谱（EDS）分析和振动样品磁强计（VSM）技术进行表征。纳米催化剂被用来合成苯并[ b ]氧杂蒽酮和四氢色素[2,3- b氧杂蒽四酮通过在以下条件下的2-羟基-1,4-萘醌或2,5-二羟基-1,4-苯醌，醛和二甲酮或1,3-环己二酮之间的一锅三或假五组分反应在乙醇中的回流条件。该催化剂可以容易地分离并循环使用几次，而活性没有明显损失。清洁的方法，容易的后处理，温和的反应条件，较短的反应时间和良好至优异的收率，以及催化剂的简单制备是所提出的工作的一些优点。