The catalytic performance of the superparamagnetic nanocatalyst Fe₃O₄@SiO₂@Sulfated boric acid as a green, recyclable, and acidic solid catalyst in the synthesis of chromeno[4,3,2‐de][1,6]naphthyridine derivatives has been studied. Chromeno[4,3,2‐de][1,6]naphthyridine derivatives via a pseudo four‐component reaction from aromatic aldehydes (1 mmol), malononitrile (2 mmol), and 2′‐hydroxyacetophenone in the presence of Fe₃O₄@SiO₂@Sulfated boric acid (0.004 g) as a nanocatalyst in 3 mL of water as a green solvent at 80°C has been synthesized. The advantages of this method are higher product yields in shorter reaction times, easy recyclability and reusability of the catalyst, and easy work‐up procedures. The nanocatalyst was reused at least six times. The nanocatalyst retained its stability in the reaction, and after reusability, it was separated easily from the reaction by an external magnet.

中文翻译：

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Fe3O4 @ SiO2 @硫酸化的硼酸作为超顺磁性和可循环利用的纳米催化剂辅助的5-氨基-2-芳基-3H-铬NO [4,3,2-de] [1,6]的一锅法假四组分合成。萘啶-4-腈衍生物

超顺磁性纳米催化剂Fe ₃ O ₄ @SiO ₂ @硫酸化硼酸作为绿色，可循环利用和酸性固体催化剂，在合成铬诺[4,3,2- de ] [1,6]萘啶衍生物中具有被研究了。在Fe ₃ O存在下，由芳香醛（1 mmol），丙二腈（2 mmol）和2'-羟基苯乙酮通过假四组分反应生成Chromeno [4,3,2- de ] [1,6]萘啶衍生物₄ @SiO ₂在80℃下，在3mL作为绿色溶剂的水中合成了作为纳米催化剂的硫酸化硼酸（0.004g）。该方法的优点是：在较短的反应时间内可以提高产品收率，催化剂的回收率和重复使用性易于操作，并且后处理程序也很容易。纳米催化剂被重复使用至少六次。纳米催化剂在反应中保持其稳定性，并且在可重复使用之后，其易于通过外部磁体与反应分离。