Fe3O4@SiO2@sulfated boric acid as superparamagnetic and recyclable nanocatalyst-assisted, one-pot, pseudo four-component synthesis of 5-amino-2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitrile derivatives

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 (0.004g) as a nanocatalyst in 3 mL of water as a green solvent at 80 degrees 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.