Tannic Acid-Cu-modified Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2@TA-Cu NPs): New recyclable magnetic catalyst for the three-component synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines

An effectual encapsulation-functionalization procedure for preparing high-activity magnetic Fe3O4@SiO2@Tannic Acid-Cu (Fe3O4@SiO2@TA-Cu) nanocomposite was described. Tannic acid-Cu complexes were uniformly protected on the surface of Fe3O4@SiO2 nanoparticles. The newly prepared catalyst was characterized by XRD, FT-IR, SEM, and EDX. The obtained nanocomposites showed excellent catalytic performance and good stability for the one-pot synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines via three-component condensations of aldehydes, malononitrile, and thiophenols in water. The catalyst was separated by a magnet and reused at least five times without remarkable degradation in the performance. The desired products were prepared in high yields by an easy workup procedure with this protocol.

Automated summary

An effective encapsulation-functionalization method was employed to prepare a high-activity magnetic nanocomposite Fe3O4@SiO2@TA-Cu. The surface of Fe3O4@SiO2 nanoparticles was uniformly protected by tannic acid-Cu complexes. The obtained nanocomposites exhibited excellent catalytic performance and stability for the synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines via three-component condensations.