Fe3O4@TiO2@O2PO2(CH2)NHSO3H as a novel nano magnetic catalyst: Application at the preparation of 2-amino-4,6-diphenylnicotinonitriles via anomeric based oxidation

Nowadays, heterogeneous catalysis, due to the high capability in recycling and reutilizability, has surpassed the homogeneous catalytic systems, despite their benefits such as high activity and selectivity. On the other hand, magnetically recoverable catalysts (MRCs) have emerged as a potent and persuading option from the point of green chemistry view due to the meaningful merits like excellent catalytic performance and easy separation and recovery from the reaction mixture. Therefore, utilizing of the magnetic nano particles (MNPs) as suitable alternative support for the catalyst-supported materials in the designing and synthesis of magnetically recoverable heterogeneous catalysts are valuable as they are widely explored [1,2]. A new, green and reusable nano magnetic heterogeneous catalyst namely Fe3O4@TiO2@O2PO2(CH2)NHSO3Hwas synthesized and fully characterized using suitable technics. Afterwards, the promoter applicability of the constructed heterogeneous core-shell catalyst was successfully explored at the synthesis of 2-amino-4,6-diphenylnicotinonitrile derivatives upon the reaction of a good range of aromatic aldehydes, acetophenone derivatives, malononitrile and ammonium acetate. The desired products were obtained with good to high yields in short reaction times under solvent free conditions. The suggested mechanism offers an anomeric based oxidation route to the products in the final step of the synthetic pathway (Figure 1) [3].