Hercynite@SiO2-APTS-Proline as a Novel Magnetic Nanocatalyst for the Regioselective Synthesis of New Spiro[indoline-3,5'-pyrido-pyrimidine/dipyrimidine] Derivatives

Hercynite (FeAl2O4) magnetic nano particle (MNP) was prepared by a chemical coprecipitation process and the surface of its functionalized with amino propyl tetramethyl Silan (APTS) groups. Reaction of synthesized Hercynite@SiO2-APTS with proline was obtained Hercynite@APTS-Proline as a new nanoparticle. The structure and composition of the synthesized Hercynite@APTS-Proline characterized by FT-IR, XRD, EDX, SEM, TEM, TGA and VSM techniques. The catalytic activity of prepared Hercynite@APTS-Proline was used for the synthesis of spiro [indoline-3,5'- pyrido[2,3-d] pyrimidine] and spiro[indoline-3,5'-pyrido[2,3-d:6,5-d']dipyrimidine derivatives and the results show that its catalytic activity is better than other catalysts used. In addition, the synthesized catalyst can be easily separated and reused up to 5 times without any noticeable change in the reaction yield. Highlights ► Hercynite surface was modified by amino propyl tetramethyl silan (APTS) and proline ► A novel organic/inorganic nanocatalyst, Hercynite@APTS-Proline, was synthesized. ►Structure of nanocatalyst was confirmed by FT-IR, XRD, SEM and TEM methods. ► Nanocatalyst evaluated for synthesis of spiro[indoline-3,5'-pyrido-pyrimidine] derivatives ► Regioselectivity, stability and reusability are advantages of this catalyst.