Application of the Immobilized Sulfonic Acid on the Magnetic Cobalt Ferrite Nanocatalyst (CoFe2O4/SiO2/SO3H) in the Synthesis of Organic Materials

Sulfuric acid as a homogeneous Bronsted acid catalyst is widely applied for the synthesis ofchemical compounds, but some drawbacks such as tedious workup, equipment corrosion, andcontamination of products restricted the use of this catalyst [1]. The heterogenization ofBronsted acids can solve these drawbacks and many solid supports such as magnetic nanoparticlesare good nominate for this purpose [2]. On the other hand, spirooxindoles are commonstructures in alkaloids skeleton which have privileged chemotypes for antiviral drug development[3]. In this study, chlorosulfonic acid was supported onto the CoFe2O4/SiO2 and theheterogeneous magnetic solid acid (CoFe2O4/SiO2/SO3H) was characterized and used for thesynthesis of spirooxindoles derivatives (Fig. 1). The results showed that the catalyst has excellentefficiency and the reusability and the products were synthesized at a short time (4 min)in green media (Water/EtOH 1:1) with high yield.