Application of immobilized sulfonic acid on the cobalt ferrite magnetic nanocatalyst (CoFe2O4@SiO2@SO3H) in the synthesis of spirooxindoles

Abstract

Sulfonic acid immobilized on the surface of magnetically cobalt ferrite/silicate is a green, convenient, efficient and recyclable catalyst which can be applied in organic reactions ranges from lab to industry goals as a solid acid to achieve high yield products. After synthesizing ( CoFe2O4/SiO2/SO3H), it was also characterized by using different techniques such as FT-IR, XRD, EDX, VSM, TEM, SEM, TGA and so on which everyone approved presented structure. In this study, we are on to use this catalyst in a certain multicomponent reaction that is a common way to produce heterocycle compounds in order to synthesis spirooxindole derivatives which possess biological capabilities as anticancer and antimicrobial drugs. Hence, the three-component reaction of malononitrile, dimedone and isatin were performed in one pot under optimized situations of 80 °C temperature, reflux condition and water/ethanol (1:1) mixture as the solvent. Also, the present study shows unique advantages, such as simple synthesis of the catalyst, high magnetic properties, easy separation of catalyst with a permanent magnet, and the application of inexpensive and available precursors. At the end of the reaction, we gained the high yields of product at a short time that represents the high catalytic activity of the catalyst.