Sulfonic acid-functionalized magnetic nanoparticles as a recyclable and eco-friendly catalyst for atom economical Michael addition reactions and bis indolyl methane synthesis

摘要

A modified sulfonic acid functionalized magnetic nanoparticle composite (Fe3O4@gamma Fe2O3-SO3H) is prepared by the use of ultrasonic irradiation. By this modification, the size of the nano-particles was reduced and the magnetization of the material was highly improved. This improvement drastically affected the efficiency and magnetic separation of the material as a catalyst. This new modified nanomagnetic compound was used as a highly efficient and recyclable catalyst for functionalization of indole derivatives via Michael addition and Friedel-Crafts alkylation reactions in entirely environmentally friendly media at room temperature. This modified magnetic material can be easily applied for large-scale operations producing the desired products in excellent yields in highly pure states.