An AlFe2O4@SiO2–SO3H innovative nanocatalyst: a sustainable approach for the A3 coupling reaction in a DES for 2-thioarylbenzoazoles†
Abstract
The A3 coupling reaction, which facilitates the synthesis of 2-thioarylbenzoazoles, represents a significant transformation in organic chemistry with implications in drug discovery and materials science. In this study, we introduce a novel nanocatalyst, AlFe2O4@SiO2–SO3H, designed to enhance the efficiency and sustainability of this reaction. The catalyst is synthesized by functionalizing aluminum ferrite (AlFe2O4) with chlorosulfonic acid (Cl–SO3H), promoting its role as an effective acid catalyst. Utilizing deep eutectic solvents (DESs) as a green reaction medium further contributes to the sustainability of the process by providing a biodegradable and non-toxic environment. Optimization studies were conducted to determine the optimal reaction conditions, including catalyst loading, temperature, and solvent composition. Characterization of the nanocatalyst was performed using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) to confirm successful synthesis and functionalization. The AlFe2O4@SiO2–SO3H nanocatalyst exhibited excellent catalytic activity, resulting in high yields of 2-thioarylbenzoazoles under mild conditions while allowing for easy recovery and reuse without significant loss of activity. This work demonstrates the potential of AlFe2O4@SiO2–SO3H as a sustainable catalytic system for A3 coupling reactions, contributing to the development of environmentally friendly methodologies in organic synthesis.