Gold-decorated carbon material for enhanced catalytic performance of cyclization/oxidation of 2-aminophenol, 2-aminothiophenol, and 2-aminoaniline with aromatic aldehydes

In this study, a three-step process for the synthesis of gold nanoparticles supported on amorphous carbon (Au-Ac) using readily available chemicals has been developed. The characterization and properties of the resulting Au-AC catalyst were investigated using advanced analytical techniques, including FT-IR, Raman spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDX). This is the first time the Au-AC has been applied as a catalyst in the synthesis of 2-arylbenzo[d]oxazoles/2-arylbenzo[d]thiazoles/1-benzyl-2-arylbenzo[d]imidazoles from 2-aminophenol/2-aminothiophenol/2-aminoaniline and aldehydes. The catalyst facilitates the process of cyclization and oxidation through the Au active sites. The successful synthesis of derivatives of 2-phenylbenzo[d]oxazole, 2-phenylbenzo[d]thiazole and 1-benzyl-2-arylbenzo[d]imidazoles was achieved by employing optimal reaction conditions, which included the use of a 30 mg Au-AC catalyst and 100 mg of [Emim]Cl at 110 °C for 24 h.