A rapid synthesis of quinoxalines by using Al2O3–ZrO2 as heterogeneous catalyst

Abstract

In this study, we present a highly efficient and environmentally benign protocol for synthesizing biologically important quinoxaline derivatives. The synthesis involves the reaction of 1,2-diamines with substituted phenacyl bromides or benzil, taking place at room temperature in N,N-dimethylformamide (DMF) solvent. The reaction is facilitated by a bifunctional heterogeneous catalyst composed of Al2O3–ZrO2 binary metal oxide. Our method offers numerous advantages, including excellent product yield, renewable catalytic conditions, minimal catalyst usage, safer chemistry, short reaction time, and a simple work-up procedure. To determine the chemical structure of the synthesized derivatives, we employed characterization techniques such as nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). Additionally, the Al2O3–ZrO2 catalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDAX), and thermogravimetric analysis (TGA).