Synthesis and Application of 3,6-Diphenylpyrazin-2,5-dione as an Efficient Ligand in Heck Reaction

3,6-Diphenylpyrazin-2,5-dione was prepared in two steps from reaction of phenylglyoxal monohydrate with ammonium acetate in water at room temperature, followed by subjecting with hydroxyl amine hydrochloride in the presence of NaOH in a mixture of EtOH/water under reflux conditions, and used as an efficient ligand in palladium catalyzed Heck reaction between aryl halides and various alkenes. The products were obtained in good to high yields.In addition to FT-IR and NMR, the structure of the ligand was also confirmed by single crystal X-ray crystallography. Easy preparation, inexpensiveness, and stability in air and moisture are the main advantageous of this ligand.