One-pot efficient green synthesis of 1,4-dihydro-quinoxaline-2,3-dione derivatives

An efficient synthesis of the potential pharmacophore 1,4-dihydro-quinoxaline-2,3-dione (1) has been achieved in a one-pot reaction at room temperature from substituted o-phenylene diamine and oxalic acid under solvent-free conditions by a simple grinding method with unsurpassed atom economy. Thermal and powder X-ray diffraction analysis was carried out for some hydrated crystals.