Introduction of a novel dicationic Bronsted acidic ionic liquid based on pyrazine and its application in the synthesis of xanthenediones and 3, 4-dihydropyrimidin-2(1H)-ones under solvent-free conditions

A novel dicationic Bronsted acidic ionic liquid based on pyrazine has been prepared and characterized by FTIR, H-1 NMR, C-13 NMR, MS, thermal gravimetric and differential thermal gravimetric analysis and also Hammett acidity function. The prepared dicationic ionic liquid is found to be an efficient and reusable catalyst for the synthesis of xanthenediones and 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. The merits of the developed procedure include novelty in terms of the ionic liquid, easy preparation of the ionic liquid, easy workup, reusability of the catalyst, high yield, short reaction time and absence of toxic organic solvent.