Facile and efficient synthesis of pyrimido[1,2-a]benzimidazole and tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-one derivatives using Brönsted acidic ionic liquid supported on rice husk ash (RHA-[pmim]HSO4)

In this work, a green and efficient procedure has been reported for the synthesis of pyrimido[1,2- a ]benzimidazole and tetrahydrobenzimidazo[2,1- b ]quinazolin-1(2 H )-one derivatives using Brönsted acidic ionic liquid supported on rice husk ash (RHA-[pmim]HSO 4 ) as the catalyst. These reactions were performed at 100 °C under solvent-free conditions with high yields in very short reaction times.