1,3-Disulfonic acid benzimidazolium chloride as an efficient and recyclable ionic liquid catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones/thiones

1,3-Disulfonic acid benzimidazolium chloride ionic liquid ([Dsbim]Cl) was prepared, characterized and applied as an efficient, homogeneous and recyclable catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones/thiones through the one-pot three-component condensation of aromatic aldehydes, urea/thiourea and ethyl acetoacetate under solvent-free conditions. The key advantages of this novel protocol are its short reaction time, high yields, mild and clean conditions, practical simplicity and its capacity for reuse several times without a noticeable decrease in catalytic activity.