Diethylene glycol-bis(3-methylimidazolium) dihydroxide [DiEG(mim)2][OH]2 was prepared by the reaction
between sodium hydroxide and diethylene glycol-bis(3-methylimidazolium) dibromide in aqueous
ethanol at room temperature. This solid, quaternized ionic liquid was employed as a recyclable catalyst
for the synthesis of 4H-pyrane derivatives in high yields from the three-component condensation reaction
of malononitrile, aromatic aldehydes, and 1,3-dicarbonyls in water at room temperature. In addition,
spiropyrane derivatives were synthesized from the reaction of isatin, malononitrile, and 1,3-dicarbonyls
in water at reflux. The dicationic ionic liquid showed the same efficiency when used in consecutive
reactions.