Polyethylene glycol-bis (N-methylimidazolium) dihydroxide as an efficient and recyclable basic phase-transfer catalyst for the synthesis of 4H-pyran derivatives in aqueous media

Abstract

Polyethylene glycol-bis (N-methylimidazolium) dihydroxide, [PEG(mim)2][OH]2, was prepared from the reaction of polyethylene glycol-bis (N-methylimidazolium) dibromide and sodium hydroxide in aqueous media at ambient temperature. The obtained solid was used as a novel, green, recyclable and efficient basic phase-transfer catalyst in the synthesis of 2-amino-3-cyano-4H-pyrans via the one-pot three-component condensation reaction of aromatic aldehydes, malononitrile and 1,3-dicarbonyl compounds in water at room temperature. The reactions without any basic reactants and in the presence of trace amounts of the catalyst gave the corresponding products with high yields in short reaction times. The phase-transfer catalyst could be successfully reused without the significant decrease in its activity.