Green synthesis of dipyrromethanes in aqueous media catalyzed by SO3H-functionalized ionic liquid

Abstract

A mild, efficient and metal-free method was described for the green synthesis of dipyrromethanes from aldehydes and unsubstituted pyrrole catalyzed by SO₃H-functionalized ionic liquids (SO₃H-ILs) in aqueous media at room temperature. Notably, SO₃H-ILs, 1-butylsulfonic-3-methylimidazolium hydrogen sulfate ([bsmim][HSO₄]) was the most efficient catalyst for moderate to good yields of the corresponding desired products.