Green synthesis of 5-benzylidene rhodanine derivatives catalyzed by 1-butyl-3-methyl imidazolium hydroxide in water

Article abstract of DOI:10.1007/s00706-008-0871-y

A basic functionalized ionic liquid, 1-butyl-3-methyl imidazolium hydroxide ([bmim][OH]), catalyzed the Knoevenagel condensation of rhodanine with aromatic aldehydes. It proceeded smoothly in water to afford the 5-benzylidene rhodamine derivatives in high yields at room temperature. This new method offers several advantages, such as excellent yields, short reaction times, and simple procedure. The catalyst can be reused at least 5 times without significant loss of activity.