Due to the biological activities and pharmaceutical versatilities, the chemistry and synthesis of quinoline derivatives have been widely investigated. They have been applied as antagonists, analgesic agents, 5HT3, NK-3 receptors, and also some natural products bearing these active compounds [1, 2]. On the other hand, ionic liquids (ILs) have found their influential roles as ubiquitous compounds for different applications such as catalyst, reagent and solvent systems and due to their capabilities in the domain of eco-compatible systems, the chemistry of them have been well documented [3]. Herein, we wish to report tributyl(3-sulfopropyl)phosphonium hydrogen sulfate as a task-specific catalyst for the synthesis of quinoline-4-carboxylic acids via anomeric based oxidation mechanisem.
