Introduction of benzimidazole-based ionic liquid as an efficient and reusable catalyst for the preparation of 1,8-dioxo xanthene derivatives

Xanthenes are biologically important drug intermediates for the synthesis of compounds having antibacterial, anti-inflammatory and antiviral activities [1]. Also,they were used as dyes in laser technologies, and in fluorescent materials for visualization of biomolecules. Because of these significant features there has been a continuous interest in the synthesis of these types of compounds and consequently numerous approaches have been reported for their synthesis [2]. Ionic liquids have received considerable interest as eco-friendly solvents, catalysts and reagents in organic synthesis because of their unique properties, such as low volatility, non-flammability, high thermal stability, negligible vapor pressure and ability to dissolve a wide range of materials [3]. In this work, a dicationic ionic liquid based on benzimidazole is simply prepared andafter is used for the promotion of the synthesis of 1,8-dioxoxanthene derivatives. The main advantage for using this catalyst are ease of separation of the catalyst, highyields of achived products during low reaction times.