Tannic acid: An efficient catalyst for one-pot synthesis of xanthene derivatives under solvent-free conditions

The synthesis of xanthenes is important in organic synthesis because of their wide range of biological and pharmaceutical properties, such as agricultural bactericide activity, anti-inflammatory and antiviral and antibacterial activity. They have also been used in laser technology, used as leuco-dye and fluorescent material for visualization of biomolecules and in laser technologies.1-5 In recent year, Tannic acid has received considerable attention as an efficient catalyst for various organic transformations such as synthesis of imidazole derivatives, 1-amidoalkyl-2-naphthols and synthesis of benzodiepines derivatives.6 In continuation of our interest in the synthesis of heterocyclic compound7 we report the simple and efficient procedure for one pot synthesis of xanthene derivatives using tannic acid as catalyst in a solvent free reaction (Scheme 1).