Zirconium tetrachloride as a highly efficient catalyst for the synthesis of xanthendione derivatives

Xanthene and its derivatives are known as an important class of heterocyclic compounds, and widely used as lecodyes, pH-sensitive fluorescent materials for visualization of biomoleculesand are utilized in laser technologiesdue to their photochemical and photophysical properties.They possess diverse biological and therapeutic propertiessuch as anti-inflammatory, anti-viraland anti-bacterial activities. These compounds are being utilized antagonists for paralyzing action of zoxazolamineandphotodynamic therapy1,2. Xanthendiones are important builing blocks in a number of natural products and have been used as versatile synthons because of the inherent reactivity of the inbuilt pyranring. For the synthesis of xanthendionederivatives, zirconium tetrachloridewas added to dimedone and different aromatic aldehydes in at 60 °C under solvent freecondition (Figure1).