Xanthones are tricyclic aromatic compounds that have multiple pharmacological uses due to their anti-tumor, antioxidant, anti-inflammatory, anti-bacterial, and potentially chemopreventive properties. The target of this research was to optimize a two-step synthesis of 3,6-dimethoxyxanthone (3) from 2,2’,4,4’-tetrahydroxy-benzophenone (1) via microwave-assisted (200 °C, 30-40 min., 150 W) sodium acetate-catalyzed annulation. The product, 3,6-dihydroxyxanthone (2), was then methylated to (3) using dimethyl sulfate (DMS) and sodium carbonate in acetone at reflux. The product yields were 93% (>99% purity) for (2) and 94% (>99% purity) for (3). Characterization was accomplished using 1H NMR, FTIR, melting point, TLC, HPLC, and GCMS. The product (3) was made available for additional screening and research, such as synthesizing dyes like fluorescein and its derivatives.
Knisely, Sarah E.; Rosario, Faith R.; Gebeyehu, Salem F.; Heiple, Paige E.; and Lee, Robert E. Sr
"3,6-dimethoxyxanthone from 2,2’,4,4’- tetrahydroxy-benzophenone via Microwave-Assisted Annulation,"
Journal of the South Carolina Academy of Science: Vol. 20:
2, Article 6.
Available at: https://scholarcommons.sc.edu/jscas/vol20/iss2/6