Abstract
Bismuth trichloride has been found to be an efficient catalyst for the synthesis of 1,8-dioxo-octahydroxanthenes from aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione under solvent-free conditions in high yields.
Acknowledgments
The authors thank the Science Foundation from Hebei Normal University (L20061314), the Nature Science Foundation of Hebei Province (B2005000151) and the Natural Science Foundation of Hebei Education Department (2006318) for financial support of this work.
Notes
a Isolated yield
b compound 4 was formed in 32% yield
c compound 4 was formed in 90% yield.
a Isolated yield.