. 2009 Aug 3;14(8):2857–2861. doi: 10.3390/molecules14082857
© 2009 by the authors;
licensee Molecular Diversity Preservation International, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).
Scheme 2.
Cyclization to xanthone 5.