. 2015 Nov 5;20(11):19947–19957. doi: 10.3390/molecules201119660
© 2015 by the authors.
Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
Figure 1.
Chemical structures of 1–23.