. 2018 May 5;23(5):1093. doi: 10.3390/molecules23051093
© 2018 by the authors.
Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Figure 1.
Structure of the selected precursors 1–4.