. 2017 Mar 27;22(4):507. doi: 10.3390/molecules22040507
© 2017 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/).
Scheme 1.
Synthesis route to target compounds 5a–5ad.