. 2019 Nov 2;8(4):210. doi: 10.3390/antibiotics8040210
© 2019 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.
Formation of target compounds 3a-k and 4a-k.