. 2021 Jun 30;26(13):3997. doi: 10.3390/molecules26133997
© 2021 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 (https://creativecommons.org/licenses/by/4.0/).
Scheme 4.
Synthesis of active molecules 5 and 6.