. 2021 Sep 16;26(18):5611. doi: 10.3390/molecules26185611
© 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/).
Figure 1.
Chemical structures of compounds 1–4.