. 2020 Apr 28;25(9):2058. doi: 10.3390/molecules25092058
© 2020 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.
Preparation of 3a–c and 4a–c derivatives.