. 2014 Oct 28;19(11):17256–17278. doi: 10.3390/molecules191117256
© 2014 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 license (http://creativecommons.org/licenses/by/4.0/).
Scheme 1.
Synthesis of compounds a1–20 and b1–42.