. 2017 Dec 18;33(1):199–209. doi: 10.1080/14756366.2017.1407926
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This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Scheme 2.
Synthesis of compounds 5a,b–9a,b.