. 2020 Feb 26;25(5):1051. doi: 10.3390/molecules25051051
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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/).
Scheme 3.
Plausible production mechanism of 9 from 2.