. 2021 May 11;26(10):2840. doi: 10.3390/molecules26102840
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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 (https://creativecommons.org/licenses/by/4.0/).
Scheme 2.
Indirect preparation of a ring P-acid.