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Published on: November 9, 2019
Two ambuic acid dimers derived from homo-endo Diels-Alder reaction from Pestalotiopsis versicolor
Dan-Yi Li1, Xiao-Ling Zhang1, Zhan-Lin Li2
1School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Benxi 117004, China.
Abstract:
Two new dimers of ambuic acid, pestaloversicoloric acids A (1) and B (2), and a known derivative, 13(S)-hydroxyambuic acid (3), were isolated from the static fermentation product of Pestalotiopsis versicolor. The structural identification was accomplished via analyses on the data of HR-MS, 1 D and 2 D NMR, and ECD. Different from the well-known exo-type dimer, torreyanic acid, compounds 1 and 2 represent the first example of endo-type product derived from the intermolecular Diels-Alder reaction of two molecules of ambuic acid derivative with the identical absolute stereochemistry.
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