1. Ominoxanthone—The First Xanthone Linearly Fused to a γ-Lactone from Cortinarius ominosus Bidaud Basidiomata. CASE- and DFT-Based Structure Elucidation.
- Author
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Trac, Alice, Issaad, Célia, Beniddir, Mehdi A., Bellanger, Jean-Michel, Gallard, Jean-François, Buevich, Alexei V., Elyashberg, Mikhail E., and Le Pogam, Pierre
- Subjects
CHEMICAL formulas ,NATURAL products ,XANTHONE ,MANGIFERIN ,WORKFLOW ,MUSHROOMS - Abstract
The UHPLC–HRMS analysis of Cortinarius ominosus basidiomata extract revealed that this mushroom accumulated elevated yields of an unreported specialized metabolite. The molecular formula of this unknown compound, C
17 H10 O8 , indicated that a challenging structure elucidation lay ahead, owing to its critically low H/C atom ratio. The structure of this new isolate, namely ominoxanthone (1), could not be solved from the interpretation of the usual set of 1D/2D NMR data that conveyed too limited information to afford a single, unambiguous structure. To remedy this, a Computer-Assisted Structure Elucidation (CASE) workflow was used to rank the different possible structure candidates consistent with our scarce spectroscopic data. DFT-based chemical shift calculations on a limited set of top-ranked structures further ascertained the determined structure for ominoxanthone. Although the determined scaffold of ominoxanthone is unprecedented as a natural product, a plausible biosynthetic scenario involving a precursor known from cortinariaceous sources and classical biogenetic reactions could be proposed. [ABSTRACT FROM AUTHOR]- Published
- 2023
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