B-norsteroids from Hymenoscyphus pseudoalbidus

Autor: Pierre F. Andersson, Stina Bengtsson, Jan Stenlid, Anders Broberg
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: Molecules, Vol 17, Iss 7, Pp 7769-7781 (2012)
Druh dokumentu: article
ISSN: 1420-3049
DOI: 10.3390/molecules17077769
Popis: Two viridin-related B-norsteroids, B-norviridiol lactone (1) and B-norviridin enol (2), both possessing distinct unprecedented carbon skeletons, were isolated from a liquid culture of the ash dieback-causing fungus Hymenoscyphus pseudoalbidus. Compound 2 was found to degrade to a third B-norsteroidal compound, 1β-hydroxy-2α-hydro-asterogynin A (3), which was later detected in the original culture. The proposed structure of 1 is, regarding connectivity, identical to the original erroneous structure for TAEMC161, which was later reassigned as viridiol. Compound 2 showed an unprecedented 1H-13C HMBC correlation through an intramolecular hydrogen bond. The five-membered B-ring of compounds 1–3 was proposed to be formed by a benzilic acid rearrangement. The known compound asterogynin A was found to be formed from 3 by a β-elimination of water. All compounds were characterized by NMR spectroscopy, LC-HRMS and polarimetry.
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