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Aminotenuazonic Acid: Isolation, Structure Elucidation, Total Synthesis and Herbicidal Activity of a New Tetramic Acid from Fruiting Bodies of Laccaria Species
Author(s) -
Schrey Hedda,
Backenköhler Jana,
Kogler Herbert,
Plaumann Markus,
Spiteller Peter
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901405
Subject(s) - total synthesis , chemistry , stereochemistry , botany , organic chemistry , biology
(5 S ,6 S )‐Aminotenuazonic acid, a new 3‐acyltetramic acid, related to the well‐known mycotoxin tenuazonic acid has been isolated from fruiting bodies of Laccaria bicolor . Its structure was mostly established by analysis of its 2D NMR and HR‐(+)‐ESI‐MS spectra. A total synthesis starting from N ‐Boc‐ l ‐isoleucine gave (5 S ,6 S )‐aminotenuazonic acid in 8 % yield over nine steps (67 % de ). The key steps of the total synthesis are a light‐initiated Hofmann–Löffler–Freytag radical chain reaction and a Dieckmann cyclisation. The relative and absolute configurations of the natural product were determined by comparison of its NMR and CD spectra with those of the corresponding enantiopure synthetic compounds. Metabolic profiling of crude extracts of different mushrooms showed that aminotenuazonic acid is present in all four of the investigated Laccaria species. Aminotenuazonic acid shows phytotoxic activities against the root and shoot growth of Lepidium sativum , Pinus sylvestris and Arabidopsis thaliana comparable to those of tenuazonic acid.