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Guignardic Acid, a Novel Type of Secondary Metabolite Produced by the Endophytic Fungus Guignardia sp.: Isolation, Structure Elucidation, and Asymmetric Synthesis
Author(s) -
RodriguesHeerklotz Katia F.,
Drandarov Konstantin,
Heerklotz Jörg,
Hesse Manfred,
Werner Christa
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20011219)84:12<3766::aid-hlca3766>3.0.co;2-z
Subject(s) - chemistry , metabolite , moiety , stereochemistry , oxidative deamination , phenylpyruvic acid , phenylalanine , organic chemistry , amino acid , biochemistry , enzyme
A UV‐guided fractionation of the AcOEt extract of the fermentation broth of Guignardia sp., an endophytic fungus from the leaves of the tropical tree Spondias mombin , resulted in the identification of the new metabolite (−)‐(2 S ,5 Z )‐2‐(1‐methylethyl)‐4‐oxo‐5‐(phenylmethylene)‐1,3‐dioxolane‐2‐carboxylic acid ( 1 ), isolated as NH salt 1a . The metabolite 1 was designated (−)‐( S )‐guignardic acid. This first member of a new class of natural compounds contains a dioxolanone moiety formed by fusion of 2‐oxo‐3‐phenylpropanoic acid (phenylpyruvic acid) and 3‐methyl‐2‐oxobutanoic acid (dimethylpyruvic acid), products of the oxidative deamination of phenylalanine and valine, respectively. The structure of 1a was deduced from spectral data (UV, IR, MS, 1 H‐ and 13 C‐NMR) and confirmed by asymmetric synthesis.