Stereochemical Heterogeneity in Verongid Sponge Metabolites. Absolute Stereochemistry of (+)-Fistularin-3 and (+)-11- e p i -Fistularin-3 by Microscale LCMS-Marfey's Analysis

Department of Chemistry, University of California, Davis, 95616, USA.
Journal of Natural Products (Impact Factor: 3.8). 07/2005; 68(6):891-6. DOI: 10.1021/np050050n
Source: PubMed


The absolute configurations of fistularin-3, 11-epi-fistularin-3, and a related bis-oxazolidinone were determined by microscale hydrolysis followed by derivatization with 1-fluoro-2,4-dinitrophenyl-5-l-alaninamide. Samples of fistularin-3 from Verongid marine sponges collected in the Great Barrier Reef (Australia), Baía de Todos os Santos (Brazil), and the Key Largo, Florida (USA) varied in configuration at C11, a phenomenon that may be attributed to the involvement of stereochemically promiscuous hydroxylase enzymes. Variability in C11 configuration in fistularin-3 samples may have been overlooked in previously reported encounters due to the similarity of spectroscopic properties of fistularin-3 and 11-epi-fistularin-3 and their coelution under chromatographic conditions. Stereochemical heterogeneity at C11 in fistularin-3 samples suggests a possibility of a native biotransformation of suitable precursor in Verongid sponges by their associated microbial flora.

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