1H and 13C NMR assignments for two new xanthones from the endophytic fungus Xylaria sp FRR 5657

The complete H-1 and C-13 NMR assignments are reported for the new natural products, 7-hydroxy-3-(hydroxymethyl)-1-methoxy-9H-xanthen-9-one (1) and 2,5-dihydroxy-8-methoxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid (2). Both of these secondary metabolites were isolated from the fermentation culture of the endophytic fungus Xylaria sp. FRR 5657. 1D and 21D NMR experiments that included H-1, gCOSY, gHSQC and gHMBC were used for the determination of the structure and assignment of these xanthones. Copyright (c) 2006 John Wiley & Sons, Ltd.