3 NEW ELLAGIC ACID-DERIVATIVES FROM THE BARK OF ESCHWEILERA-CORIACEA FROM THE SURINAM RAIN-FOREST

Bioassay-guided fractionation of Eschweilera coriacea collected in the lowland wet forest of Suriname yielded the new but only weakly active ellagic acid derivative eschweilenol A (1) and the two new but inacti ve ellagic acid derivatives eschweilenol B (2) and eschweilenol C (3). The four known compounds, sucrose, ellagic acid, 3-O-galloylepigalloc atechin, and epigallocatechin, were also isolated. The structures of t he three new compounds were determined by spectrometric methods, prima rily from the HMQC, HMBC, NOESY, and ROESY NMR techniques, and chemica l methods, including methylation and triethylsilylation. The location of a hydroxyl group in one ellagic acid derivative was determined by a new technique involving an NOE correlation of the protons of a trieth ylsilyl derivative with a proton on a neighboring aromatic ring.