STRUCTURE CHARACTERIZATION BY 2-DIMENSIONAL NMR-SPECTROSCOPY, OF 2 MARINE TRITERPENE OLIGOGLYCOSIDES FROM A PACIFIC SPONGE OF THE GENUS ERYLUS

The isolation and characterization of two novel triterpene glycosides from a sponge of the genus Erylus, collected at a depth of 500 m in the South of New Caledonia, are described. The structures are characterized by the presence of a branched oligosaccharide chain, composed of three (1) and four (2) D-galactopyranose units, respectively. Analysis of the oligosaccaride structures was achieved by {H-1, H-1} correlation spectroscopy, two-dimensional homonuclear Hartmann-Hahn, and H-1-detected {H-1, C-13} one bond (HMQC) and multiple-bond (HMBC) shift correlation NMR experiments. The novel Ianostane derived aglycone features a rare 14-carboxyl group and a 24-methylene, 25-methyl side chain.