Stilbene glycosides from Guibourtia coleosperma: determination of glycosidic connectivities by homonuclear nuclear Overhauser effect difference spectroscopy

Abstract

Two novel stilbene glycosides, 3,4′-dimethoxy- and 3,3′-dihydroxy-4′-methoxy-5-[O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyloxy]stilbene, have been obtained from Guibourtia coleosperma. Connectivities of glycosidic moieties in these and other mono- and bio-sides have been established by ¹H n.m.r. nuclear Overhauser effect difference spectroscopy. Such an approach may prove useful in cases where alternative methods towards achieving the same goal are hampered by limited sample quantitites.