13C-N.M.R. characterizations of the sarsasapogenin disaccharides,the filiferins a and b: 2-O-(β-d-xylopyranosyl)- and 2-O(β-d-glucopyranosyl)-β-d-galactopyranosides

Filiferin B is identical to timosaponin A-III, which had previously been shown to be 3-O-2-O-(β-d-glucopyranosyl)-β-d-galactopyranosyl]sarsasapogenin. A larger-scale isolation of filiferin B from the seeds of Yucca filifera led to the isolation of filiferin A, now shown to be 3-O-2-O-β-d-xylopyranosyl)-β-d-galactopyranosyl]-sarsasapogenin. The presence of the xylose residue was established by way of hydrolysis. 8-Methoxycarbonyloctyl 2-O-(β-d-glucopyranosyl)-β-d-galactopyranoside was synthesized to serve as a model for interpretation of the ¹³C-n.m.r. spectrum of filiferin B. The information thus gained, together with the ¹³C-n.m.r. spectra of other, simple model-compounds, permitted assignment of the structure for filiferin A. 8-Methoxycarbonyloctyl 2-O-(α-d-glucopyranosyl)-β-d-galactopyranoside was also synthesized.