Glycosides from Muscaricomosum. 7. Structure of three novel muscarosides

Muscarosides D, E, and F, three new 27-norlanostane tetra-, penta-, and hexasaccharides, respectively, isolated from the bulbs of Muscaricomosum, were respectively shown to be (23S,24S)-3-O-{α-L-arabinopyranosyl(1→3)[β-D-apio-D-furanosyl(1→2)]-β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→6)-β-D-glucopyranosyl}-17,23-epoxy-3β,24,30,31-tetrahydroxy-27-nor-5α-lanost-8-ene 4, (23R)-3-O-{α-L-arabinofuranosyl(1→2)-α-L-arabinopyranosyl(1→3)[α-L-rhamnopyranosy(1→2)]-β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→6)-β-D-glucopyranosyl}-17,23-epoxy-3β,31-dihydroxy-27-nor-5α-lanost-8-en-15,24-dione 5, and (23S)-3-O-[β-D-apio-D-furanosyl(1→2)-β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→6)-β-D-glucopyranosyl]-17,23-epoxy-3β,31-dihydroxy-27-nor-5α-lanost-8-en-15,24-dione 6. The structural details were elucidated by a combination of fast-atom-bombardment mass spectroscopy, one- and two-dimensional nuclear magnatic resonance spectroscopy, and comparison to model compounds expressly synthesized.