Glycosphingolipid

MELTING POINT	:
BOILING POINT	:
REFRACTIVE INDEX	:
OPTICAL ROTATION	:
DENSITY	:
SOLUBILITY	:

UV SPECTRA	:
IR SPECTRA	:
NMR SPECTRA	:
MASS SPECTRA	:	FAB-MS (negative ion mode); m/z 1531.91 (M-Na)-, 1553.89 (M-H)- (Ref. 3016)
OTHER SPECTRA	:

Chemical Synthesis

Methyl (4-O-acetyl-2-O-benzoyl-3-O-levulinoyl-a-D-glucopyranosyl trichloroacetimidate)uronate) was prepared from methyl [2-(trimethylsilyl)ethyl b-D-glucopyranosid]uronate via selective 4-O-acetylation, 2-O-benzoylation, 3-O-levulinoylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation. The coupling of the donor with 2-(trimethylsilyl)ethyl 2,4,6-tri-O-benzyl-b-D-galactopyranoside using trimethylsilyl trifluoromethanesulfonate gave 2-(trimethylsilyl)ethyl O-(methyl 4-O-acetyl-2-O-ben-zoyl-3-O-levulinoyl-b-D-glucopyranosyluronate)-(1-3)-2,4,6-tri-O-benzyl-b-D-galact-opyranoside, which was transformed via removal of the benzyl group, benzoylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation into the disaccharide donor. On the other hand, 2-(trimethylsilyl)ethyl O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-b-D-glucopyranosyl)-(1-3)-O-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-(1-4)-2,3,6-tri-O-benzyl-b-D-glucopyranoside as the acceptor was prepared from
2-(trimethylsilyl)ethyl 3,6-di-O-benzyl-2-deoxy-2-phthalimido-b-D-glucopyranoside via O-acetylation, removal of the 2-(trimethylsilyl)ethyl group, imidate formation, coupling with 2-(trimethylsilyl)ethyl O-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-(1-4)-2,3,6-tri-O-benzyl-b-D-glucopyrano-side, removal of the O-acetyl and N-phthaloyl group followed by N-acetyla-tion. Condensation of thedisaccharide donor with the trisaccharide acceptor using trimethylsilyl trifluoromethanesulfonate afforded the desired pentasaccharide, which was transformed by removal of the benzyl group, O-acetylation, removal of the 2-(trimethylsilyl)ethyl group and imidate formation into the pentasaccharide donor. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol withthe imidate gave the desired b-glycoside, which was transformed into the target compound, via reduction of the azido group, coupling with octadecanoic acid, selective removal of the levulinoyl group, O-sulfation, hydrolysis of the methyl ester group and O-deacylation. (Ref. 3016)

Fatty acid C18:0

LCB d18:1

[3016]

AUTHOR	:	Isogai, Y., Kawase, T., Ishida, H., Kiso, M., and Hasegawa, A.
TITLE	:	Total synthesis of sulfated glucuronyl paraglobosides.
JOURNAL	:	Journal of Carbohydrate Chemistry
VOL	:	158 PAGE : 1001 -1023 (1996)

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