ISSN:
1573-4986
Keywords:
6-deoxy-Gal
;
4-deoxy-Gal
;
4,6-dideoxy-Gal
;
sialyl LeX
;
sialoglycoconjugate
;
selectin family
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Sialyl Lewis X ganglioside analogues containing 4-deoxy-, 6-deoxy-, and 4,6-dideoxy-d-galactopyranose in place ofd-galactopyranose have been synthesized. Glycosylations of 2-(trimethylsilyl)ethyl 2,6-di-O-benzyl-β-d-galactopyranoside and 2-(trimethylsilyl)ethyl β-d-fucopyranoside with the phenyl 2-thioglycoside derivative of sialic acid, usingN-iodosuccinimide (NIS)-trifluoromethanesulfonic acid (TfOH) as the promoter in acetonitrile, gave the desired 2-(trimethylsilyl)ethyl sialyl-α-(2→3)-β-d-galactopyranoside and-β-d-fucopyranoside, respectively. The sialylgalactose derivative obtained was then modified to 4-deoxy and 4,6-dideoxy derivatives. These were converted, byO-benzoylation, transformation of the 2-(trimethylsilyl)ethyl group to trichloroacetimidates, and introduction of the methylthio group with methylthiomethysilane, into the corresponding glycosyl donors, which were then coupled with 2-(trimethylsilyl)ethylO-(2,3,4-tri-O-benzyl-α-l-fucopyranosyl)-(1→3)-O-(2-acetamido-6-O-benzyl-2-deoxy-β-d-glucopyranosyl)-(1→3)-2,4,6- tri-O-benzyl-β-d-galactopyranoside in the presence of dimethyl(methylthio)sulfonium triflate (DMTST). The resulting pentasaccharides were each converted to the corresponding α-trichloroacetimidates, which, on coupling with (2S, 3R, 4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol, gave the desired sphingosine derivatives. Selective reduction of the azide group,N-acylation with octadecanoic acid,O-deacylation, and saponification of the methyl ester afforded the target compounds.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00731499
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