4)- (2,3,6-tri-O-benzoyl-beta-D-galactopyranosyl)-(1-->4)2,3,6-tri-O- benzoyl-beta-D-glucopyranoside and its 3"-O-acetylated analogue, 2-azidoethyl (3-O-acetyl-2,4,6-tri-O-benzyl- alpha-D-galactopyranosyl)-(1-->4)-(2,3,6-tri-O-benzoyl-beta-D- galactopyranosyl)-(1-->4)-2,3,6-tri-O-benzoyl-beta-D-glucopyranoside, in yields of 85 and 83%, respectively. Deacetylation of the latter compound and subsequent glycosylation with 4-trichloroacetamidophenyl 3,4,6-tri-O-acetyl-2-deoxy-1-thio-2-trichloroacetamido-beta-D- galactopyranoside and 4-trichloroacetamidophenyl 4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O- acetyl-beta-D-galactopyranosyl)-1-thio-2-trichloroacetamido-beta-D- galactopyranoside in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid resulted in the corresponding selectively protected derivatives of tetrasaccharide GalNAc(beta 1-->3)Gal(alpha 1-->4)Gal(beta 1-->4)Glc beta-OCH2CH2N3 and pentasaccharide Gal(beta 1-->3)GalNAc(beta 1-->3)Gal(alpha 1-->4)Gal(beta 1-->4)Glc beta-OCH2CH2N3 in 88 and 73% yields, respectively. Removal of O-protecting groups, substitution of acetyl group for N-trichloroacetyl group, and reduction of the aglycone azide group resulted in the target 2-aminoethyl globo-tri-, -tetra-, and -pentasaccharide, respectively. -->
ISSN: 1068-1620
Přístupová URL adresa: https://explore.openaire.eu/search/publication?articleId=doi_________::f1bcc90b46450bc3e4845410dc6437e1
https://doi.org/10.1023/a:1024905419008
Přírůstkové číslo: edsair.doi...........f1bcc90b46450bc3e4845410dc6437e1
Autor: Alexey G. Gerbst, Alexander S. Shashkov, Iu E Tsvetkov, Nikolay E. Nifant'ev, Elena A. Khatuntseva, P. E. Cheshev
Rok vydání: 2003
Předmět:
Zdroj: Russian Journal of Bioorganic Chemistry. 29:372-381
ISSN: 1068-1620
Popis: 4-O-Glycosylation of 2-azidoethyl 2,3,6-tri-O-benzoyl-4-O-(2,3,6-tri-O-benzoyl-beta-D-galactopyranosyl)-beta- D-glucopyranoside with ethyl 2,3,4,6-tetra-O-benzyl- and ethyl 3-O-acetyl-2,4,6-tri-O-benzyl-1-thio-alpha-D-galactopyranoside in the presence of methyl trifluoromethanesulfonate led to trisaccharide 2-azidoethyl (2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl)-(1-->4)- (2,3,6-tri-O-benzoyl-beta-D-galactopyranosyl)-(1-->4)2,3,6-tri-O- benzoyl-beta-D-glucopyranoside and its 3"-O-acetylated analogue, 2-azidoethyl (3-O-acetyl-2,4,6-tri-O-benzyl- alpha-D-galactopyranosyl)-(1-->4)-(2,3,6-tri-O-benzoyl-beta-D- galactopyranosyl)-(1-->4)-2,3,6-tri-O-benzoyl-beta-D-glucopyranoside, in yields of 85 and 83%, respectively. Deacetylation of the latter compound and subsequent glycosylation with 4-trichloroacetamidophenyl 3,4,6-tri-O-acetyl-2-deoxy-1-thio-2-trichloroacetamido-beta-D- galactopyranoside and 4-trichloroacetamidophenyl 4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O- acetyl-beta-D-galactopyranosyl)-1-thio-2-trichloroacetamido-beta-D- galactopyranoside in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid resulted in the corresponding selectively protected derivatives of tetrasaccharide GalNAc(beta 1-->3)Gal(alpha 1-->4)Gal(beta 1-->4)Glc beta-OCH2CH2N3 and pentasaccharide Gal(beta 1-->3)GalNAc(beta 1-->3)Gal(alpha 1-->4)Gal(beta 1-->4)Glc beta-OCH2CH2N3 in 88 and 73% yields, respectively. Removal of O-protecting groups, substitution of acetyl group for N-trichloroacetyl group, and reduction of the aglycone azide group resulted in the target 2-aminoethyl globo-tri-, -tetra-, and -pentasaccharide, respectively.
Databáze: OpenAIRE
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