PubMed:1811854 JSONTXT

{"project":"GlyCosmos6-Glycan-Motif-Image","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"Glycan_Motif"},{"id":"T2","span":{"begin":118,"end":122},"obj":"Glycan_Motif"}],"attributes":[{"id":"A1","pred":"image","subj":"T1","obj":"https://api.glycosmos.org/wurcs2image/0.10.0/png/binary/G03277YI"},{"id":"A2","pred":"image","subj":"T2","obj":"https://api.glycosmos.org/wurcs2image/0.10.0/png/binary/G03277YI"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"GlyCosmos6-Glycan-Motif-Structure","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"https://glytoucan.org/Structures/Glycans/G03277YI"},{"id":"T2","span":{"begin":118,"end":122},"obj":"https://glytoucan.org/Structures/Glycans/G03277YI"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"Glycosmos6-GlycoEpitope","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"http://www.glycoepitope.jp/epitopes/EP0048"},{"id":"T2","span":{"begin":118,"end":122},"obj":"http://www.glycoepitope.jp/epitopes/EP0048"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"sentences","denotations":[{"id":"TextSentencer_T1","span":{"begin":0,"end":86},"obj":"Sentence"},{"id":"TextSentencer_T2","span":{"begin":87,"end":193},"obj":"Sentence"},{"id":"TextSentencer_T3","span":{"begin":194,"end":643},"obj":"Sentence"},{"id":"TextSentencer_T4","span":{"begin":644,"end":1058},"obj":"Sentence"},{"id":"TextSentencer_T5","span":{"begin":1059,"end":1217},"obj":"Sentence"},{"id":"TextSentencer_T6","span":{"begin":1218,"end":1404},"obj":"Sentence"},{"id":"TextSentencer_T7","span":{"begin":1405,"end":1772},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":86},"obj":"Sentence"},{"id":"T2","span":{"begin":87,"end":193},"obj":"Sentence"},{"id":"T3","span":{"begin":194,"end":643},"obj":"Sentence"},{"id":"T4","span":{"begin":644,"end":1058},"obj":"Sentence"},{"id":"T5","span":{"begin":1059,"end":1217},"obj":"Sentence"},{"id":"T6","span":{"begin":1218,"end":1404},"obj":"Sentence"},{"id":"T7","span":{"begin":1405,"end":1772},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"GlyCosmos15-Glycan","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"Glycan"},{"id":"T2","span":{"begin":118,"end":122},"obj":"Glycan"}],"attributes":[{"id":"A1","pred":"glycosmos_id","subj":"T1","obj":"https://glycosmos.org/glycans/show/G03277YI"},{"id":"A3","pred":"image","subj":"T1","obj":"https://api.glycosmos.org/wurcs2image/latest/png/binary/G03277YI"},{"id":"A2","pred":"glycosmos_id","subj":"T2","obj":"https://glycosmos.org/glycans/show/G03277YI"},{"id":"A4","pred":"image","subj":"T2","obj":"https://api.glycosmos.org/wurcs2image/latest/png/binary/G03277YI"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"Glycan-GlyCosmos","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"Glycan"},{"id":"T2","span":{"begin":118,"end":122},"obj":"Glycan"}],"attributes":[{"id":"A1","pred":"glycosmos_id","subj":"T1","obj":"https://glycosmos.org/glycans/show/G03277YI"},{"id":"A3","pred":"image","subj":"T1","obj":"https://api.glycosmos.org/wurcs2image/latest/png/binary/G03277YI"},{"id":"A2","pred":"glycosmos_id","subj":"T2","obj":"https://glycosmos.org/glycans/show/G03277YI"},{"id":"A4","pred":"image","subj":"T2","obj":"https://api.glycosmos.org/wurcs2image/latest/png/binary/G03277YI"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"GlyCosmos15-Taxon","denotations":[{"id":"T1","span":{"begin":231,"end":238},"obj":"Organism"},{"id":"T2","span":{"begin":417,"end":424},"obj":"Organism"}],"attributes":[{"id":"A1","pred":"db_id","subj":"T1","obj":"100829"},{"id":"A2","pred":"db_id","subj":"T2","obj":"100829"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"GlyCosmos15-GlycoEpitope","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"http://purl.jp/bio/12/glyco/glycan#Glycan_epitope"},{"id":"T2","span":{"begin":118,"end":122},"obj":"http://purl.jp/bio/12/glyco/glycan#Glycan_epitope"}],"attributes":[{"id":"A1","pred":"glycoepitope_id","subj":"T1","obj":"http://www.glycoepitope.jp/epitopes/EP0048"},{"id":"A2","pred":"glycoepitope_id","subj":"T2","obj":"http://www.glycoepitope.jp/epitopes/EP0048"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"GlyCosmos15-Sentences","blocks":[{"id":"T1","span":{"begin":0,"end":86},"obj":"Sentence"},{"id":"T2","span":{"begin":87,"end":193},"obj":"Sentence"},{"id":"T3","span":{"begin":194,"end":643},"obj":"Sentence"},{"id":"T4","span":{"begin":644,"end":1058},"obj":"Sentence"},{"id":"T5","span":{"begin":1059,"end":1217},"obj":"Sentence"},{"id":"T6","span":{"begin":1218,"end":1404},"obj":"Sentence"},{"id":"T7","span":{"begin":1405,"end":1772},"obj":"Sentence"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"NCBITAXON","denotations":[{"id":"T1","span":{"begin":231,"end":238},"obj":"OrganismTaxon"},{"id":"T2","span":{"begin":417,"end":424},"obj":"OrganismTaxon"}],"attributes":[{"id":"A1","pred":"db_id","subj":"T1","obj":"100829"},{"id":"A2","pred":"db_id","subj":"T2","obj":"100829"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}

{"project":"GlyCosmos-GlycoEpitope","denotations":[{"id":"T1","span":{"begin":53,"end":57},"obj":"http://purl.jp/bio/12/glyco/glycan#Glycan_epitope"},{"id":"T2","span":{"begin":118,"end":122},"obj":"http://purl.jp/bio/12/glyco/glycan#Glycan_epitope"}],"attributes":[{"id":"A1","pred":"glycoepitope_id","subj":"T1","obj":"http://www.glycoepitope.jp/epitopes/EP0048"},{"id":"A2","pred":"glycoepitope_id","subj":"T2","obj":"http://www.glycoepitope.jp/epitopes/EP0048"}],"text":"Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.\nTotal syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds."}