Synthesis of the 2"-hydroxy, 4"-deoxy and 4"-epi analogues of beta-D-GalNAc-(1-->3)-alpha-D-Gal-(1-->4)-beta-D-Gal, the terminal trisaccharide of globotetraose.
{"title":"Synthesis of the 2\"-hydroxy, 4\"-deoxy and 4\"-epi analogues of beta-D-GalNAc-(1-->3)-alpha-D-Gal-(1-->4)-beta-D-Gal, the terminal trisaccharide of globotetraose.","authors":"U Nilsson, A Wendler, G Magnusson","doi":"10.3891/acta.chem.scand.48-0356","DOIUrl":null,"url":null,"abstract":"<p><p>Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phtha limido-beta-D - glucopyranoside 5 gave methyl 3,6-di-O-benzoyl-2,4-dideoxy-2-phthalimido-beta-D-glucopyranoside 6, which was converted into the corresponding methyl thioglycoside donor 9. Methylsulfenyl trifluoromethane-sulfonate-promoted glycosylation of 2-(trimethylsilyl)ethyl 2,3,6-tri-O-benzyl-4-O-(2,4,6-tri-O-benzyl-alpha-D-galactopyranosyl)-bet a-D- galactopyranoside 10, followed by removal of protecting groups gave the 4\"-deoxy analogue 12 of the terminal trisaccharide of globotetraose. Silver trifluoromethanesulfonate-promoted glycosylation of the same disaccharide alcohol 10 with 3,4,6-tri-O-acetyl-2-deoxy-2- phthalimido-alpha/beta-D-glucopyranosyl bromide 13 and 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide 16, followed by deblocking, gave the 2\"-hydroxy and 4\"-epi analogues 15 and 18, respectively.</p>","PeriodicalId":76966,"journal":{"name":"Acta chemica Scandinavica (Copenhagen, Denmark : 1989)","volume":"48 4","pages":"356-61"},"PeriodicalIF":0.0000,"publicationDate":"1994-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta chemica Scandinavica (Copenhagen, Denmark : 1989)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3891/acta.chem.scand.48-0356","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phtha limido-beta-D - glucopyranoside 5 gave methyl 3,6-di-O-benzoyl-2,4-dideoxy-2-phthalimido-beta-D-glucopyranoside 6, which was converted into the corresponding methyl thioglycoside donor 9. Methylsulfenyl trifluoromethane-sulfonate-promoted glycosylation of 2-(trimethylsilyl)ethyl 2,3,6-tri-O-benzyl-4-O-(2,4,6-tri-O-benzyl-alpha-D-galactopyranosyl)-bet a-D- galactopyranoside 10, followed by removal of protecting groups gave the 4"-deoxy analogue 12 of the terminal trisaccharide of globotetraose. Silver trifluoromethanesulfonate-promoted glycosylation of the same disaccharide alcohol 10 with 3,4,6-tri-O-acetyl-2-deoxy-2- phthalimido-alpha/beta-D-glucopyranosyl bromide 13 and 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide 16, followed by deblocking, gave the 2"-hydroxy and 4"-epi analogues 15 and 18, respectively.