title: Galabiosyl donors; efficient synthesis from 1,2,3,4, 6-penta-O-acetyl-beta-D-galactopyranose.
abstract: 1,2,3,4,6-Penta-O-acetyl-beta-D-galactopyranose was transformed into phenyl 2,3,4,6-tetra-O-benzyl-1-thio-beta-D-galactopyranoside (5) and 4-methoxyphenyl 2,3,6-tri-O-benzoyl-beta-D-galactopyranoside (8) in 73% (two steps) and 58% (three steps) yield, respectively. Glycosylation of the acceptor 8 with donor 5 using N-iodosuccinimide-trimethylsilyl trifluoromethanesulfonate as promoter furnished the galabioside 9 (8.8 g) in 95% yield. Further transformations provided in high yields anomerically-activated galabiosides (thioglycoside (1), trichloroacetimidate (2), and bromosugar (3)) suitable for use as glycosyl donors in syntheses of galabiose-containing oligosaccharides. Several of the compounds reported here are crystalline, which greatly simplified purifications.
authors.affiliation: Organic Chemistry 2, Center for Chemistry and Chemical Engineering, Lund University, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Ohlsson
authors.forename: G
authors.initials: G
authors.lastname: Magnusson
mesh_terms: D003460:Crystallization; D004187:Disaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D005697:Galactosides / Q000737:chemistry; D006031:Glycosylation; D015394:Molecular Structure; D010368:Pectins / Q000737:chemistry; D011956:Receptors, Cell Surface / Q000737:chemistry; D013400:Sugar Acids / Q000737:chemistry
chemical_list: D004187:Disaccharides; D005697:Galactosides; D011956:Receptors, Cell Surface; D013400:Sugar Acids; C033639:glycolipid receptor; C032103:4-O-alpha-D-galactopyranosyl-D-galactose; C020450:1,2,3,4,6-penta-O-acetylgalactopyranose; D010368:Pectins; C090179:digalacturonic acid