title: Synthesis of disaccharide glycosyl donors suitable for introduction of the beta-D-Gal p-(1-->3)-alpha-and-beta-D-Gal pNAc groups.
abstract: 2-(Trimethylsilyl)ethyl 2-azido-4,6-O-benzylidene-2-deoxy-beta-D- galactopyranoside (4) was glycosylated with phenyl 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-galactopyranoside to give 2-(trimethylsilyl)ethyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D-galactopyranoside (6) in 99% yield. Removal of the benzylidene group and acetylation gave the key intermediate 2-(trimethylsilyl)ethyl 4,6-di-O-acetyl-2-azido-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D-galactopyranoside (7), which was transformed into methyl 4,6-di-O-acetyl-2-deoxy-2-phthalimido-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-1-thio-beta-D-galactopyranosid e (9) in two steps in an overall yield of 69%. Similarly, 7 was transformed in two steps into 4,6-di-O-acetyl-2-azido-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-alpha-D-galactopyranosyl bromide (11) in an over-all yield of 86%. Compounds 9 and 11 are suitable glycosyl donors for introduction of the beta-D-Gal p-(1-->3)-beta- and -alpha-D-Gal pNAc groups.
authors.affiliation: Chemical Center, Lund Institute of Technology, University of Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Wilstermann
authors.forename: G
authors.initials: G
authors.lastname: Magnusson
mesh_terms: D000116:Acetylgalactosamine / Q000737:chemistry; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D005690:Galactose / Q000737:chemistry; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015394:Molecular Structure
chemical_list: D004187:Disaccharides; D000116:Acetylgalactosamine; D005690:Galactose