Synthesis of Neu5Ac- and Neu5Gc-alpha-(2-->6')-lactosamine 3-aminopropyl glycosides.
In order to prepare 3-aminopropyl glycosides of Neu5Ac-alpha-(2-->6')-lactosamine trisaccharide 1, and its N-glycolyl containing analogue Neu5Gc-alpha-(2-->6')-lactosamine 2, a series of lactosamine acceptors with two, three, and four free OH groups in the galactose residue was studied in glycosylations with a conventional sialyl donor phenyl [methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero-alpha- and beta-D-galacto-2-nonulopyranosid]onates (3) and a new donor phenyl [methyl 4,7,8,9-tetra-O-acetyl-5-(N-tert-butoxycarbonylacetamido)-3,5-dideoxy-2-thio-D-glycero-alpha- and beta-D-galacto-2-nonulopyranosid]onates (4), respectively. The lactosamine 4',6'-diol acceptor was found to be the most efficient in glycosylation with both 3 and 4, while imide-type donor 4 gave slightly higher yields with all acceptors, and isolation of the reaction products was more convenient. In the trisaccharides, obtained by glycosylation with donor 4, the 5-(N-tert-butoxycarbonylacetamido) moiety in the neuraminic acid could be efficiently transformed into the desired N-glycolyl fragment, indicating that such protected oligosaccharide derivatives are valuable precursors of sialo-oligosaccharides containing N-modified analogues of Neu5Ac.
Sherman
A A
AA
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow.
Yudina
O N
ON
Shashkov
A S
AS
Menshov
V M
VM
Nifant'ev
N E
NE
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006031:Glycosylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis*; D014312:Trisaccharides / Q000138:chemical synthesis*
C430203:5-N-acetylsialyl-2-6'-lactosamine 3-aminopropyl glycoside; C430204:5-N-glycolylsialyl-2-6'-lactoamine 3-aminopropyl glycoside; D009844:Oligosaccharides; D014312:Trisaccharides; C016735:sialooligosaccharides