161602-50-2Relevant academic research and scientific papers
Preparation of Diastereomeric 3,4-O-Pyruvate Acetal-Containing D-Galactopyranose Derivatives, Structural Assignment and Use for Oligosaccharide Synthesis
Ziegler, Thomas,Herold, Gerhard
, p. 859 - 866 (2007/10/02)
Treatment of phenyl 1-thio- and allyl 2,6-di-O-benzoyl-D-galactopyranosides 3 with methyl pyruvate and BF3*Et2O in various solvents gave 1,6-anhydro-3,4-di-O-benzoyl-2-deoxy-2-phenylthio-β-D-idopyranose (4) and the corresponding diastereomers of 3,4-O-pyruvate acetal-containing galactosides 5.The phenyl 1-thio-β-galactoside R-5a and the allyl α-galactoside R-5b were both converted into methyl 3,4-O--β-D-galactopyranoside (9), the structure of which as well as that of 4 was confirmed by X-ray crystallography.Compound R-5a was converted into 5-pentyl 6-O-benzoyl-3,4-O--β-D-galactopyranoside (18) by using the (2-chloroacetoxymethyl)benzoyl (CAMB) group for the temporary protection of position 2.Glucosamination of 18 and subsequent deblocking of the intermediate disaccharide gave β-D-GlcpNAc-(1-->2)-3,4-(S)-pyruvate-β-D-Galp-O(CH2)5NH2 (21) which represents a fragment of the Escherichia coli K 47 polysaccharide. - Key Words: Galactosides, 3,4-pyruvylated / Oligosaccharides / Carbohydrates / Escherichia coli
