109714-38-7Relevant academic research and scientific papers
Use of the methyl (SEM) Protecting Group in Carbohydrate Chemistry. Fully Functionalized Rhamnose Acceptors and Donors for Use in Oligosaccharide Synthesis
Pinto, B. Mario,Buiting, Michiel M. W.,Reimer, Kerry B.
, p. 2177 - 2181 (2007/10/02)
The use of the methyl (SEM) acetal as a protecting group in carbohydrate chemistry is described.The compatibility of this group with a variety of protection/deprotection conditions normally encountered in oligosaccharide synthesi
Synthesis of Oligosaccharides Corresponding to Biological Repeating Units of Shigella flexneri Variant Y Polysaccharide. Part 1. Overall Strategy, Synthesis of a Key Trisaccharide Intermediate, and Synthesis of a Pentasaccharide
Pinto, B. Mario,Morisette, David G.
, p. 9 - 14 (2007/10/02)
The overall strategy for the synthesis of penta- up to octa-saccharides, representing the biological repeating unit of the Shigella flexneri serogroup Y lipopolysaccharide, is described.The key intermediate, the common terminal trisaccharide, α-L-Rhap-(1->2)-α-L-Rhap(1->3)-α-L-Rhap, has been synthesised by a series of Koenigs-Knorr reactions.A selectively protected rhamnose intermediate has been developed for the synthesis of this trisaccharide as its allyl glycoside.Allyl α-L-rhamnopyranoside was converted into the corresponding 2-O-benzoyl-4-O-benzyl derivative via a 2,3-orthobenzoate.Koenigs-Knorr reaction between this partially blocked rhamnoside and 2-O-acetyl-3,4-di-O-benzyl-α-L-rhamnopyranosyl chloride afforded the blocked disaccharide.Selective transesterification of the 2'-O-acetyl group in the presence of the 2-O-benzoate yielded the disaccharide, selectively deblocked at the C-2' position.Reaction with the same rhamnopyranosyl chloride gave the fully blocked trisaccharide.Deallylation, followed by treatment with NN-dimethyl(chloromethylene)ammonium chloride, then gave the corresponding trisaccharide chloride.In conjunction with the disaccharide methyl 2-O-(2'-acetamido-4',6'-O-benzylidene-2'-deoxy-β-D-glucopyranosyl)-3,4-di-O-benzyl-α-L-rhamnopyranoside, the synthesis of the blocked pentasaccharide was accomplished.Transesterification, followed by hydrogenolysis in aqueous acetic acid, afforded the pure pentasaccharide hapten, α-L-Rhap-(1->2)-α-L-Rhap-(1->3)-α-L-Rhap-(1->3)-β-D-GlcpNAc-(1->2)-α-L-Rhap, as its methyl glycoside, for use in binding studies and n.m.r. studies.
