Synthesis of alpha-D-Glcp-(1-3)-alpha-D-Galf-(1-2)-alpha-L-Rhap constituent of the CPS of Streptococcus pneumoniae 22F. Effect of 3-O-substitution in 1,2-cis alpha-D-galactofuranosylation
The synthesis of the trisaccharide a-D-Glcp-(1-3)-a-D-Galf-(1-2)-L-Rhap (3) constituent of Streptococcus pneumonia 22F was achieved with complete diastereoselectively. This is the first example of a synthesis of an internal a-D-Galf containing oligosaccharide of a pathogen microorganism. Allyl α-D-g...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/8157 |
| Acceso en línea: | http://hdl.handle.net/11336/8157 |
| Access Level: | acceso abierto |
| Palabra clave: | Glycosylation 1,2-Cis Substitution Effect Galactofuranose Oligosaccharide https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | The synthesis of the trisaccharide a-D-Glcp-(1-3)-a-D-Galf-(1-2)-L-Rhap (3) constituent of Streptococcus pneumonia 22F was achieved with complete diastereoselectively. This is the first example of a synthesis of an internal a-D-Galf containing oligosaccharide of a pathogen microorganism. Allyl α-D-galactofuranoside, used as novel precursor of the internal Galf, allowed the introduction of an orthogonal group at O-3. The trichloroacetimidate method was used for the construction of 1,2-cis a-D-galactofuranosyl linkage. The influence of the 3-O-substituent (PMB, Bz, PFBz, PMBz, TIPS) was evaluated in benzylated galactofuranosyl trichloroacetimidate donors in terms of yield and selectivity of a-D-Galf-(1-2)-a-L-Rhap product as well as donor rearrangement by-product. Complete stereoselectivity was observed with all protecting groups used in Galf donor, but the 3-O-benzoyl substitution gave the best yield. Protective groups were also evaluated in rhamnoside acceptor, benzyl substitution was a requirement for complete stereoselectivity. |
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