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Convergent Synthesis of 4-O-Phosphorylated l-glycero-d-manno-Heptosyl Lipopolysaccharide Core Oligosaccharides Based on Regioselective Cleavage of a 6,7-O-Tetraisopropyldisiloxane-1,3-diyl Protecting Group
[Image: see text] The structurally conserved lipopolysaccharide core region of many Gram-negative bacteria is composed of trisaccharides containing 4-O-phosphorylated l-glycero-d-manno-heptose (l,d-Hep) units, which act as ligands for antibodies and lectins. The disaccharides Glc-(1→3)-Hep4P Hep-(1→...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical
Society
2013
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898546/ https://www.ncbi.nlm.nih.gov/pubmed/24359545 http://dx.doi.org/10.1021/jo402312x |
Sumario: | [Image: see text] The structurally conserved lipopolysaccharide core region of many Gram-negative bacteria is composed of trisaccharides containing 4-O-phosphorylated l-glycero-d-manno-heptose (l,d-Hep) units, which act as ligands for antibodies and lectins. The disaccharides Glc-(1→3)-Hep4P Hep-(1→3)-Hep4P and Hep-(1→7)-Hep4P and the branched trisaccharide Glc-(1→3)-[Hep-(1→7)]-Hep4P, respectively, have been synthesized from a methyl heptopyranoside acceptor in less than 10 steps. The synthetic strategy was based on the early introduction of a phosphotriester at position 4 of heptose followed by a regioselective opening of a 6,7-O-(1,1,3,3-tetraisopropyl-1,3-disiloxane-1,3-diyl) group allowing for a straightforward access to glycosylation at position 7. Perbenzylated N-phenyl trifluoroacetimidate glucosyl and heptosyl derivatives served as α-selective glycosyl donors. |
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