- Synthesis of neoglycoconjugates containing 4-amino-4-deoxy- l -arabinose epitopes corresponding to the inner core of burkholderia and proteus lipopolysaccharides
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Disaccharides that contain 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) and D-glycero-D-talo-oct-2-ulosonic acid (Ko) substituted at the 8-position by 4-amino-4-deoxy-β-L-arabinopyranosyl (Ara4N) residues have been prepared. Coupling an N-phenyltrifluoroacetimidate-4-azido-4-deoxy-L-arabinosylglycosyl donor to acetyl-protected allyl glycosides of Kdo and Ko afforded anomeric mixtures of disaccharide products in 74 and 90 % yield, respectively, which were separated by chromatography. Further extension of an intermediate Ara4N-(1→8)-Kdo disaccharide acceptor, which capitalized on a regioselective glycosylation with a Kdo bromide donor under Helferich conditions, afforded the branched trisaccharide α-Kdo-(2→4)[β-L- Ara4N-(1→8)]-α-Kdo derivative. Deprotection of the protected di- and trisaccharide allyl glycosides was accomplished by TiCl4-promoted benzyl ether cleavage followed by the removal of ester groups and reduction of the azido group with thiol or Staudinger reagents, respectively. The reaction of the anomeric allyl group with 1,3-propanedithiol under radical conditions afforded the thioether-bridged spacer glycosides, which were efficiently coupled to maleimide-activated bovine serum albumin. The neoglycoconjugates serve as immunoreagents with specificity for inner core epitopes of Burkholderia and Proteus lipopolysaccharides.
- Blaukopf, Markus,Mueller, Bernhard,Hofinger, Andreas,Kosma, Paul
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p. 119 - 131
(2012/02/02)
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- Evaluation of thioglycosides of Kdo as glycosyl donors
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The use of Kdo thioglycosides as glycosyl donors using DMTST, IBr/AgOTf and NIS/AgOTf as promoters has been evaluated. Activation at low temperature allowed to escape the formation of 2,3-glycal byproducts to give glycosides in high yield and with good β-
- Mannerstedt, Karin,Ekeloef, Kerstin,Oscarson, Stefan
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p. 631 - 637
(2008/03/13)
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- Synthesis of C-8 deuterated glycosides of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) related to chlamydial lipopolysaccharides
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Methyl glycosides of Kdo and a (2→8)-linked Kdo disaccharide were prepared which contain a deuterium label at C-8 of the reducing unit. The label was introduced in fair diastereoselectivity upon reduction of an aldehyde group using a chiral borane complex derived from N-benzyloxycarbonyl-(S)-proline which produced the 8-(S)-deuterated derivative as the major isomer. Further coupling with a Kdo bromide gave the α-(2→8)-linked disaccharide in good yield. The deprotected disaccharide serves as a model for NMR spectroscopic studies on the side chain conformation of a carbohydrate epitope from the bacterial pathogen Chlamydia.
- Kosma, Paul,Strobl, Martina,Hofinger, Andreas,Duus, Jens .,Petersen, Bent O.,Bock, Klaus,Brade, Helmut
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p. 561 - 570
(2007/10/03)
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- Building Units of Oligosaccharides, XCIV. - Synthesis of KDO-Containing Tri- and Tetrasaccharide Sequences of the Inner Core and Lipoid A Region of Lipopolysaccharides
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The glycosyl acceptor 18, who contains two glycosidically β(1->6) linked 2-amino-2-deoxy-D-glucose residues was synthesized.The two amino groups are acetylated with (R)-3-hydroxytetradecanoic acid.The 6' position of 18 is suitable for selective glycosidat
- Paulsen, Hans,Krogmann, Christof
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p. 1203 - 1214
(2007/10/02)
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- Building Units of Oligosaccharides, XCII. - Synthesis of Trisaccharid Units of the Inner Core Region of Lipopolysaccharides
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L-glycero-D-manno-Heptose derivative 9 reacts with KDO-glycosyl acceptor 6 stereoselectively to give the α(1->5)-linked disaccharide 10.Coupling of now available KDO-glycosyl acceptor 12 with KDO bromide 2 leads to the branched α(2'->4)-α(1''->5)-linked t
- Paulsen, Hans,Heitmann, Axel C.
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p. 655 - 664
(2007/10/02)
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- SYNTHESIS OF ALTERNATE LINEAR AND BRANCHED REPEATING UNITS OF THE Escherichia coli LP 1092 CAPSULAR POLYSACCHARIDE CONTAINING 3-DEOXY-α-D-manno-OCTULOSONIC ACID (KDO) LINKED TO SECONDARY POSITIONS OF D-RIBOSE
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The oligosaccharides, methyl 3-O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-β-D-ribofuranoside, methyl 2-O-β-D-ribofuranosyl-3-O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-β-D-ribofuranoside, and methyl O-(sodium 3-deoxy-α-D-manno-2-octulopy
- Kosma, Paul,Christian, Rudolf,Schulz, Gerhard,Unger, Frank M.
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p. 239 - 254
(2007/10/02)
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- Building Units of Oligosaccharides, LII. - Synthesis of Disaccharides Containing 3-Deoxy-D-manno-2-octulosonic Acid (KDO) and D-Glucosamine
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The pyranosyl bromide 2 of 3-deoxy-D-manno-2-octulosonic acid (KDO) can be coupled favourably with benzyl 2-benzyloxycarbonylamino-2-deoxy-4,6-O-ethyliden-α-D-glucopyranoside (7) which yields the (2-->3)-glycosidically linked disaccharide containing KDO a
- Paulsen, Hans,Hayauchi, Yutaka,Unger, Frank M.
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p. 1270 - 1287
(2007/10/02)
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