The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Gérard Strecker - One of the best experts on this subject based on the ideXlab platform.
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structural analysis of o linked oligosaccharide Alditols by electrospray tandem mass spectrometry after mild periodate oxidation and derivatization with 2 aminopyridine
Analytical Biochemistry, 1998Co-Authors: Willy Morelle, Jerome Lemoine, Gérard StreckerAbstract:O-linked oligosaccharide-Alditols were analyzed by a combination of high-performance liquid chromatography (HPLC) and electrospray-tandem mass spectrometry (ESI-MS/MS). First, oligosaccharide-Alditols were treated with sodium meta-periodate under conditions where core N-acetylgalactosaminitol is specifically degraded. The resulting fragments were labeled with 2-aminopyridine and purified on a reversed-phase column. Pyridylamino oligosaccharides yielded protonated molecular ions in positive-ion ES-MS and gave Y-series sequence ions, arising from glycosidic cleavages, by ESI-tandem mass spectrometry. Information on sugar sequence and branching of oligosaccharides linked at C6 and C3 to the N-acetylgalactosaminitol can be obtained. A systematic study of various oligosaccharide-Alditols demonstrated that this approach constitutes a powerful tool for the structural characterization of O-glycans available only in limited quantities.
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Structural analysis of hexa to dodecaoligosaccharide-Alditols released by reductive β-elimination from oviducal mucins of Bufo bufo
Glycobiology, 1997Co-Authors: Willy Morelle, Gérard StreckerAbstract:Hexa to dodecasacchar ide-Alditols of the jelly coat surrounding the eggs of the toad Bufo bufo were studied by methylation analysis, MALDI-TOF mass spectrometry, and H-NMR spectroscopy. These highly species-specific carbohydrate chains exhibit new structural features, such as the elongation of the blood group A determinant with an external a-l,3-linked galactose unit, or ramification belonging from a fucosylated galactose. The most representative oligosaccharide-alditol of the series was defined as following:
Gilles Demailly - One of the best experts on this subject based on the ideXlab platform.
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New Synthesis of Alditol Thiaheterocycles via Ring Closure of Vicinal Bis‐Cyclic Thionocarbonates of Alditols.
ChemInform, 2010Co-Authors: Sami Halila, Mohammed Benazza, Gilles DemaillyAbstract:A new thiaheterocyclisation of Alditols involving bis-cyclic thionocarbonate derivatives as bielectrophilic intermediates is reported. The polyhydroxylated tetrahydrothiophene, tetrahydropyrane and thiepane rings from erythritol, d,l-threitol, d-arabinitol, d-mannitol and galactitol were efficiently obtained.
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Regioselective synthesis of alditol vicinal bis-cyclic thionocarbonates via alditol stannylene acetal complexes as a short and efficient route to α, ω-diiodoalditol derivatives
Carbohydrate research, 2002Co-Authors: Sami Halila, Mohammed Benazza, Gilles DemaillyAbstract:The bis-cyclic thionocarbonates of Alditols (pentitols and hexitols) were quickly and easily obtained from alditol stannylene complexes and phenyl chlorothionoformate (PhOC(S)Cl) in good yields. Acetylation of isolated free alditol bis-thionocarbonates and subsequent iodination using methyl iodide under pressure led to alpha,omega-diiodo derivatives of Alditols in good to excellent isolated yields (67-93%).
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New synthesis of alditol thiaheterocycles via ring closure of vicinal bis-cyclic thionocarbonates of Alditols
Tetrahedron Letters, 2002Co-Authors: Sami Halila, Mohammed Benazza, Gilles DemaillyAbstract:A new thiaheterocyclisation of Alditols involving bis-cyclic thionocarbonate derivatives as bielectrophilic intermediates is reported. The polyhydroxylated tetrahydrothiophene, tetrahydropyrane and thiepane rings from erythritol, d,l-threitol, d-arabinitol, d-mannitol and galactitol were efficiently obtained.
Willy Morelle - One of the best experts on this subject based on the ideXlab platform.
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structural analysis of o linked oligosaccharide Alditols by electrospray tandem mass spectrometry after mild periodate oxidation and derivatization with 2 aminopyridine
Analytical Biochemistry, 1998Co-Authors: Willy Morelle, Jerome Lemoine, Gérard StreckerAbstract:O-linked oligosaccharide-Alditols were analyzed by a combination of high-performance liquid chromatography (HPLC) and electrospray-tandem mass spectrometry (ESI-MS/MS). First, oligosaccharide-Alditols were treated with sodium meta-periodate under conditions where core N-acetylgalactosaminitol is specifically degraded. The resulting fragments were labeled with 2-aminopyridine and purified on a reversed-phase column. Pyridylamino oligosaccharides yielded protonated molecular ions in positive-ion ES-MS and gave Y-series sequence ions, arising from glycosidic cleavages, by ESI-tandem mass spectrometry. Information on sugar sequence and branching of oligosaccharides linked at C6 and C3 to the N-acetylgalactosaminitol can be obtained. A systematic study of various oligosaccharide-Alditols demonstrated that this approach constitutes a powerful tool for the structural characterization of O-glycans available only in limited quantities.
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Structural analysis of hexa to dodecaoligosaccharide-Alditols released by reductive β-elimination from oviducal mucins of Bufo bufo
Glycobiology, 1997Co-Authors: Willy Morelle, Gérard StreckerAbstract:Hexa to dodecasacchar ide-Alditols of the jelly coat surrounding the eggs of the toad Bufo bufo were studied by methylation analysis, MALDI-TOF mass spectrometry, and H-NMR spectroscopy. These highly species-specific carbohydrate chains exhibit new structural features, such as the elongation of the blood group A determinant with an external a-l,3-linked galactose unit, or ramification belonging from a fucosylated galactose. The most representative oligosaccharide-alditol of the series was defined as following:
Sergio Castillón - One of the best experts on this subject based on the ideXlab platform.
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Stereoselective Synthesis of Both Enantiomers of 1,4‐Anhydro‐Alditols, 1,4‐Anhydro‐2‐amino‐Alditols and D‐ and L‐Isonucleosides from 2,3‐O‐Isopropylidene‐D‐glyceraldehyde Using Iodine‐Induced Cyclization as the Key Step.
ChemInform, 2010Co-Authors: Fernando Bravo, Yolanda Díaz, Sergio CastillónAbstract:Abstract We have stereoselectively prepared the enantiomeric 1,4-anhydro-Alditols (−)-15 and (+)-15, 1,4-anhydro-2-amino-Alditols (−)-19 and (+)-19, and isonucleosides (−)-22, (+)-22 and 25, from 2,3-O-isopropylidene- d -glyceraldehyde. The key step was the iodine-induced cyclization of 4-pentene-1,2,3-triols 2 and 3 to give, respectively, the tetrahydrofuran derivatives 4 and 5. In these compounds we have optimized the substitution of iodine for oxygen-bearing groups. Results were best when we used potassium superoxide as a nucleophile.
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Stereoselective synthesis of both enantiomers of 1,4-anhydro-Alditols, 1,4-anhydro-2-amino-Alditols and d- and l-isonucleosides from 2,3-O-isopropylidene-d-glyceraldehyde using iodine-induced cyclization as the key step
Tetrahedron: Asymmetry, 2001Co-Authors: Fernando Bravo, Yolanda Díaz, Sergio CastillónAbstract:Abstract We have stereoselectively prepared the enantiomeric 1,4-anhydro-Alditols (−)-15 and (+)-15, 1,4-anhydro-2-amino-Alditols (−)-19 and (+)-19, and isonucleosides (−)-22, (+)-22 and 25, from 2,3-O-isopropylidene- d -glyceraldehyde. The key step was the iodine-induced cyclization of 4-pentene-1,2,3-triols 2 and 3 to give, respectively, the tetrahydrofuran derivatives 4 and 5. In these compounds we have optimized the substitution of iodine for oxygen-bearing groups. Results were best when we used potassium superoxide as a nucleophile.
Sami Halila - One of the best experts on this subject based on the ideXlab platform.
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New Synthesis of Alditol Thiaheterocycles via Ring Closure of Vicinal Bis‐Cyclic Thionocarbonates of Alditols.
ChemInform, 2010Co-Authors: Sami Halila, Mohammed Benazza, Gilles DemaillyAbstract:A new thiaheterocyclisation of Alditols involving bis-cyclic thionocarbonate derivatives as bielectrophilic intermediates is reported. The polyhydroxylated tetrahydrothiophene, tetrahydropyrane and thiepane rings from erythritol, d,l-threitol, d-arabinitol, d-mannitol and galactitol were efficiently obtained.
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Regioselective synthesis of alditol vicinal bis-cyclic thionocarbonates via alditol stannylene acetal complexes as a short and efficient route to α, ω-diiodoalditol derivatives
Carbohydrate research, 2002Co-Authors: Sami Halila, Mohammed Benazza, Gilles DemaillyAbstract:The bis-cyclic thionocarbonates of Alditols (pentitols and hexitols) were quickly and easily obtained from alditol stannylene complexes and phenyl chlorothionoformate (PhOC(S)Cl) in good yields. Acetylation of isolated free alditol bis-thionocarbonates and subsequent iodination using methyl iodide under pressure led to alpha,omega-diiodo derivatives of Alditols in good to excellent isolated yields (67-93%).
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New synthesis of alditol thiaheterocycles via ring closure of vicinal bis-cyclic thionocarbonates of Alditols
Tetrahedron Letters, 2002Co-Authors: Sami Halila, Mohammed Benazza, Gilles DemaillyAbstract:A new thiaheterocyclisation of Alditols involving bis-cyclic thionocarbonate derivatives as bielectrophilic intermediates is reported. The polyhydroxylated tetrahydrothiophene, tetrahydropyrane and thiepane rings from erythritol, d,l-threitol, d-arabinitol, d-mannitol and galactitol were efficiently obtained.