The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
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.
Herbert H. Hill - One of the best experts on this subject based on the ideXlab platform.
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Determining the isomeric heterogeneity of neutral oligosaccharide-Alditols of bovine submaxillary mucin using negative ion traveling wave ion mobility mass spectrometry.
Analytical chemistry, 2015Co-Authors: Brad Bendiak, William F. Siems, David R. Gang, Herbert H. HillAbstract:Negative ions produced by electrospray ionization were used to evaluate the isomeric heterogeneity of neutral oligosaccharide-Alditols isolated from bovine submaxillary mucin (BSM). The oligosaccharide-Alditol mixture was preseparated on an off-line high-performance liquid chromatography (HPLC) column, and the structural homogeneity of individual LC fractions was investigated using a Synapt G2 traveling wave ion mobility spectrometer coupled between quadupole and time-of-flight mass spectrometers. Mixtures of isomers separated by both chromatography and ion mobility spectrometry were studied. Tandem mass spectrometry (MS/MS) of multiple mobility peaks having the same mass-to-charge ratio (m/z) demonstrated the presence of different structural isomers and not differences in ion conformations due to charge site location. Although the oligosaccharide-Alditol mixture was originally separated by HPLC, multiple ion mobility peaks due to structural isomers were observed for a number of oligosaccharide-Alditols f...
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Determining the Isomeric Heterogeneity of Neutral Oligosaccharide-Alditols of Bovine Submaxillary Mucin Using Negative Ion Traveling Wave Ion Mobility Mass Spectrometry
2015Co-Authors: Brad Bendiak, David R. Gang, William F. Siems, Herbert H. HillAbstract:Negative ions produced by electrospray ionization were used to evaluate the isomeric heterogeneity of neutral oligosaccharide-Alditols isolated from bovine submaxillary mucin (BSM). The oligosaccharide-Alditol mixture was preseparated on an off-line high-performance liquid chromatography (HPLC) column, and the structural homogeneity of individual LC fractions was investigated using a Synapt G2 traveling wave ion mobility spectrometer coupled between quadupole and time-of-flight mass spectrometers. Mixtures of isomers separated by both chromatography and ion mobility spectrometry were studied. Tandem mass spectrometry (MS/MS) of multiple mobility peaks having the same mass-to-charge ratio (m/z) demonstrated the presence of different structural isomers and not differences in ion conformations due to charge site location. Although the oligosaccharide-Alditol mixture was originally separated by HPLC, multiple ion mobility peaks due to structural isomers were observed for a number of oligosaccharide-Alditols from single LC fractions. The collision-induced dissociation cells located in front of and after the ion mobility separation device enabled oligosaccharide precursor or product ions to be separated by ion mobility and independent fragmentation spectra to be acquired for isomeric carbohydrate precursor or product ions. MS/MS spectra so obtained for independent mobility peaks at a single m/z demonstrated the presence of structural variants or stereochemical isomers having the same molecular formula. This was observed both for oligosaccharide precursor and product ions. In addition, mobilities of both [M – H]− and [M + Cl]− ions, formed by adding NH4OH or NH4Cl to the electrospray solvent, were examined and compared for selected oligosaccharide-Alditols. Better separation among structural isomers appeared to be achieved for some [M + Cl]− anions
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evaluation of ion mobility mass spectrometry for determining the isomeric heterogeneity of oligosaccharide Alditols derived from bovine submaxillary mucin
International Journal of Mass Spectrometry, 2013Co-Authors: Brad Bendiak, William F. Siems, Kimberly Kaplan, Eric J Davis, Herbert H. HillAbstract:Rapid separation and independent analysis of isomeric species are needed for the structural characterization of carbohydrates in glycomics research. Ion mobility-mass spectrometry techniques were used to examine a series of isomeric neutral oligosaccharide-Alditols derived from bovine submaxillary mucin. Several analytical techniques were employed: (1) off line separation of the oligosaccharide-Alditol mixture by HPLC; (2) direct and rapid evaluation of isomeric heterogeneity of oligosaccharides by electrospray ionization-ion mobility-time of flight mass spectrometry; and (3) mobility-selected MS2 and MS3 to evaluate isomeric mobility peaks by dual gate ion mobility-tandem mass spectrometry. Multiple isomeric ion mobility peaks were observed for the majority of oligosaccharide-Alditols, which was achieved on the millisecond time scale after LC separation. Fragmentation spectra obtained from the collision-induced dissociation of isomeric precursor ions could be essentially identical, or dramatically different for a given precursor m/z using the dual-gate ion mobility quadrupole ion trap mass spectrometer. This further confirmed the need for rapid physical resolution of isomeric precursor species prior to their tandem mass spectral analysis.
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.
Brad Bendiak - One of the best experts on this subject based on the ideXlab platform.
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Determining the isomeric heterogeneity of neutral oligosaccharide-Alditols of bovine submaxillary mucin using negative ion traveling wave ion mobility mass spectrometry.
Analytical chemistry, 2015Co-Authors: Brad Bendiak, William F. Siems, David R. Gang, Herbert H. HillAbstract:Negative ions produced by electrospray ionization were used to evaluate the isomeric heterogeneity of neutral oligosaccharide-Alditols isolated from bovine submaxillary mucin (BSM). The oligosaccharide-Alditol mixture was preseparated on an off-line high-performance liquid chromatography (HPLC) column, and the structural homogeneity of individual LC fractions was investigated using a Synapt G2 traveling wave ion mobility spectrometer coupled between quadupole and time-of-flight mass spectrometers. Mixtures of isomers separated by both chromatography and ion mobility spectrometry were studied. Tandem mass spectrometry (MS/MS) of multiple mobility peaks having the same mass-to-charge ratio (m/z) demonstrated the presence of different structural isomers and not differences in ion conformations due to charge site location. Although the oligosaccharide-Alditol mixture was originally separated by HPLC, multiple ion mobility peaks due to structural isomers were observed for a number of oligosaccharide-Alditols f...
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Determining the Isomeric Heterogeneity of Neutral Oligosaccharide-Alditols of Bovine Submaxillary Mucin Using Negative Ion Traveling Wave Ion Mobility Mass Spectrometry
2015Co-Authors: Brad Bendiak, David R. Gang, William F. Siems, Herbert H. HillAbstract:Negative ions produced by electrospray ionization were used to evaluate the isomeric heterogeneity of neutral oligosaccharide-Alditols isolated from bovine submaxillary mucin (BSM). The oligosaccharide-Alditol mixture was preseparated on an off-line high-performance liquid chromatography (HPLC) column, and the structural homogeneity of individual LC fractions was investigated using a Synapt G2 traveling wave ion mobility spectrometer coupled between quadupole and time-of-flight mass spectrometers. Mixtures of isomers separated by both chromatography and ion mobility spectrometry were studied. Tandem mass spectrometry (MS/MS) of multiple mobility peaks having the same mass-to-charge ratio (m/z) demonstrated the presence of different structural isomers and not differences in ion conformations due to charge site location. Although the oligosaccharide-Alditol mixture was originally separated by HPLC, multiple ion mobility peaks due to structural isomers were observed for a number of oligosaccharide-Alditols from single LC fractions. The collision-induced dissociation cells located in front of and after the ion mobility separation device enabled oligosaccharide precursor or product ions to be separated by ion mobility and independent fragmentation spectra to be acquired for isomeric carbohydrate precursor or product ions. MS/MS spectra so obtained for independent mobility peaks at a single m/z demonstrated the presence of structural variants or stereochemical isomers having the same molecular formula. This was observed both for oligosaccharide precursor and product ions. In addition, mobilities of both [M – H]− and [M + Cl]− ions, formed by adding NH4OH or NH4Cl to the electrospray solvent, were examined and compared for selected oligosaccharide-Alditols. Better separation among structural isomers appeared to be achieved for some [M + Cl]− anions
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evaluation of ion mobility mass spectrometry for determining the isomeric heterogeneity of oligosaccharide Alditols derived from bovine submaxillary mucin
International Journal of Mass Spectrometry, 2013Co-Authors: Brad Bendiak, William F. Siems, Kimberly Kaplan, Eric J Davis, Herbert H. HillAbstract:Rapid separation and independent analysis of isomeric species are needed for the structural characterization of carbohydrates in glycomics research. Ion mobility-mass spectrometry techniques were used to examine a series of isomeric neutral oligosaccharide-Alditols derived from bovine submaxillary mucin. Several analytical techniques were employed: (1) off line separation of the oligosaccharide-Alditol mixture by HPLC; (2) direct and rapid evaluation of isomeric heterogeneity of oligosaccharides by electrospray ionization-ion mobility-time of flight mass spectrometry; and (3) mobility-selected MS2 and MS3 to evaluate isomeric mobility peaks by dual gate ion mobility-tandem mass spectrometry. Multiple isomeric ion mobility peaks were observed for the majority of oligosaccharide-Alditols, which was achieved on the millisecond time scale after LC separation. Fragmentation spectra obtained from the collision-induced dissociation of isomeric precursor ions could be essentially identical, or dramatically different for a given precursor m/z using the dual-gate ion mobility quadrupole ion trap mass spectrometer. This further confirmed the need for rapid physical resolution of isomeric precursor species prior to their tandem mass spectral analysis.
Miloudi Hlaibi - One of the best experts on this subject based on the ideXlab platform.
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carbohydrate resorcinarene complexes involved in the facilitated transport of Alditols across a supported liquid membrane
Journal of Membrane Science, 2011Co-Authors: Miloudi Hlaibi, Nabila Tbeur, Abdelkhalek Benjjar, Oussama Kamal, Laurent LebrunAbstract:Abstract A supported liquid membrane (SLM) containing a resorcinarene carrier has been used for the selective transports of arabinitol and perseitol from concentrated aqueous solutions (0.2–0.025 M). Maltitol and lactitol, two Alditols derived from disaccharides, were also studied. The membrane is made of a microporous poly(tetrafluoroethylene) film impregnated with a 0.01 M solution of the carrier in CCl4. The permeabilities of the SLM for all Alditols were calculated. For each Alditol, the initial flux is related to initial concentration in the feed phase by a saturation law, indicating that the rate-determining step in the transport mechanism is the migration of a (1/1) carrier–carbohydrate complex in the immobilized organic phase. Using a model previously published, the apparent diffusion coefficients D* and the stability constants K of the carrier–Alditol complexes were determined. The magnitudes of the stability constants are related to the structures of the Alditols, particularly to the number and orientation of hydroxyl groups that interact with the carrier. In small Alditols that contain an arabino triol system, the site of binding to the carrier is the erythro diol group. In the large molecules of disaccharides and perseitol in which more OH groups are available, more stable carrier–Alditol complexes are formed: it is believed that two remote sites of binding interact with two independent recognition sites of the carrier. Aim To understand the nature of chemical recognition between the carrier and polyols.
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Carbohydrate–resorcinarene complexes involved in the facilitated transport of Alditols across a supported liquid membrane
Journal of Membrane Science, 2011Co-Authors: Miloudi Hlaibi, Nabila Tbeur, Abdelkhalek Benjjar, Oussama Kamal, Laurent LebrunAbstract:Abstract A supported liquid membrane (SLM) containing a resorcinarene carrier has been used for the selective transports of arabinitol and perseitol from concentrated aqueous solutions (0.2–0.025 M). Maltitol and lactitol, two Alditols derived from disaccharides, were also studied. The membrane is made of a microporous poly(tetrafluoroethylene) film impregnated with a 0.01 M solution of the carrier in CCl4. The permeabilities of the SLM for all Alditols were calculated. For each Alditol, the initial flux is related to initial concentration in the feed phase by a saturation law, indicating that the rate-determining step in the transport mechanism is the migration of a (1/1) carrier–carbohydrate complex in the immobilized organic phase. Using a model previously published, the apparent diffusion coefficients D* and the stability constants K of the carrier–Alditol complexes were determined. The magnitudes of the stability constants are related to the structures of the Alditols, particularly to the number and orientation of hydroxyl groups that interact with the carrier. In small Alditols that contain an arabino triol system, the site of binding to the carrier is the erythro diol group. In the large molecules of disaccharides and perseitol in which more OH groups are available, more stable carrier–Alditol complexes are formed: it is believed that two remote sites of binding interact with two independent recognition sites of the carrier. Aim To understand the nature of chemical recognition between the carrier and polyols.
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Molecular recognition of carbohydrates by a resorcinarene. Selective transport of Alditols through a supported liquid membrane.
Carbohydrate research, 2000Co-Authors: Nabila Tbeur, Miloudi Hlaibi, Touria Rhlalou, Dominique Langevin, Michel Metayer, Jean-françois VerchèreAbstract:Abstract A supported liquid membrane (SLM) containing a resorcinarene carrier has been used for the selective transport of erythritol, threitol, ribitol and xylitol from concentrated (1.0–0.01 M) aqueous solutions. The membrane is made of a microporous polytetrafluoroethylene film impregnated with a 0.01 M solution of the carrier in CCl 4 . The permeabilities of the SLM for all Alditols were calculated. On the basis of the flux dependence on the initial concentrations of carrier and Alditol, the rate-determining step in the transport mechanism is shown to be the migration of the 1:1 carrier–carbohydrate complex in the immobilized organic phase. The flux of sugar is related to the initial concentration of Alditol in the feed phase by a saturation law, which allowed the determination of the apparent diffusion coefficients and the stability constants of the resorcinarene complexes of Alditols formed in the liquid membrane.