The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Ying Gai - One of the best experts on this subject based on the ideXlab platform.
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Optimized GC-MS Method To Simultaneously Quantify Acetylated Aldose, Ketose, and Alditol for Plant Tissues Based on Derivatization in a Methyl Sulfoxide/1-Methylimidazole System
2016Co-Authors: Shichang Liu, Yupeng Tan, Nan Chao, Xiaoming Tian, William A. Powell, Xiangning Jiang, Ying GaiAbstract:The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different aldoses and Ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates aldose, ketose, and alditol can be determined simultaneously by GC-MS
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Optimized GC-MS method to simultaneously quantify acetylated aldose, ketose, and alditol for plant tissues based on derivatization in a methyl sulfoxide/1-methylimidazole system.
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Shichang Liu, Yupeng Tan, Nan Chao, Xiaoming Tian, William A. Powell, Xiangning Jiang, Ying GaiAbstract:The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different aldoses and Ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates aldose, ketose, and alditol can be determined simultaneously by GC-MS.
Rainer Mahrwald - One of the best experts on this subject based on the ideXlab platform.
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cascade reactions of unprotected Ketoses with ketones a stereoselective access to c glycosides
European Journal of Organic Chemistry, 2016Co-Authors: Celin Richter, Michael Krumrey, Kristin Klaue, Rainer MahrwaldAbstract:A highly stereoselective de-Bruyn–Ekenstein rearrangement/aldol condensation/intramolecular oxa-Michael cascade reaction of unprotected Ketoses with ketones was elaborated. By the utilization of this new and operationally simple methodology an access to β-C-glycosides is given. Extremely matched and mismatched cases were observed by using with natural or unnatural proline in these cascade reactions.
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Amine-catalyzed cascade reactions of Ketoses with 1,3-dicarbonyl compounds
RSC Advances, 2015Co-Authors: Celin Richter, Benjamin Voigt, Rainer MahrwaldAbstract:An amine-catalyzed cascade reaction of Ketoses with 1,3-dicarbonyl compounds is described. Several highly chemo- as well as stereoselective reactions are operating in this novel cascade. The operationally simple protocol allows stereoselective access to optically active carbon chain elongated Ketoses.
Shuichi Osanai - One of the best experts on this subject based on the ideXlab platform.
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PREPARATION OF 2-HYDROXYMETHYLATED ALDOSE BY THE STEREOSPECIFIC REARRANGEMENT OF KETOSE
Bulletin of the Chemical Society of Japan, 1995Co-Authors: Ryoji Yanagihara, Jun Egashira, Sadao Yoshikawa, Shuichi OsanaiAbstract:A simple one-stage reaction system which yields 2-C hydroxymethylated aldopentose has been investigated. Four different 2-C branched aldopentoses (2-C hydroxymethylated D-arabinose, D-ribose (Hamamelose), L-lyxose, and D-xylose) were prepared from the corresponding Ketoses (D-psicose, D-fructose, L-sorbose, and D-tagatose, respectively). These branched sugars were synthesized by a similar mechanism to the 2-C epimerization of aldose using a nickel complex. It was confirmed that the isomerization of ketose to the side-branched sugar proceeded in the ternary nickel complex through a sequence of stereospecific rearrangements in the sugar. The yields were dependent upon the structure of the substrate ketose and the nickel-ethylenediamine complex. N,N′-Dialkylated cyclohexanediamines were the most suitable ligands for preparing the 2-C hydroxymethylated branched chain sugar.
Shichang Liu - One of the best experts on this subject based on the ideXlab platform.
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Optimized GC-MS Method To Simultaneously Quantify Acetylated Aldose, Ketose, and Alditol for Plant Tissues Based on Derivatization in a Methyl Sulfoxide/1-Methylimidazole System
2016Co-Authors: Shichang Liu, Yupeng Tan, Nan Chao, Xiaoming Tian, William A. Powell, Xiangning Jiang, Ying GaiAbstract:The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different aldoses and Ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates aldose, ketose, and alditol can be determined simultaneously by GC-MS
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Optimized GC-MS method to simultaneously quantify acetylated aldose, ketose, and alditol for plant tissues based on derivatization in a methyl sulfoxide/1-methylimidazole system.
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Shichang Liu, Yupeng Tan, Nan Chao, Xiaoming Tian, William A. Powell, Xiangning Jiang, Ying GaiAbstract:The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different aldoses and Ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates aldose, ketose, and alditol can be determined simultaneously by GC-MS.
Celin Richter - One of the best experts on this subject based on the ideXlab platform.
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cascade reactions of unprotected Ketoses with ketones a stereoselective access to c glycosides
European Journal of Organic Chemistry, 2016Co-Authors: Celin Richter, Michael Krumrey, Kristin Klaue, Rainer MahrwaldAbstract:A highly stereoselective de-Bruyn–Ekenstein rearrangement/aldol condensation/intramolecular oxa-Michael cascade reaction of unprotected Ketoses with ketones was elaborated. By the utilization of this new and operationally simple methodology an access to β-C-glycosides is given. Extremely matched and mismatched cases were observed by using with natural or unnatural proline in these cascade reactions.
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Amine-catalyzed cascade reactions of Ketoses with 1,3-dicarbonyl compounds
RSC Advances, 2015Co-Authors: Celin Richter, Benjamin Voigt, Rainer MahrwaldAbstract:An amine-catalyzed cascade reaction of Ketoses with 1,3-dicarbonyl compounds is described. Several highly chemo- as well as stereoselective reactions are operating in this novel cascade. The operationally simple protocol allows stereoselective access to optically active carbon chain elongated Ketoses.
