5346-73-6Relevant academic research and scientific papers
The preparation and the assignment of the 1H and 13C NMR spectra of methylated derivatives of inulin oligosaccharides
Timmermans,Bogaert,De Wit,Vliegenthart
, p. 1145 - 1158 (1997)
The complete assignment of the 1H and 13C NMR spectra for permethylated sucrose, 1-kestose and nystose are given. Methylation of these inulin oligosaccharides did not change the conformation of the ring structures. A partially methylated derivative of nystose has been prepared using water as the solvent. The difference in reactivity of the various hydroxyl groups of nystose appeared to be very small.
Identification of fungal trehalose for the diagnosis of invasive candidiasis by mass spectrometry
Cornu, Marjorie,Fran?ois, Nadine,Guerardel, Yann,Jawhara, Samir,Martinez-Esparza, Maria,Mery, Alexandre,Poissy, Julien,Poulain, Daniel,Sendid, Boualem
, (2022/01/24)
The rapidity of the diagnosis of invasive candidiasis (IC) is crucial to allow the early introduction of antifungal therapy that dramatically increases the survival rate of patients. Early diagnosis is unfortunately often delayed because Candida blood culture, the gold standard diagnostic test, is positive in only 50% of cases of IC and takes several days to obtain this result. Complementary non-culture-based methods relying on the detection of Candida cell wall polysaccharides in the serum, β-glucans and mannans, by enzymatic and immunological reagents have been successfully developed to allow a more efficient patients care. We have previously demonstrated that detection of circulating glycans by mass spectrometry could provide a reliable and cost-effective early diagnosis method called MS-DS for Mass Spectrometry of Di-Saccharide. Here, by comparing patient's sera and Candida albicans strains deficient in carbohydrates synthesis, we demonstrate that trehalose derived from fungal metabolism can be specifically targeted by MS-DS to allow early diagnosis. In particular, the use of C. albicans strains deficient in the synthesis of trehalose synthesizing enzymes Tps1 and Tps2 show that MS-DS results were correlated to the metabolism of trehalose. Finally, we demonstrate that the performance of the IC diagnosis can be significantly improved by using high resolution mass spectrometry, which opens new perspectives in the management of the disease.
A novel methylation derivatization method for δ18O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry
Lehmann, Marco M.,Fischer, Maria,Blees, Jan,Zech, Michael,Siegwolf, Rolf T. W.,Saurer, Matthias
, p. 221 - 229 (2016/01/09)
Rationale The oxygen isotope ratio (δ18O) of carbohydrates derived from animals, plants, sediments, and soils provides important information about biochemical and physiological processes, past environmental conditions, and geographical origins, which are otherwise not available. Nowadays, δ18O analyses are often performed on carbohydrate bulk material, while compound-specific δ18O analyses remain challenging and methods for a wide range of individual carbohydrates are rare. Methods To improve the δ18O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry (GC/Pyr-IRMS) we developed a new methylation derivatization method. Carbohydrates were fully methylated within 24 h in an easy-to-handle one-pot reaction in acetonitrile, using silver oxide as proton acceptor, methyl iodide as methyl group carrier, and dimethyl sulfide as catalyst. Results The precision of the method ranged between 0.12 and 1.09‰ for the δ18O values of various individual carbohydrates of different classes (mono-, di-, and trisaccharides, alditols), with an accuracy of a similar order of magnitude, despite high variation in peak areas. Based on the δ18O values of the main isomers, important monosaccharides such as glucose and fructose could also be precisely analyzed for the first time. We tested the method on standard mixtures, honey samples, and leaf carbohydrates extracted from Pinus sylvestris, showing that the method is also applicable to different carbohydrate mixtures. Conclusions The new methylation method shows unrivalled accuracy and precision for δ18O analysis of various individual carbohydrates; it is fast and easy-to-handle, and may therefore find wide-spread application.
Peralkylation of Saccharides under Aqueous Conditions
Wang, Hui,Sun, Lihong,Glazebnik, Serge,Zhao, Kang
, p. 2953 - 2956 (2007/10/02)
Treatment of saccharides with sodium hydroxide and alkyl halides in aqueous dimethyl sulfoxide solution offers a very efficient method for the complete alkylation of saccharides in high yields.
STRUCTURE OF PENTA-O-ACETYLSUCROSES FORMED BY DEACETYLATION OF OCTA-O-ACETYLSUCROSE. REACTION OF 2,3,4,6,6'-PENTA-O-ACETYLSUCROSE
Capek, Karel,Vydra, Tomas,Sedmera, Petr
, p. 1317 - 1332 (2007/10/02)
Chromatographic separation of penta-O-acetylsucrose fraction from deacetylation of octa-O-acetylsucrose by treatment with aluminum oxide impregnated by potassium carbonate gave-1',3,4,6,6'-penta-O-acetylsucrose (XII), 1,2,3,4,6-penta-O-acetylsucrose (XIII), and the prevailing-2,3,4,6,6'-penta-O-acetylsucrose (XIV).Reaction of compound XIV with two equivalents of p-toluenesulfonyl chloride in pyridine produced besides the 1'-O-p-toluenesulfonyl derivative XXI and 1',3',4'-tri-O-tosyl derivative XXII also 1',3'-di-O-tosyl derivative XXIII and 1',4'-di-O-tosyl derivativeXX. 1',2-anhydro(3,4,6-tri-O-acetyl-α-D-glucopyranosyl 6'-O-acetyl-3',4'-anhydro-β-D-ribo-hexulofuranoside) (X) and 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-D-ribo-hexulofuranoside (VIII) were prepared from compound XXIII by two minutes boiling with 1M sodium methoxide, evaporation of the reaction mixture, and acetylation (method A).Compound XX gives under reaction conditions of method A 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-D-lyxo-hexulofuranoside (IX) only.However, upon 24 h boiling with 1M sodium methoxide, neutralization, evaporation, and acetylation of the reaction mixture (method B), we obtained 3,3',4,6,6'-penta-O-acetyl-1',2-anhydro-4'-O-methylsucrose (XXIV), 1',2,3,3',4,6,6'-hepta-O-acetyl-4'-O-methylsucrose (XXV), and 1',2-anhydro-(3,4,6-tri-O-acetyl-α-D-glucopyranosyl 3',4',6'-tri-O-acetyl-β-D-xylo-hexulofuranoside) (XXVI).Compounds XXV and XXVI are also formed by reaction of epoxide IX with sodium methoxide according to method B.Compound XXVI can be prepared by hydrolysis of the dianhydro derivative X followed by acetylation.A reaction mechanismfor compound XXVI formation from the epoxide IX is proposed.It assumes an intramolecular opening of the oxirane ring in compound IX under formation of α-D-glucopyranosyl 1,3-anhydro-β-D-xylo-hexulofuranoside (XLVI).The 1'-O-tosyl derivative XXI reacts with sodium methoxide according to method B to give 3,3',4,4',6,6'-hexa-O-acetyl-1',2-anhydrosucrose (XXVIII), octa-O-acetylsucrose, and 2,3,3',4,6,6'-hexa-O-acetyl-1',4'-anhydrosucrose XL.
A new catalyst for reductive cleavage of methylated glycans.
Jun,Gray
, p. 247 - 261 (2007/10/02)
Several per-O-methylated D-glucans and D-fructans were used as models in an attempt to identify new catalysts for carrying out reductive cleavage. Included in these model studies were several D-glucans that contained 4-linked D-glucopyranosyl residues as well as one having a 4-linked D-glucitol residue, as both types of residue had previously been found to give rise to substantial proportions of artifactual products. These studies led to the development of a new catalyst for carrying out reductive cleavage, namely, a mixture of 5 equivalents of trimethylsilyl methanesulfonate (Me3SiOSO2Me) and 1 equivalent of boron trifluoride etherate (BF3 . Et2O) per equivalent of acetal. This new catalyst was found to accomplish the reductive cleavage of per-O-methylated, 4-linked D-glucopyranosyl residues and 4-linked D-glucitol residues, to give only the expected derivatives of 1,5-anhydro-D-glucitol and D-glucitol, respectively. The mixture of Me3SiOSO2Me and BF3 . Et2O also catalyzed reductive cleavage of the D-fructofuranosyl residues of per-O-methylated sucrose and inulin, to give only the expected derivatives of 2,5-anhydro-D-mannitol and 2,5-anhydro-D-glucitol. Indeed, when used alone, Me3SiOSO2Me also rapidly catalyzed the reductive cleavage of D-fructofuranosyl residues, but, under the same conditions, D-glucopyranosyl residues were unaffected. The results of these and other model studies demonstrated that catalysis of reductive cleavage by the mixture of Me3SiOSO2Me and BF3 . Et2O occurs in a synergistic manner. Examination of the mixture of Me3SiOSO2Me and BF3 . Et2O by 1H-n.m.r. spectroscopy demonstrated that a reaction occurs to generate trimethylsily fluoride and species of the type F2BOSO2Me, FB(OSO2Me)2, or B(OSO2Me)3 via ligand exchange.
