Alditols spectroscopy

Preliminary examinations of dextran structures were conducted by optical rotation, infrared spectroscopy and periodate-oxidation reactions. More detailed results can be achieved by methylation analysis [19]. The hydroxyl groups are methylated with methyl iodide after activation with sodium methylsulfinyl carbanion (Fig. 2). The methyl dextran is hydrolysed to the corresponding different methylated monosaccharides, which are furthermore reduced and peracetylated. The resulting alditol acetates of methylated sugars are separated by gas chromatography and identified by their retention times. In particular, a combined capillary gas-liquid chromatography/mass... 

Amino acid analysis of a strong acid hydrolysate (2 N HCl at 100° C for 3 h) identified only glutamic acid and this was confirmed by gas chromatography-mass spectroscopy (Fig. 4). Mild acid hydrolysis (0.5 N HCl at 80°C for 1 h) followed by direct insertion mass spectroscopy gave a spectrum identical to authentic ribose-5-phosphate (Fig. 5). Borate electrophoresis of the alditol derived from the stored material and of its acid... 

Usually, the methylated sugars are derivatized to alditol acetates and separated by GC combined with mass spectroscopy (60-63). 

Methyl 2,2, 3,3 4, 6 -hexamethyl-j8-maltoside (4) has been converted to the mixture of alditol glycosides (5) as outlined in Scheme 1, which can form the basis of a method for the specific degradation of uronic acid-containing polysaccharides, mass spectrometry showing the site of linking, and n.m.r. spectroscopy the glycosidic configuration. ... 

High-Resolution H-Nuclear Magnetic Resonance Spectroscopy of Oligosaccharide-Alditols Released from Mncin-Type O-Glycoproteins... 

The oxidation of alditols and methyl glycopyranosides, etc. with sodium metaperiodate in deuterium oxide has been followed by n.m.r. spectroscopy ... 

In a first application of pattern recognition to n.m.r. spectroscopy by a neural network, the H-n.m.r. spectra of six alditols have been assigned. Analysis of the preferred conformations of partially acetylated alditols In CDQ3 showed that they are mainly determined by intramolecular hydrogen-bonding between the firee hydroj groups. ... 

Fractionation of extracts of Convolvulus glomeratus afforded a new branched-chain alditol, 2-C-methyl-D-erythritol, whose constitution and absolute configuration were deduced by and n.m.r. spectroscopy, c.d. measurements, and synthesis. ... 

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