Mannose trimethylsilyl ethers

Fig. 27. Gas-liquid chromatogram of the separation of trimethylsilyl ethers of sugars on hexamethyldisilazane-treated Chromosorb W (80-100 mesh) coated with 15% (w/w) Carbowax 20M. Column 12 foot X % inch copper coil 170° helium 100 ml per minute 4 /il of 02% solution. Peaks 1, ribose 2, ribose 3, a-mannose 4, y-galactose 5, a-galactose 6, internal standard 7, a-glucose 8, yS-mannose 9, /3-galactose 10, 8-glucose. Reproduced from Sawardeker and Sloneker (S2) with permission.

The presence of 2,3,4- and 2,4,6-tri-O-methyl-D-mannoses had been overlooked in earlier work in which the separation of the methyl mannosides had been attempted on Apiezon M. When the methyl glycosides were separated as their trimethylsilyl ethers on Carbowax 6000, resolution of the 2,3,4, 2,4,6, and 3,4,6 isomers was achieved. Bauer and coworkers have continued with the application of this method in their work on yeast mannans. 

Bhattacharjee and Gorin utilized trimethylsilyl derivatives of methyl maimosides in a model study on mannose ethers, and recommended these compounds for the separation of the dimethyl isomers in particular. Handa and Montgomery likewise used trimethylsilyl ethers in a study of the partial methylation of methyl a-o-mannopyranoside, and Choy and Unrau gave similar data for 2,3,6- and 2,4,6-tri-O-methyl-n-mannose. 

In a model study on the methyl ethers of n-mannose, the 2,3,4,6-and 2,3,5,6-ethers, as well as the 2,5,6- and 3,5,6-tri-O-methyl-D-mannoses, were best distinguished as the trimethylsilyl derivatives of the free sugars, and Gray and Ballou used these derivatives in their examination of a mannan from Mycobacterium phlei. 

The g.l.c. separation of various methylated derivatives of mannose, galactose, and glucosamine as their trimethylsilylated derivatives has been described using 0.3-0.4% OV 225 on Chromosorb that had been surface modified by a high molecular weight polyethylene glycol. Conditions have been found for the separation of the TMS ethers of arabinose, xylose, mannose, ot- and /3-glucose, fructose, sorbose, xylitol, mannitol, and sorbitol on Chromosorb W-NAW with 15% Carbowax 20M, and a g.l.c. method for the quantitative determination of trehalose as its TMS ether has been reported." ... 

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