Sugars oximes, acetyl derivatives

Oximes can be reduced to amino-sugars with a variety of reagents. Dlborane reduction of the acetylated oxime (l8), derived from L-rhamnal, gave access to methyl N-trifluoroacetyl a-L-acosamlnlde... 

Partially methylated, acetylated aldononitriles are acyclic derivatives readily formed from reducing sugars by reaction with hydroxylamine in pyridine, followed by the addition of acetic anhydride to effect elimination of acetic acid from oxime acetates and acetylation of unsubstituted hydroxyl groups. These derivatives, although less extensively used, appear to give good GLC separations, and their mass spectra can be readily interpreted without the problem of structural symmetry (75MI3). 

Sugars, being nonvolatile, must be converted to volatile derivatives before GC analysis is possible. During the 1970s and 1980s, many different methods of derivatization were explored, but most of the novel procedures were not pursued further. The derivatization methods that have been generally adopted as standard procedures for GC analysis of sugars of various types include conversion to acetylated alditols or aldononitriles, oximation followed by acetylation, trimethylsilylation or trifluoroacetylation. 

The simultaneous g.c.-(e.i.)m.s. analysis of sugars (aldoses, ketoses, sugar acids, oligosaccharides and alditiols), carboxylic acids and phosphoric acid as their pertrimethylsiylated oxime derivatives has been optimized and applied to the analysis of over 40 such components in apple varieties. G.c.-m.s. analysis of carbohydrates as their acetylated 0-methyloxime derivatives was particularly useful for application to glycoconjugates of plant origin. ... 

A g.l.c. procedure that establishes the DP of oligo- and poly-saccharides has been developed. The oligo(poly)saccharide was reduced prior to hydrolysis and conversion of the reducing sugars liberated into their oxime derivatives the DP was determined from the ratio of acetylated aldononitrile to acetylated alditol. A similar technique, which determined the ratio of aldose acetate to alditol acetate, was used to measure the DP of amylose. ... 

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