Polysaccharides acetylated, chromium trioxide

Oxidation of PI with chromium trioxide. Fraction PI was twice acetylated as described above. The peracetylated polysaccharide (75 mg), together with 20 mg of mannitol hexacetate as internal standard was dissolved in 1.5 mL of HCCI3, and treated with 1.89 mL of glacial acetic acid and 189 mg of chromium trioxide, at 50°C. Aliquots were removed at zero, 30, 60 and 120 min, water then added, and the material recovered by extraction with chloroform, hydrolyzed and analysed by GLC of derived alditol acetates. 

The anomeric configurations of the sugar residues were determined by chromium trioxide oxidation [14], Oxidation of the fully acetylated polysaccharide and subsequent monosaccharide analysis by GLC indicated that the D-Xyl units are P-linked (oxidized more rapidly) and that die D-GlcA are a-linked (Table II). 

---