Depolymerization of glycosaminoglycuronans into di- and higher molecular-weight oligo-saccharides: Improved preparation of N-acetyldermosine and oligomeric N-acetylchondrosines

Nonsulfated di- to octadeca-saccharides having 2-acetamido-2-deoxy-d-galactose at the reducing end were prepared, in 81% yield, by treatment of chondroitin 6-sulfate (pyridinium salt) with dimethyl sulfoxide containing 10% of water for 14 h at 90°. N-Acetylchondrosine and N-acetyldermosine were obtained from dermatan sulfate of rooster comb, in 30% and 38% yields, respectively, by solvolysis with dimethyl sulfoxide, containing 10% of water, for 30 h at 105°. Hyaluronic acid was also depolymerized by the same solvent in the presence of an equimolar amount of pyridinium sulfate or chloride per disaccharide unit to give reducing di- and higher molecular weight oligo-saccharides. The results of solvolytic desulfation and depolymerization are compared with those of the conventional methods by acid hydrolysis.