A novel regioselective desulfation of polysaccharide sulfates: specific 6-O-desulfation with N,O-bis(trimethylsilyl)acetamide
✍ Scribed by Masayoshi Matsuo; Ryo Takano; Kaeko Kamei-Hayashi; Saburo Hara
- Book ID
- 102991473
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 494 KB
- Volume
- 241
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
Treatment of the pyridinium salts of glycosaminoglycans and galactan sulfates with N,O-bis(trimethylsilyl)acetamide (BTSA) in pyridine for 2 h at 60 "C caused specific 6-O-desulfation without depolymerisation or other chemical changes.
Introduction
Polysaccharide sulfates are present in most algal cell matrices, and those of animal origin are also well-known as mucopolysaccharides. Various methods for desulfation have been developed and one of the convenient methods involves dilute methanolic hydrogen chloride, as applied originally to chondroitin sulfate'. However, this method causes considerable depolymerisation and reduction in yield because of concomitant cleavage of glycosidic linkages. A better yield of the desulfated polysaccharides without serious decomposition can be obtained by solvolysis of the pyridinium salts in such aprotic solvents as methyl sulfoxide, N,N-dimethylformamide, and pyridine', or methyl sulfoxide containing a small amount of water or methano13-5. The mechanism of the reaction is envisaged as a reverse of sulfation. Another advantage of solvolytic desulfation is that selective N-desulfation can be achieved by careful control of the reaction conditions3. However, versatile regiospecific chemical methods of 0-desulfation are not known and sulfatases with any site specificity are rarely available. Therefore, the development of a method for specific 0-desulfation would be of value in the elucidation of the biological activity of sulfated carbohydrates.