Sulfated sugars (sugar sulfuric acid esters) are very common representatives of biologically active molecules (glycosaminoglycans, carbohydrate ligands). These esters are rather unstable from a biological point of view, because they can be cleaved by different esterases or sulfatases. Surprisingly, only one - enzymatically stable - sugar C-sulfonic acid has been found in the Nature; it is the 6-deoxy-6-sulfo-D-glucopyranose, that exists in different diacyl-glycerol forms (1). These substances are constituents of the membranes of all photosynthetic organisms and show strong anticancer, antiviral and anti-HIV activities. Many syntheses of the 6-deoxy-6-sulfo-D-glucopyranose have been accomplished, but sugars having secondary sulfonic acid function have not been described to date. The aim of our group was to synthesize sugar sulfonic acids (14, 17 and 26) and sugar methylene sulfonic acids (28, 34, 42, 44), the latter compounds are bioisosteric with the sugar sulfates. Different methods were applied for the preparation of thiosugars, like nucleophilic displacement reactions (26), migration of 1,2-trans-1-thio-2-O-sulfonyl pyranosides (12 and 15) to 1,2-trans-2-thiotrityl glycosides (13 and 16) followed by oxidation to 2-C-sulfonic acids (14 and 17) either by oxone or H2O2. Methylene sulfonic acids were prepared using free radical addition of either HSAc (38 and 39) or NaHSO3 (42 and 44) to sugar-exomethylene groups situated in different position of pyranosides. Sugar sulfoulosonic acids (28) and their 2-thioglycosides (29) were also prepared and used for the syntheses of complex oligosaccharides which could be ligands (34) of adhesion proteins (selectins) or human pathogenic bacteria (Helicobacter pylori).
|Number of pages||4|
|Journal||Magyar Kemiai Folyoirat, Kemiai Kozlemenyek|
|Publication status||Published - Jun 1 2004|
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