Synthesis of Thiosugars

Thiosugars constitute another class of carbohydrate analogs presenting interesting biological and pharmacological properties [105, 106]. 

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Stereocontrolled synthesis of thiosugars from acyclic precursors and preparation of pseudonucleosides with thiosugar moiety 97YGK186. 

Le Merrer, Y, Fuzier, M, Dosbaa, I, Foglietti, M-J, Depezay, J-C, Synthesis of thiosugars as weak inhibitors of glycosidases. Tetrahedron, 53, 16731-16746, 1997. 

Witczak, Z. J. Chhabra, R. Chen, H. Xie, X. Q., Thiosugars.2. A novel approach to thiodisaccharides - The synthesis of 3-deoxy-4-thiocellobiose from levoglucosenone. 

Scheme 48 Synthesis of butenolides fused to pento- or hexopyranoses and thiosugar analogs from furanos-3-nloses...

Being restricted to DHAP as the nucleophile, aldol additions will only generate ketoses and derivatives from which aldose isomers may be obtained by biocatalytic ketol isomerization (cf. Sect. 7.1) [306]. For a more direct entry to aldoses the inversion strategy may be followed (Scheme 19) [290] which utilizes monoprotected dialdehydes. After aldolization and stereoselective chemical or enzymatic ketone reduction, the remaining masked aldehyde function is deprotected to provide the free aldose. Further examples of the directed, stereodivergent synthesis of sugars and related compounds such as aza- or thiosugars are collected in Sect. 7. 

K. Yamamoto, M. Haga, and S. Tejima, Thiosugars. 18. Synthesis of 2-acylamino-... 

Chem. Soc. Chem. Commun. 1983, 835-836. Witczak, Z. J. Boryczewski, D. Thiosugars IV design and synthesis of S-linked fiicoside analogs as a new class of a-L-fucosidase inhibitors. Bioorg. Med. Chem. Lett. 1998, 8, 3265-3268. Kim, K. S. Hurh, E. Y. Youn, J. N. Park, J. I. Dialkyl (l-hydroxyiminoalkyl)phosphonates from 1-bromo-l-nitroalkanes and trialkyl phosphites./. Org. Chem. 1999, 64, 9272-9274. 

Thiosugars can be rapidly synthesized when sulfur-substituted aldehydes are condensed with DHAP under the influence of FDP aldolase.42 The synthesis of these heterocycles is completed by phosphate cleavage, acetylation and reduction of the resultant ketone (Scheme 5.20). Cyclitols, another interesting class of biologically active compounds, have been prepared through the reaction of phosphonate- and nitro-substituted aldehydes with DHAP under the influence of FDP aldolase (Scheme 5.21) 43,436... 

Tsuruta O, Yuasa H, Hashimoto H, Sujino K, Otter A, Li H, Palcic MM. Synthesis of GDP-5-thiosugars and their use as glycosyl donor substrates for glycosyltransferases. J. Org. Chem. 2003 68 6400-6406. 

Phosphorus dithioacids [RR P(S)SH] are effective sulfur nucleophiles for the synthesis of 3 -S-or 5 -5 -nucleosides [107]. Furthermore, Mitsunobu reactions have also been used to convert primary sugar alcohols into corresponding thiosugar derivatives in one-pot manner [108]. 

J. M. Lacombe, N. Rakotomanomana, and A. A. Pavia, Free-radical addition of 1-thiosugars to alkenes. A new general approach to the synthesis of 1-thioglycosides, Tetrahedron Lett., 29 (1988) 4239-4296. 

Thiosugars. 1. Synthesis of Derivatives of 2-Amino-2-deoxy-l-thio-D-glucose, D. Horton and M. L. Wolfrom,/. Org. Chem., 27, 1794-1800 (1962). 

Fluorination of 4-thiofuranose hydroxyl-containing derivatives by dialkylamino sulfur trifluoride was successfully applied for the synthesis of 2-fluoro-4-thiosugars 127,128." "" The reactions proceed with complete retention of C-F carbon atom configuration. 

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