Glucose 1-thio

Under acidic conditions, benzylated l,6-anhydro-/J-D-glucose (1) was also used as a donor with 4-thio-glucose (2 a) or 4 -thiomaltose derivatives (2 b) and the condensation afforded a-linked thio-di (3 a) or trisaccharides (3 b) in fair yields [6] (Scheme 1). It is noteworthy that 1,6-anhydro-di- and trisaccharide are unreactive under these conditions. 

Thioglucobioses (69a) and (70a) were easily prepared from 2-0-triflyl-man-nose tetraacetate (68) and 1-thio-glucoses (8a) or (10b). However, Zemplen 0-deacetylation led to an intractable mixture of compounds. Thus, prior to methoxide treatment, the readily cleavable allyl group was introduced at the anomeric position (Scheme 22) [20] of the acetylated disaccharides (69a) and (70a). Benzyl -thiokojibioside (70c) was also prepared by condensation of (68) and (16a) [29bj. 

In the area of glucosinolate chemistry, sinigrin 76, has been made by methods suitable for a ten gram reaction, starting with 4-nitrobut-l-ene and 1-thio-glucose 2,3,4,6-tetra-O-acetate, and a similar approach was adopted in the preparation of the methylthioalkyl analogue 11 ... 

One of the most unusual carbohydrate - amino acid linkages so far found in Nature is the thio linkage between glucose or galactose and cysteine.35,40 41 This glycopeptide has not yet been isolated or synthesized. Therefore, in order to obtain 13C-n.m.r. chemical-shift data for... 

Kamp, F. P. van de, u. F. Micheel Uber D-Glucose-Derivative von Thio-semicarbazonen und ihre biologische Wirksamkeit. Chem. Ber. 89, 133 (1956). 

A Michael addition-Nef reaction sequence was used in a synthesis of disaccharides. Addition of the sodium salt of 1-thio-D-glucose to sugar nitroolefin 112 gave a mixture of isomers 113. The subsequent deacetylation, followed by a Nef reaction, afforded the S -disaccharides 114 and 115 (Scheme 35).82... 

Tetraacetyl-l-thio-/S-D-glucose to tetraacetyl-l,5-anhydro-i>-glueitol 2.4 U (t tl <4 — 17... 

Synthese der 2-Thio-D-glucose und einiger 3-Thio-D-altrose-Derivate, by E. Hardegger and W. Schiiep, Helv. Chim. Acta, 53 (1970) 951-959. 

Versuche zur Synthese der 4-Thio-D-glucose, by L. Vegh and E. Hardegger, Helv. Chim. Acta, 56 (1973) 1792-1799. 

Procedure 3 Glucose-isomerase-catalysed Isomerization of 5-Thio-d-xylulofuranose to 5-Thio-d-xylopyranose... 

M. S. Feather and R. L. Whistler, Derivatives of 5-thio-D-glucose, Tetrahedron Lett., 3 (1962)... 

Several methods were described for the selective de-S-acetylation of 0-acetyl protected 1-thioglycoses. Sodium methoxide in methanol at low temperature (below -20 °C) was known to afford mainly the de-S-acetylated compound [16] or exclusively this compound when the reaction was quenched at low temperature by adding H-l- resin [17]. Demercuration of tetra-O-acetyl-l-phenylmercury(II)-thio- -D-glucopyranose (12) (Scheme 4) obtained by treatment of (8e) with phenylmercury(II)acetate afforded a convenient synthesis of tetra-0-acetyl-l-thio-/3-D-glucose (8a) [18]. This sequence applied to the a-anomer (10a) (Scheme 3) led to the expected de-S-acetylated compound (10b) [19]. Chemoselective deprotection of thioacetate at the anomeric position of peracetylated 1-thioglycoses was also achieved in good yield by action of cysteamine in acetonitrile or hydrazinium acetate in DMF [20,11]. 

A new method of stereoselective synthesis of thiodisaccharides by conjugate addition of 1-thio- D-glucose (8a) or 1-thio-a-L-fucose (30b) to an imsatura-ted carbohydrate molecule was also used for the preparation of o-glucopyrano-syl- and of L-fiicopyranosyl-thiodisaccharides [56]. 

The sulfonium salts are readily available by alkylation of a thio derivative of D-glucose. When the R1 and R2 groups are different, diastereomeric mixtures on the sulfur atom are obtained in some cases, which cannot be separated by recrystallization. 

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