Deoxy Thioglycosides

The chiral epoxide (50), obtained by Sharpless asymmetric eposidation of a racemic alkene, has been converted into the 2-deoxy-thioglycosides (51), which were obtained as a 1 1 anomeric mixture (Scheme 10) the a-thioglycoside was used in the... 

The oxidation of the a-amino acids has not been completely studied, but it appears to be slow in most cases.8-9 The organic sulfide linkage is oxidized by periodate to a sulfone, with the concomitant liberation of iodine,48 but the oxidation of a 1-deoxy-l-thioglycoside, without occurrence of this side reaction, has been carried out at least once (in very dilute solution).44... 

Scheme 5.48 CaCI3-promoted formation of 2-deoxy-P-thioglycosides.

An amidrazone (58) derived from 5-amino-5-deoxy-L-fuconolactam was found to inhibit a recombinant human a-L-fucosidase with a K -value of 820 nmol/1 [ 111 ]. A simple synthesis of 1,5-dideoxy-1,5-imino-D-arabinitol (59), previously prepared by Ganem et al. [49] as a potential maimosidase inhibitor, was applied to the affinity purification of a-L-fucosidase from bovine kidney by an improved method and the characterization of the enzyme thus obtained [112]. The relatively low affinity of this compound to the enzyme (Kj 2.2 pmol/1 at pH 7) compared to 1-deoxyfuconoJirimycin (51) turned out to be advantageous in terms of enzyme recovery and yield. Structurally related, suitably protected 5-amino-5-deoxy-D-arabinopyranose (60), was coupled with a N-acetyl-6-deoxy-6-thio-D-glucosaminide (61) to give a stable thioglycoside (62) [113]. 

Scheme 8). Treatment of a variety of 3-ammo-3-deoxy sugars with ethanethiol leads not only to diethyl dithioacetals, but also to varying amounts of thioglycoside products... 

The manno thioglycoside 55 on treatment with DAST give the 2-deoxy-2-phenyl-thio-glucosyl fluoride as anomeric mixture 56. On glycosylation with the 6-hydroxy-glucoside 57 in dichloromethane and the presence of SnCl2, the ot,l- 6 disaccharide 58 is obtained exclusively (92%), which on reduction with Raney-Nickel yields the 2 -deoxy derivative 59. 

The phenyl L-thioglycoside of the axenose donor 186 was synthesized from the methyl 2-deoxy-D-eryt/zro-pentofuranoside 185 (Scheme 54). 

S. Paul and N. Jayaraman, Catalytic ceric ammonium nitrate mediated synthesis of 2-deoxy-1-thioglycosides, Carbohydr. Res., 339 (2004) 2197-2204. 

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