Thio-oligosaccharides

SCHEME 14.18 Hindsgaul s solid-phase synthesis of thio-oligosaccharides. 

Hummel, G, Hindsgaul, O, Sohd-phase synthesis of thio-oligosaccharides, Angew. Chem. Lnt. Ed., 38, 1782-1784, 1999. 

Conformational equilibria of thio-oligosaccharides revealed that the most important thiodisac-charide (4-thio-a-maltoside) has a conformation similar to that of the parent maltosyl residue and that the thioglycoside linkage presents a high degree of flexibility. Interestingly, the C-S... 

Also, thioacetic acid can be used as nucleophile in this approach, to give anomeric thioacetates, which, in a two step-procedure, can be selectively S-deacylated and alkylated to give thioglycosides, a sequence often used in the synthesis of thio-oligosaccharides [25]. 

We have presented an exhaustive and up to date review on the synthesis of thio-oligosaccharides which can be used to probe interactions with proteins. The ease of synthesis of this class of molecule should furnish new tools for glycobiochemists and glycobiologists. 

The replacement of the interglycosidic ojgrgen by a sulphur atom leads to thio-oligosaccharides, which have been used as glycosidase inhibitors. Calle et al. have addressed the conformational distortion in the molecular recognition process by p-galactosidases from Escherichia coli of... 

A cysteine residue was incorporated into the protein backbone in a specific position and activated to thioglycosylation by treatment with phenylselenenyl bromide. The electrophilic character of the sulphur atom in the resulting S-Se bond makes possible its nucleophilic substitution by 1-thio mono- or oligosaccharides (Fig. 26).55... 

Fan, L. F. Hindsgaul, O., Synthesis of novel cyclic oligosaccharides beta-l,6-thio-linked cycloglucopyranosides. Org. Lett. 2002,4, 4503-4506. 

Reaction of peracetylated l-thio-a-o-glucopyranose (10a) with peracetylated 6-deoxy-6-iodomaltose (18), 6 -deoxy-6 -iodomaltose (21a) and 6 -deoxy-6 -iodomalto-oligosaccharides (21 b,21 c) gave the corresponding S-a-glucosylthio-maltose derivatives (20,23a-c) in excellent yields (Scheme 7) [24,28,29aj. 

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