Sugar thiourea

Sugar thioureas can be prepared, conversely, by nucleophilic addition of the amino group of amino sugars to alkyl and aryl isothiocyanatcs. Since the... 

The more characteristic spectroscopic feature of sugar thioureas is the, 3C NMR chemical shift, of the thiocarbonyl carbon atom at 180-185 ppm. 

Fig. 6 Postulated seven- (A) and six-membered intramolecular hydrogen bonds (B) in sugar thioureas.

An impressive number of papers has appeared in the past few years based on the use of sugar thioureas as intermediates in the synthesis of the naturally occurring potent trehalase inhibitor trehazolin (251) and of several isomers.52 396-404 The key reaction step involved the cyclization of an A,iV-disubstituted a-D-glucopyranosyl-aminocyclitol (a-D-glucopyranosyl-... 

J. M. Garda Fernandez, C. Ortiz Mellel, J. L. Jimenez Blanco, J. Fuenles, M. Martin-Paster, and J. Jimenez-Barbero, Macrocyelic sugar thioureas Cyclocligosaecliarides mimicking cyclopeptides, in Molecular Recognition and Inclusion. A. W. Coleman (Ed.), Kluwer, Dordrecht, 1998. 103-108. 

Sugar-thiourea receptors were also studied to probe possibility of long-range hydrogen bonds in supramolecular helbc formation. This type of foldamers were shown to form intramolecular 15-membered hydrogen bonds between thiourea NH and sugar 05ygen atom (Fig. 7). 

Fig. 7 Schematic representation of helix uncoiling in sugar-thiourea anion receptors by carboxylate binding.

The synthesis of imidazo[2,l-h]thiazolium-3-olate zwitterions such as (100) from sugar thiourea derivatives, and their cycloaddition reactions to form imidazo[l,2-fl]pyridin-4-ones such as (101) (Scheme 10) have been detailed. ... 

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