Azido-sugars

Owing to flexibility in the substrate, the TycATE was also used to synthesize a variety of novel cyclic structures. Inclusion of a propargylated amino acid into the linear substrate allowed the synthesis of over 247 macrocyclic glycopeptides, where azido-sugars were coupled onto the cyclized alkyne via copper-catalyzed 1,3-dipolar cycloaddition [44] (Figure 13.12). 

Scheme 26. Alkylation of fulleropentathiol by an alkyne spacer followed by click chemistry with various azido sugars, including the Pk trisaccharide.235...

Wash the cells at least twice with 0.1 percent fetal bovine serum in 10mM sodium phosphate, 0.15M NaCl, pH 7.4 (PBS) to remove excess azido-sugar. 

Add to the washed cells 60 pi of a 5 mM concentration of the phosphine derivative to couple to the azido-sugar groups on the cell surface (e.g., biotin-PEG-phosphine). 

Oxidation is a general method for the preparation of nitro sugars from other sugar derivatives, as amino or azido sugars and sugar oximes. 

Guthrie and Irvine35 also developed an original synthesis of unsaturated isothiocyanates, starting from a mixture of the unsaturated azido sugars 15... 

P. A. M. van der Klein, W. Filemon, G. H. Veeneman, G. A. van der Marel, and J. H. van Boom, Highly regioselective ring opening of five-membered cyclic sulfates with lithium aluminium azide synthesis of azido sugars, J. Carhohydr. Chem., 11 (1992) 837-848. 

T. Uryu, K. Hatanaka, K. Matsuzaki, and H. Kuzuhara, Synthesis of stereoregular polysaccharides having amino-groups by ring-opening copolymerization of 1,6-anhydro-azido-sugar derivatives, J. Polym. Sci., Part A Polym. Chem., 21 (1983) 2203-2214. 

D. C. Baker and D. Horton, Photolysis of azido sugar derivatives. Generation of aldehydes from 5 -azido derivatives of adenoside and uridine, Carbohydr. Res., 21 (1972) 393 105. 

Scheme 3.10 Preparation of azido sugars by nucleophilic substitution.

Recently, Wong et al. (54) have reported the synthesis of a small, 24-member focused library of aminoglucopyranosides (LI, Fig. 8.9) inspired by the structure of paromomycin, a known aminoglycoside antibiotic (8.18, Fig. 8.7). A retrosynthetic study identified the azido sugar 8.19 as the key intermediate for the library synthesis its preparation on a multigram scale is also given in Fig. 8.9. 

Laughlin, S. T., Agard, N. J., Baskin, J. M., et al. (2006). Metabolic labeling of glycans with azido sugars for visualization and glycoproteomics. Methods Enzymol., 415, 230-250. 

Prescher, J. A., Dube, D. H., Bertozzi, C. R. (2003). Probing azido sugar metabolism in vivo using the Staudinger ligation. Glycobiology, 13, 894. 

One synthesis of the important anti-viral drug AZT 163 (Azidothymidine, used in the treatment of HIV) shows this. The doubly silylated thymine 161 combines with the azido-sugar 162 under Lewis acid catalysis to give AZT after work-up. Only 33% of the required diastereoisomer 163 can be isolated and about the same amount of the other is formed.18... 

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