Synthesis of Glycoconjugates Containing a 1,2,3-Triazole Unit

The glycoconjugates have an enormous potential in drug design¹. Between them, glycopeptides are particularly important as they combine the structural features of amino acids and carbohydrates in the same molecule. Glycoconjugates containing the 1,2,3-triazole unit find application in medicinal chemistry, particularly in those cases where this unit acts as a bridge between an amino acid/peptide and the sugar moiety. In this work the synthesis of several glycoconjugates containing the 1,2,3-triazole unit as a bridge between a sugar (D-glucose) moiety and an amino acid or heteroaromatic unit is described. The starting alkynyl esters were prepared by reaction between N-protected glycine, tyrosine and phenylalanine, 7-hydroxycoumarin and 7-hydroxy-4-methylcoumarin and propargyl bromide with high yields. The 1,2,3-triazole unit was formed by an azide-alkyne 1,3-dipolar cycloaddition, catalysed by a Cu(I) species, a chemical process usually known as click chemistry.^2,3The azido component was prepared in situ from a-acetobromoglucose. The precursors and the final compounds were characterized by usual methods. Thanks to FCT, Portugal for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho) and to FCT and FEDER -COMPETE-QREN-EU for financial support to the Research Centre, CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)] References 1. C. Böttcher, J. Spengler , S.A. Essawy, K. Burger, Monastshefte für Chemie, 2004, 135, 853-863. 2. F. Himo, T. Lovell, R. Hilgraf, V. V. Rostovtsev, L. Noodleman, K. B. Sharpless, V. V. Fokin, J. Am. Chem. Soc., 2005, 127, 210-216. 3. R. Kumar, P.R. Maulik, A.K. Misra, Glycoconj. J., 2008, 6, 1898-1901.