Neoglycoconjugates of antigenic oligosaccharides. Synthesis of Galp(alpha1,3)Galp(beta1,4)GlcNAc-L-Threo.

POKLEPOVICH CARIDE, S; AGUSTI, R.; LEDERKREMER, R.M.; MARINO, C

Buenos Aires

Simposio; 1ª Simposio argentino de Glicobiología; 2014

Sociedad Argentina de Glicobiologia

Oligosaccharides from Trypanosoma cruzi mucins present particular structures. For example the presence of alpha-Galp in trypomastigotes and beta-Galf in epimastigotes and metacyclic of salvage strains is unique, being both configurations immunogenic. On the other hand, while protein mucins present extense polymorphism, the sugar structures have a characteristic pattern which depends not only of the stage but also of the strain. The presence of antibodies against saccharidic epitopes plays a relevant role in the infection. Synthetic oligosaccharides and their conjugates are used for the diagnostic of several diseases. We describe here preliminary studies for the synthesis of Galp(alpha1,3)Galp(beta1-4)GlcNAc-N-threo (1), containing the minimum antigenic oligosaccharidic structure found in trypomastigote mucins of chronic chagasic patients. We proposed the use of 2,3,4,6-tetra-O-benzyl-alpha-D-Galp trichloroacetimidate (2), tolyl 4-O-acetyl-2-benzoyl-6-O-tertbutyldiphenylsilyl-beta-D-1-thio-Galp (4) and 6-O-tertbutyldiphenylsilyl-2-acetamido-2-deoxy-D-Glcp-L-Threo (5) as building blocks, with the aim of establish an efficient high yielding procedure for such synthesis and thus produce glycoconjugate 1 in the high amount and the low cost required for its clinic use . Studies about the regioselective glycosylation of 5 and spectroscopical characterization of synthetic intermediates will be present.