Synthesis of -D-Galf-(1→3)-D-GlcNAc by the tricloroacetamidate method and of -D-Galf-(1→6)-D-GlcNAc by SnCl4-promoted glycosylation

CAROLA GALLO -RODRIGUEZ; LUCÍA GANDOLFI; R. M. DE LEDERKREMER

ORGANIC LETTERS

AMER CHEMICAL SOC

Lugar: Washington; Año: 1999 vol. 1 p. 245 - 247

1523-7060

In a continuation of our studies on the characterization of the glycoproteins of T. cruzi new galactofuranosyl disaccharides were synthesized.â-D-Galf-(1-3)-D-GlcNAc (1) was prepared by employing the trichloroacetamidate procedure for the glycosylation step. The mild conditions of this reaction are appropriate for condensation of 2,3,5,6-tetra-O-benzoyl-â-D-galactofuranosyl trichloroacetamidate (6) with acid-labile benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-r-D-glucopyranoside (3). On the other hand, tin(IV) chloride promoted condensation of benzyl 2-acetamido-3-O-benzoyl-2-deoxy-r-D-glucopyranoside (11) with penta-O-benzoyl-r,â-D-galactofuranose (4) gave the derivative of â-D-Galf-(1-6)-D-GlcNAc(2) in 78% yield.