Synthetic approach toward the partial sequences of betaglycan in the linkage region on solid support and in solution phase

We have synthesized, for the first time, the partial sequence of the betaglycan composed of the tetraosyl hexapeptide, which was directly usable as a probe for enzymatic glycosyl transfer. Stepwise elongation afforded the corresponding tetraosyl trichloroacetimidate. The common glycosyl dipeptide:[beta-D-GlcA-(1 -> 3)-beta-D-Gal-(1 -> 3)-beta-D-Gal-(1 -> 4)-beta-D- Xyl-(1 -> O)-Ser-Gly] was synthesized by glycosylation of the corresponding tetraosyl trichloroacetimidate and Ser-Gly moiety. The glycosyl dipeptide was coupled with other core peptide parts in solution phase and on a solid support. These glycosyl hexapeptides were then transformed into the desired target compounds.