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:[β??d??GlcA??(1→ 3)?螃漫?d??Gal??(1→ 3)?螃漫?d??Gal??(1→ 4)?螃漫?d??Xyl?? (1→ O)??Ser??Gly] was synthesized by glycosylation of the corresponding tetraosyl ...