Tetraosyl hexapeptide, a part of the sequence of betaglycan: beta-D-GlcA-(1-->3)-beta-D-Gal-(1-->3)-beta-D-Gal-(1-->4)-beta-D-Xyl-(1-->O-SerGlyTrpProAspGly (1), which was designed as a probe for glycan elongation toward heparin, was synthesized in a stereocontrolled manner. (C) 2002 Elsevier Science Ltd. All rights reserved.