Expedient Synthesis of a Library of Heparan Sulfate‐Like “Head‐to‐Tail” Linked Multimers for Structure and Activity Relationship Studies

Heparan sulfate (HS) plays important roles in many biological processes. The inherent complexity of naturally existing HS has severely hindered the thorough understanding of their structure‐activity relationship. To facilitate biological studies, a new strategy has been developed to synthesize a HS‐like pseudo‐hexasaccharide library, where HS disaccharides were linked in a “head‐to‐tail” fashion from the reducing end of a disaccharide module to the non‐reducing end of a neighboring module. Combinatorial syntheses of 27 HS‐like pseudo‐hexasaccharides were achieved. This new class of compounds bound with fibroblast growth factor 2 (FGF‐2) with similar structure‐activity trends as HS oligosaccharides bearing native glycosyl linkages. The ease of synthesis and the ability to mirror natural HS activity trends suggest that the new head‐to‐tail linked pseudo‐oligosaccharides could be an exciting tool to facilitate the understanding of HS biology. New heparan sulfate (HS) mimetics were synthesized where the disaccharide modules were connected from the reducing end to the non‐reducing end to mimic the structures of native polysaccharides more closely. A library of 27 such “head‐to‐tail” pseudo‐hexasaccharides was prepared, which was found to exhibit similar structure‐activity relationship trends as HS hexasaccharides in the binding to fibroblast growth factor 2.