The application of 2,2,2-trichloroethyl sulfate to the synthesis of chondroitin sulfate C and D.

Chondroitin sulfates (CSs) have characteristic bioactivities that depend on sulfation patterns. Chemically synthesized CS oligosaccharides are valuable tools for elucidating the relationship between structures and bioactivities. 2,2,2-Trichloroethyl (TCE) sulfated sugars are highly soluble in nonpolar solvents, which is useful for the synthesis of sulfated oligosaccharides. We herein synthesized CS-C [βGalNAc6S(1-4)βGlcA] (1) and CS-D [βGalNAc6S(1-4)βGlcA2S] (2) disaccharides that possessed sulfate groups by TCE sulfation at O-6 of GalNAc and an additional sulfate group at O-2 of GlcA, respectively. We revealed the superior functionalities of TCE sulfates during the synthesis of CS-C and -D, despite the unwanted side reactions in the acetamido-containing substrate.