Synthesis of phosphorylated and sulfated glycosyl serines in the linkage region of the glycosaminoglycans.

We synthesized novel acidic glycans having acidic groups located in the linkage region of the glycosaminoglycans (GAGs). The targeted compounds, beta-D-Xyl(2P)-Ser (1), beta-D-Gal(+/-6S)-(1-->4)-beta-D-Xyl(2P)-Ser (3 and 2), beta-D-Gal(+/-6S)-(1-->3)-beta-D-Gal-(1-->4)-beta-D-Xyl(2P)-Ser (5 and 4), and beta-D-Gal-(1-->3)-beta-D-Gal(6S)-(1-->4)-beta-D-Xyl(2P)-Ser (6) contain phosphate and/or sulfate at the specified positions. Some of them (3, 5, and 6) are the first synthesized examples of natural-type glycoconjugates that simultaneously possess phosphate and sulfate as well as carboxylic acid.