Synthesis of Functional Rare Monosaccharide 2,3-Diamino-D-mannuronic Acids

OBJECTIVE To synthesize two functional 2,3-diamino-D-mannuronic acid glycosides for investigating their structure-activity relationships and biomedical applications.

METHODS Starting with allyl D-allose as the starting material, the key intermediate 3-azido-D-glucuronic acid was synthesized by performing a nucleophilic substitution of the S_N2 azide group at the C3 position and oxidizing the hydroxyl group at the C6 position. Subsequently, two target products were obtained by reactions involving linker assembly, nucleophilic substitution of the azide group at the C2 position, reduction of the azide group, and selective modification of the amino group through acetamidino and acetyl groups.

RESULTS The structures of all intermediates and target products were confirmed using ¹H-NMR, ¹³C-NMR, and HRMS, with the products purity exceeding 99.0% as determined by HPLC.

CONCLUSION The synthetic route for these two functional rare glycosides is straightforward and the resulting products exhibit high purity, laying a solid foundation for future investigations into their immunological activities.