Synthesis of branched polysaccharides by ring-opening polymerization of anhydro-oligosaccharide derivatives

摘要

Many polysaccharides in nature play an important role in the specific biological activities such as antitumor, immunoaduvant, and antiviral activities originated from their specific structures. However, it is difficult to elucidate the relationship between the structure and biological activities of natural polysaccharides because of their complex structures. There are three reports so far on the synthesis of comb-shaped branched polysaccharides by the ring-opening polymerization of anhydro-disaccharide monomers such as 1,6-anhydro-maltose, -cellobiose, and -mannobiose. We also reported the polymerization of permethylated 1,6-anhydro-lactose to give methylated 4-O-β-D-galactopyranosyl-(1→6)-α-D-glucopyranan with a high molecular weight of M_n = 347 x 10~3. However, there are no reports on the polymerization of anhydro trisaccharide monomers. In the work presented here, for the synthesis of new branched polysaccharides having a defined structure, we will describe the synthesis of branched ribofuranans by ring-opening polymerization of new 1,4-anhydro ribo-oligosaccharide monomers.