Syntheses of Cellulose-Type Polysaccharide by Means of Ring-Opening Copolymerization of Anhydroriboses ABRP and AIRP

Two kinds of 1,4-anhydroribose derivatives, 1,4-anhydro 2,3-O-benzylidene-α-D-ribopyranose （ABRP） and 1,4-anhydro 2,3-O-isopropylidene α D ribopyranose （AIRP） were prepared from D-ribose. The ring-opening copolymerizations of ABRP and AIRP in various feed ratios were carried out with SbCl₅ and BF₃OEt₂ as catalyst at low temperatures. The copolymer structure was characterized by means of ¹H,¹³C NMR spectroscopy and specific rotation. When SbCl₅ was used as catalyst, the copolymer obtained had completely 1,4-β-pyranosidic structure, i.e., cellulose type structure. However, when BF₃OEt₂ was used as catalyst, the copolymer had a mixed structure of furanosidic and pyranosidic units.