Preparation of High Polymers from 1,6-Anhydro-2,3,4-tri-O-Substituted β-D-Glucopyranose

Ring-Opening Polymerization of a Benzylated 1,6-Anhydro-β-d-talopyranose and Synthesis of a New Polysaccharide, (1→6)-α-d-Talopyranan

“…As shown in Table 1, when the concentration of PF 5 was lower than 5 mol % relative to the monomer, a trace amount of polymer was obtained (entries 1 and 2). Increasing the concentration to 10 mol % PF 5 gave polymers with M n =15 500-19 600 in 8 to 22% yields (entries [3][4][5][6][7][8]. At 20 mol % PF 5 , the yield was slightly improved, but the M n of the polymers was decreased (entries 3 and 9, 4 and 10, 5 and 11, 6 and 12).…”

“…Ring-opening polymerization and copolymerization were carried out by a high-vacuum technique at -60 or -80°C as described in the literature, 6 except that a magnetic stirring bar was used in the polymerization ampule. Purification and isolation of the resulting polymer also followed a published method 6 Debenzylation 1 . A solution of 2 (100 mg, M n = 17 500, M w / M n =2.5) in dry 1,2-dimethoxyethane (3 mL) was dropped into a solution of sodium (0.6 g) in liquid ammonia (50 mL) with stirring at -78°C under nitrogen.…”

Preparation and Analysis of Cello- and Xylooligosaccharides

“…The ringopening polymerization of 1,6-anhydro-2,3,4-tri-O-benzyl derivatives of monomeric β-D-pyranosides had been studied in the same laboratory in earlier years [23][24][25][26][27][28], and investigators managed to stereoselectively synthesize oligo-and polysaccharides of relatively high DPs . In this context, the temperature at which polymerization took place as well as the choice of Lewis acid had a strong impact on the DP finally reached and the stereoselectivity of the prolongation reaction [24,28]. With this experience, the authors managed to build derivatized product polymers out of the 1,6-anhydro-cellobiose benzyl ether derivative, with number average molecular weights of 6-7 Â 10 3 g mol À1 .…”

Sulfated Polysaccharides as Specific Biologically Active Materials

“…The ring-opening polymerization of anhydro sugar derivatives into stereoregular polysaccharides was first reported by Schuerch in 1966, who prepared benzylated 1, 6-anhydro-β-D-glucopyranose (LGTBE) 1 and polymerized it using phosphorus pentafluoride (PF5) as a cationic catalyst under high vacuum to give (1→6)-α-D-glucopyranan 3 after reductive deprotection of benzyl groups to recover hydroxyl groups by sodium in liquid ammonia, as shown in Scheme 1 (3). The yield and molecular weight of polymers produced by the ring-opening polymerization were high.…”