Synthesis of Hyperbranched Carbohydrate Polymer by Ring-Opening Multibranching Polymerization of 1,4-Anhydroerythritol and 1,4-Anhydro-l-threitol

Abstract

1,4-Anhydroerythritol (1a) and 1,4-anhydro-L-threitol (1b) were polymerized using trifluoromethanesulfonic acid (CF3SO3H) or fluorosulfonic acid (FSO3H) as a cationic initiator. The polymerizations of 1a and 1b proceeded through a ring-opening reaction with a proton-transfer reaction to produce hyperbranched carbohydrate polymers (2a and 2b) mainly consisting of erythritol and L-threitol units, respectively. The degrees of branching (DB) estimated by the 13 C NMR spectra of 2a and 2b were ca. 0.28-0.47. The weight-average molecular weight (Mw,SLS) values (3.2 × 10 4 -5.1 × 10 5 ) estimated using static laser light scattering (SLS) of the resulting hyperbranched carbohydrate polymers were significantly higher than the weight-average molecular weight (Mw,SEC) values (1.5 × 10 3 -1.4 × 10 4 ) estimated using size exclusion chromatography (SEC). The solution viscosities of 2a and 2b were very low, and the intrinsic viscosities ([η]) of 2a and 2b were in the range from 3.26 × 10 -2 to 7.30 × 10 -2 dL‚g -1 . The three-dimensional properties characterized by the SLS and viscosity measurements indicated that 2a and 2b should be nanoscale particles.

Synthesis of Hyperbranched Carbohydrate Polymers by Ring‐Opening Multibranching Polymerization of Anhydro Sugar

“…In this section, we introduce the ring-opening multibranching polymerization of 1,4-anhydroerythritol (4a) and 1,4-anhydro-Lthreitol (4b) using trifluoromethanesulfonic acid (CF 3 SO 3 H) or fluorosulfonic acid (FSO 3 H), as shown in Scheme 2. [45] The bulk polymerizations of 4a and 4b were carried out using CF 3 SO 3 H or F 3 SO 3 H. After the initiator was added to the monomer, the polymerization proceeded homogeneously, and the viscosity of the polymerization systems immediately increased as the polymerization progressed. The resulting product was a white powdery polymer, which was soluble in water, sparingly soluble in methanol, and insoluble in other organic solvents.…”

“…[45] Therefore, it is important to synthesize and characterize hyperbranched polytetritol without any anhydrotetritol unit. In this section, we introduce the synthesis of a hyperbranched carbohydrate polymer essentially consisting of tetritol units by the ring-opening multibranching polymerization of 2,3-anhydroerythritol (9a) and 2,3-anhydro-DL-threitol (9b), [48] which are the structural isomers of 1,4-anhydrotetritol (4a and 4b), as shown in Scheme 5.…”

“…Because the ring strains of the oxirane-type monomers of 9a and 9b were larger than those of the tetrahydrofuran-type monomers of 4a and 4b, the polymerizations of 9a and 9b led to hyperbranched polytetritols without the 2,3-anhydrotetritol units, although the hyperbranched carbohydrate polymers prepared from 4a and 4b contained 1,4-anhydrotetritol units. [45] Monomers 9a and 9b have an epoxy group and two hydroxy groups in the molecule, so that they are classified as latent AB 3 -type monomers. The DBs estimated by the 13 5b varied in the range of 0.28 to 0.47, the DBs of 10a and 10b did not change according to the polymerization condition.…”

Hyperbranched aliphatic polyether polyols

“…Several other anhydrosugars have been polymerized in the following years. 53,54,[93][94][95][96][97][98] Anhydrosugars containing a tetrahydrofuran scaffold are rather expensive monomers. Therefore, the group of Bednarek and Kubisa focused on the polymerization of tetrahydrofurans substituted with hydroxyl groups, mainly 2-(hydroxymethyl)tetrahydrofuran, but also 3-hydroxytetrahydrofuran and 3,4-dihydroxytetrahydrofuran.…”

Determination of molecular size and shape of hyperbranched polysaccharide in solution

“…[2][3][4][5] The periphery of dendrimer molecules has many end groups that can be functionalized and used as sites for further chemistry or to interact in a specific manner with their surroundings. Recently, hyperbranched polysaccharides [6][7][8][9] have been prepared by the acid-catalyzed ring-opening polymerization and cationic polymerization. These synthetic biopolymers have many end groups such as -OH or -NH 2 and adopt spherical molecular architectures in aqueous solution.…”