title: Synthesis and preliminary characterisation of charged derivatives and hydrogels from scleroglucan.
abstract: The synthesis of negatively and positively charged polyelectrolytes from scleroglucan is described. Polycarboxylates were synthesised through nucleophilic substitution with chloroacetic acid or through a selective 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO)-mediated oxidation of the primary alcohol groups. Amine groups were introduced through nucleophilic substitution with 2-chloroethylamine or 3-chloropropylamine. Reaction conditions were varied to obtain insight into the influence of variables on the degree of substitution. The conformational behaviour of the obtained polyelectrolytes was studied as a function of pH, temperature and solvent. For the products with a low degree of modification, evidence of an ordered conformation was found, whereas the polymers with a higher degree of modification behaved as random coils in solution. The negatively charged polymers were reticulated using the Ugi four-component condensation, obtaining negatively charged hydrogels. The positively charged polymers were reticulated using diethyl squarate (3,4-diethoxy-3-cyclobutene-1,2-dion, DES) to obtain positively charged hydrogels.
authors.affiliation: Department of Chemistry, University La Sapienza, Rome, Italy.
authors.forename: A E
authors.initials: AE
authors.lastname: de Nooy
authors.forename: V
authors.initials: V
authors.lastname: Rori
authors.forename: G
authors.initials: G
authors.lastname: Masci
authors.forename: M
authors.initials: M
authors.lastname: Dentini
authors.forename: V
authors.initials: V
authors.lastname: Crescenzi
mesh_terms: D000042:Absorption; D000085:Acetates; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D003432:Cross-Linking Reagents; D003497:Cyclic N-Oxides; D004573:Electrolytes / Q000138:chemical synthesis / Q000737:chemistry; D005936:Glucans / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008745:Methylation; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012997:Solvents; D055672:Static Electricity; D013696:Temperature
chemical_list: D000085:Acetates; D003432:Cross-Linking Reagents; D003497:Cyclic N-Oxides; D004573:Electrolytes; D005936:Glucans; D020100:Hydrogels; D012997:Solvents; C045938:scleroglucan; C006972:chloroacetic acid; C003959:TEMPO