Synthesis and preliminary characterisation of charged derivatives and hydrogels from scleroglucan.
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.
de Nooy
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Department of Chemistry, University La Sapienza, Rome, Italy.
Rori
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Masci
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Dentini
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Crescenzi
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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
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