Ethyl isocyanatoacetate → Dihexyl aspartate carbamate

Participants

Reaction Steps

2.7 g (i.e., 50 mmol of hydroxyls) of dextran with a weight-average molar mass of approximately 10 kg/mol (Bachem) are dissolved in a DMF/DMSO mixture. The mixture is brought to 130° C. with stirring and 3.2 g (25 mmol) of ethyl isocyanatoacetate and then 3.9 g (8 mmol) of dihexyl 2-isocyanatobutanedioate are gradually introduced. After reacting for 1 h, the medium is diluted in water and purified by diafiltration through a 5 kD PES membrane against 0.1N NaOH, 0.9% NaCl and water. The final solution is quantitatively determined by dry extract, in order to determine the concentration of polymer. A fraction of solution is lyophilized and analyzed by 1H NMR in D2O in order to determine the degree of conversion of the hydroxyls to N-(sodium methylcarboxylate) carbamate and the degree of the functionalization of the hydroxyls to give dihexyl aspartate carbamate.

Provenance & Evidence