Dimethylformamide → Azide

Participants

Reaction Steps

An azide functionalized ATRP initiator (azidepropyl 2-bromoisobutyrate, AzPBIB) was prepared by the esterification reaction of azide propanol with α-bromoisobutyryl bromide in anhydrous THF at 0° C. for overnight. AzPBIB was then introduced to alkyne-functionalized PEG copolymer via click chemistry. In a typical procedure, poly(OEGMA-co-PgTEGMA) (0.1 g, 0.09 mmol based on alkyne groups), AzPBIB (9.2 mg, 0.037 mmol), CuBr (5.3 mg, 0.037 mmol), PMDETA (6.4 mg, 0.037 mmol) and DMF (0.5 mL) were added to a Schlenk tube. The reaction tube was degassed by three freeze-pump-thaw cycles, sealed under vacuum, and placed in a 40° C. oil bath for 24 h. After cooling to room temperature, the flask was exposed to air. After removing most of the solvents at reduced pressure, the residues were dissolved in DCM and passed through a neutral alumina column to remove copper catalysts. The solution was then concentrated under reduced pressure and precipitated in hexane. The isolated polymer poly(OEGMA-co-PgTEGMA-co-BIBTEGMA) was dried under vacuum. The bromoisobutyrate ratio in the final copolymer is approximately 12% as determined by 1H NMR analysis.

Provenance & Evidence