| 内容提要: |
The excess 4,4-Azodianiline (0.212 g, 1.2 mmol) was weighted and added in 3 mL of anhydrous DMF and then treated with anhydrous TEA (60 μL) under nitrogen atmosphere. To this solution, mPEG-NHS (0.2 g, 0.04 mmol) in 3 mL anhydrous DMF was added. The reaction mixture was stirred at 35oC for 24 h under nitrogen atmosphere. The final clear organic solution was dialysis against ethanol (Molecular weight cut-off/MWCO: 1,000 Da) to remove the excess 4,4-Azodianiline. With the removal of ethanol, the orange powder mPEG-Azo-NH2 was obtained (yield: 65%) |