Azidation of polyesters having pendent functionalities by using NaN 3 or DPPA-DBU and photo-crosslinking of the azidopolyesters

Dehydration polycondensation of bromoadipic acid and methylsuccinic acid with 1,4-butanediol was performed at 80 °C to synthesize aliphatic polyesters containing pendent bromo groups without dehydrobromination using scandium trifluoromethanesulfonate as the catalyst. Azidation of poly(butylene bromoadipate-co-butylene methylsuccinate) also proceeded to generate poly(butylene azidoadipate-co-butylene methylsuccinate) (Mn=10.4 × 103). We successively photo-crosslinked the resultant azidopolyesters by UV irradiation. We also described azidation of polyesters having pendent hydroxyl groups by using the ‘diphenylphosphoryl azide-1,8-diazabicyclo[5.4.0]undec-7-ene substitution strategy’ to produce water-soluble polyesters containing pendent azido groups (Mn=7.5 × 103).