We present the synthesis development of amphiphilic, degradable poly(2-ethyl-2-oxazoline) (PEtOx) analogue block copolymers in a modular fashion utilizing the strain-promoted azide–alkyne cycloaddition (SPAAC). Subsequently to preliminary ω-end group oxidation studies by means of matrix-assisted laser desorption ionization mass spectrometry, a clickable, degradable poly(2-ethyl-2-oxazoline-stat-glycine) was synthesized via a three step post-polymerization synthesis procedure comprising the hydrolysis of azido-terminated PEtOx yielding the linear, azido-terminated poly(ethylene imine), the partial oxidation of the polymer backbone to incorporate randomly distributed glycine moieties and the re-introduction of the N-acyl ethylene imine repeating units. The azido ω-end group enabled the utilization in SPAAC. In a proof of concept approach, the degradable PEtOx analogue and its non-degradable relative were attached to a hydrophobic poly(2-n-nonyl-2-oxazoline) as well as a poly(ε-caprolactone) block via SPAAC. The successful conjugations were confirmed by in depth characterization utilizing NMR spectroscopy, size exclusion chromatography and matrix-assisted laser desorption ionization mass spectrometry. Due to its simplicity and flexibility the presented SPAAC approach offers numerous possibilities for the design of block copolymers comprising degradable poly(2-oxazoline) segments.

中文翻译：

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通过无铜点击化学包含可降解聚（2-乙基-2-恶唑啉）类似物的嵌段共聚物

我们利用应变促进的叠氮化物-炔环加成 (SPAAC) 以模块化方式展示了两亲性、可降解的聚 (2-乙基-2-恶唑啉) (PEtOx) 类似物嵌段共聚物的合成开发。随后通过基质辅助激光解吸电离质谱法，可点击，来初步ω端基氧化研究降解聚（2-乙基-2- oxazoline- STAT -甘氨酸）合成通过三步聚合后合成方法包括叠氮基封端的 PEtOx 的水解，产生线性、叠氮基封端的聚（乙烯亚胺），聚合物主链的部分氧化以掺入随机分布的甘氨酸部分，以及重新引入N-酰基乙烯亚胺重复单元。azido ω-end 基团可以在 SPAAC 中使用。在概念验证方法中，可降解的 PEtOx 类似物及其不可降解的类似物通过 SPAAC 连接到疏水性聚（2- n-壬基-2-恶唑啉）以及聚（ε-己内酯）嵌段上。通过使用 NMR 光谱、尺寸排阻色谱和基质辅助激光解吸电离质谱进行深入表征，证实了成功的结合。由于其简单性和灵活性，所提出的 SPAAC 方法为包含可降解聚（2-恶唑啉）链段的嵌段共聚物的设计提供了多种可能性。