Oxidation‐responsive aliphatic polycarbonates represent a promising branch of functional biodegradable polymers. This paper reports the synthesis and ring‐opening polymerization (ROP) of an eight‐membered cyclic carbonate possessing phenylboronic pinacol ester (C3) and the H₂O₂‐triggered degradation of its polymer (PC3). C3 is prepared from the inexpensive and readily available diethanolamine with a moderate yield and undergoes the well‐controlled anionic ROP with a living character under catalysis of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene. It can also be copolymerized with l‐lactide, trimethylene carbonate, and 5‐ter‐butyloxycarbonylamino trimethylene carbonate, affording the copolymers with a varied distribution of the repeating units. To clearly demonstrate the oxidative degradation mechanism of PC3, this paper first investigates the H₂O₂‐induced decomposition of small‐molecule model compounds by proton nuclear magnetic resonance (¹H NMR). It is found that the adduct products formed by the in‐situ‐generated secondary amines and p‐quinone methide (QM) are thermodynamically unstable and can decompose slowly back to QM and the amines. On this basis, this paper further studies the H₂O₂‐accelerated degradation of PC3 nanoparticles that are prepared by the o/w emulsion method. A sequential process of oxidation of the phenylboronic ester, 1,6‐elimination of the in‐situ‐generated phenol, releasing CO₂ and intramolecular cyclization or isomerization is proposed as the degradation mechanism of PC3.

中文翻译：

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N取代的八元环状碳酸酯的氧化响应脂肪族聚碳酸酯：合成与降解研究

氧化反应性脂肪族聚碳酸酯代表着功能性可生物降解聚合物的一个有前途的分支。本文报道了具有苯硼酸频哪醇酯（C3）的八元环状碳酸酯的合成和开环聚合（ROP）及其聚合物（PC3）的H ₂ O ₂触发降解。C3由廉价且易于获得的二乙醇胺制备，产率适中，并在1,8-二氮杂双环[5.4.0] undec-7-ene催化下经历具有良好活性的阴离子型ROP。它也可以与l-丙交酯，碳酸三亚甲基酯和5- ter共聚-丁氧基羰基氨基碳酸三亚甲基酯，为共聚物提供不同分布的重复单元。为了清楚地说明PC3的氧化降解机理，本文首先研究了H ₂ O ₂诱导的质子核磁共振（¹ H NMR）分解的小分子模型化合物。发现由原位生成的仲胺和对苯二甲甲烷（QM）形成的加合物产物在热力学上不稳定，可以缓慢分解回QM和胺类。在此基础上，本文进一步研究为H ₂ Ø ₂的-accelerated降解PC3通过o / w乳液法制备的纳米颗粒。作为PC3的降解机理，提出了苯硼酸酯的氧化，原位生成的苯酚的1,6消除，释放CO ₂以及分子内环化或异构化的顺序过程。