Organocatalytic Ring-Opening Polymerization of N-Acylated-1,4-oxazepan-7-ones Toward Well-Defined Poly(ester amide)s: Biodegradable Alternatives to Poly(2-oxazoline)s,ACS Macro Letters

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Organocatalytic Ring-Opening Polymerization of N-Acylated-1,4-oxazepan-7-ones Toward Well-Defined Poly(ester amide)s: Biodegradable Alternatives to Poly(2-oxazoline)s
ACS Macro Letters ( IF 5.1 ) Pub Date : 2020-03-18 , DOI: 10.1021/acsmacrolett.0c00040
Xin Wang ₁ , Nikos Hadjichristidis ₁

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We report a series of poly(ester amide)s (PEAs) synthesized by organocatalytic ring-opening polymerization (ROP) of N-acylated-1,4-oxazepan-7-one (OxP) monomers, produced from N-acylated-4-piperidones using the Baeyer–Villiger oxidation reaction. The ROP of OxPs, conducted in CH₂Cl₂ at room temperature with benzyl alcohol as initiator and TBD/TU (1,5,7-triazabicyclo[4.4.0]dec-5-ene/thiourea) as a binary organocatalytic system, revealed a controlled/living character. The thermodynamics of the ROP highly depends on the N-acylated substituent of monomers, with the following reactivity order: OxP_Ph > OxP_Me > OxP_Pr > OxP_Bn. Based on NMR results, it seems that our system follows the hydrogen bonding bifunctional activation mechanism. All intermediates and final products were characterized by NMR, MALDI-TOF MS, SEC, and DSC techniques. All poly(N-acylated-1,4-oxazepan-7-one) (POxP) polymers are amorphous with different glass transition temperatures (T_g), depending on the N-acylated substituent (T_g: −2.90 to 43.75 °C). Among the synthesized polymers, only POxP_Me was water-soluble and it degraded much faster than polycaprolactone in an aqueous phosphate buffer saline solution (pH = 7.4). Therefore, poly(N-acylated-1,4-oxazepan-7-one)s are potential biodegradable alternatives to poly(2-oxazoline)s.

中文翻译：

N-Acylated-1,4-oxazepan-7-ones 的有机催化开环聚合制备明确的聚（酯酰胺）：聚（2-恶唑啉）的可生物降解替代品

我们报告了一系列由N -acylated-1,4-oxazepan-7-one (OxP) 单体的有机催化开环聚合 (ROP) 合成的聚 (酯酰胺) (PEA )，由N -acylated-4生产-哌啶酮使用 Baeyer-Villiger 氧化反应。OxPs 的 ROP，在室温下在 CH ₂ Cl ₂中进行，苯甲醇作为引发剂，TBD/TU (1,5,7-triazabicyclo[4.4.0]dec-5-ene/thiourea) 作为二元有机催化体系，揭示了一个受控/活生生的角色。ROP的热力学高度取决于单体的N-酰化取代基，具有以下反应顺序：OxP _Ph > OxP _Me > OxP _Pr > OxP _Bn. 基于核磁共振结果，我们的系统似乎遵循氢键双功能活化机制。所有中间体和最终产品均通过 NMR、MALDI-TOF MS、SEC 和 DSC 技术进行了表征。所有聚（N-酰化-1,4-oxazepan-7-one）（POxP）聚合物都是无定形的，具有不同的玻璃化转变温度（Tg），取决于N-酰化取代_基（_{Tg ：}-2.90至 43.75 °C ））。在合成的聚合物中，只有 POxP _Me是水溶性的，它在磷酸盐缓冲盐水溶液（pH = 7.4）中的降解速度比聚己内酯快得多。因此，聚（N-acylated-1,4-oxazepan-7-one)s 是聚 (2-oxazoline)s 的潜在可生物降解替代品。

更新日期：2020-04-23

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