The many postpolymerization modification opportunities of biocompatible poly(2-alkyl/aryl-2-oxazoline)s (PAOx), such as thiol–ene/thiol–yne, azide–alkyne cycloadditions, amidation, and transesterification, are one of the most appealing features of this polymer class for its popularity in biomedicine. Inspired by recent reports on guanidine-catalyzed transesterification and amidation reactions of methyl ester substrates, we explored the use of guanidines as a reactant for the modification of methyl ester functional PAOx, to obtain the respective acyl guanidines. The obtained acyl guanidines functional polymers display reactivity toward α-haloketones, yielding imidazole functional PAOx. The obtained polymer structures are protonated in a broad pH range, and the acyl guanidine moiety is demonstrated to be a cleavable linker under basic conditions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2616–2624

中文翻译：

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酰基胍官能团聚（2-恶唑啉）作为反应中间体和刺激响应材料

生物相容性聚 (2-烷基/芳基-2-恶唑啉) (PAOx) 的许多聚合后改性机会，例如硫醇-烯/硫醇-炔、叠氮化物-炔烃环加成、酰胺化和酯交换，是最吸引人的方法之一这种聚合物类的特点是它在生物医学中的普及。受最近关于甲基酯底物的胍催化酯交换和酰胺化反应的报道的启发，我们探索了使用胍作为反应物来修饰甲基酯官能 PAOx，以获得相应的酰基胍。获得的酰基胍官能聚合物对 α-卤代酮具有反应性，产生咪唑官能 PAOx。所得聚合物结构在较宽的 pH 值范围内被质子化，酰基胍部分在碱性条件下被证明是可裂解的接头。© 2019 Wiley Periodicals, Inc. J. Polym。科学，A 部分：Polym。化学。2019 , 57 , 2616–2624