Post-synthetic modification is a powerful technique allowing access to noncanonical peptide derivatives in a selective manner, but it has not so far been applied for the installation of multiple arrays of modified side chains. Here, we use this approach in solution phase to prepare short N- and C-capped homooligomers of 3-amino-1-methylazetidine-3-carboxylic acid with all the azetidine side chain functions in free amine form. The key step is the multiple reductive amination reaction of the corresponding post-synthetically deprotected secondary amines.

中文翻译：

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3-Amino-1-methylazetidine-3-carboxylic Acid 均聚物的合成后修饰策略

合成后修饰是一种强大的技术，允许以选择性方式获取非规范肽衍生物，但迄今为止尚未应用于安装多个修饰侧链阵列。在这里，我们在溶液相中使用这种方法来制备 3-amino-1-methylazetidine-3-carboxylic acid 的短 N 和 C 封端均聚物，所有氮杂环丁烷侧链功能均以游离胺形式存在。关键步骤是相应的合成后脱保护仲胺的多重还原胺化反应。