In this paper, a simple and efficient synthetic route for the preparation of new heterocyclic amino acid derivatives containing azetidine and oxetane rings was described. The starting (N-Boc-azetidin-3-ylidene)acetate was obtained from (N-Boc)azetidin-3-one by the DBU-catalysed Horner-Wadsworth-Emmons reaction, followed by aza-Michael addition with NH-heterocycles to yield the target functionalised 3-substituted 3-(acetoxymethyl)azetidines. Methyl 2-(oxetan-3-ylidene)acetate was obtained in a similar manner, which was further treated with various (N-Boc-cycloaminyl)amines to yield the target 3-substituted 3-(acetoxymethyl)oxetane compounds. The synthesis and diversification of novel heterocyclic amino acid derivatives were achieved through the Suzuki-Miyaura cross-coupling from the corresponding brominated pyrazole-azetidine hybrid with boronic acids. The structures of the novel heterocyclic compounds were confirmed via 1H-, 13C-, 15N-, and 19F-NMR spectroscopy, as well as HRMS investigations.

中文翻译：

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通过NH-杂环与2-(氮杂环丁烷-或氧杂环丁烷-3-亚叉基)乙酸甲酯的Aza-Michael加成合成新的氮杂环丁烷和氧杂环丁烷氨基酸衍生物。


本文描述了一种简单、高效的合成路线，用于制备含有氮杂环丁烷和氧杂环丁烷环的新型杂环氨基酸衍生物。通过 DBU 催化的 Horner-Wadsworth-Emmons 反应，从 (N-Boc)azetidin-3-one 获得起始 (N-Boc-azetidin-3-ylidene) 乙酸酯，然后与 NH-杂环进行 aza-Michael 加成产生目标功能化的 3-取代 3-(乙酰氧基甲基)氮杂环丁烷。以类似的方式获得2-(氧杂环丁烷-3-亚基)乙酸甲酯，将其进一步用各种(N-Boc-环氨基)胺处理，得到目标3-取代的3-(乙酰氧基甲基)氧杂环丁烷化合物。通过相应的溴化吡唑-氮杂环丁烷杂化物与硼酸的铃木-宫浦交叉偶联，实现了新型杂环氨基酸衍生物的合成和多样化。新型杂环化合物的结构通过 1H-、 13C-、 15N- 和 19F-NMR 光谱以及 HRMS 研究得到证实。