Solid-Phase Synthesis of Amino Acid Derived N-Unsubstituted Pyrazoles via Sydnones
Solid-Phase Synthesis of Amino Acid Derived N-Unsubstituted Pyrazoles via Sydnones
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DOI：
10.1021/ol900704b
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发表时间：
2009-05-21
期刊：
影响因子：
5.2
通讯作者：
Yli-Kauhaluoma, Jari
中科院分区：
文献类型：
--
作者：
Harju, Kirsi;Vesterinen, Johanna;Yli-Kauhaluoma, Jari
介绍了一种在固体载体上合成N-未取代吡唑的新方法。固体载体作为氨基酸的保护基。N-保护的氨基酸是N-亚硝化的，随后在微波反应器中用乙酸酐处理得到中间离子合成酮，这些中间离子合成酮在1，3-偶极环加成反应中与炔发生原位反应。产物的无痕迹裂解使N-未取代吡唑的总收率很高。
A new method to synthesize N-unsubstituted pyrazoles on a solid support is described. The solid support acts as a protecting group for the amino acid. N-Protected amino acid is N-nitrosated, and the subsequent treatment with acetic anhydride in a microwave reactor yields mesoionic sydnones that react in situ in 1,3-dipolar cycloaddition reactions with alkynes. Traceless cleavage of the products gives N-unsubstituted pyrazoles in high overall yields.