1,3-Dipolar Cycloaddition Reaction of Thiophenecarbonitrile<i>N</i>-Oxides with Various Dipolarophiles
作者:Yoshio Iwakura、Keikichi Uno、Shinsaku Shiraishi、Tatsuhiko Hongu
DOI:10.1246/bcsj.41.2954
日期:1968.12
synthesized by the chlorination of corresponding aldoxime with nitrosyl chloride. These compounds gave Δ2-isoxazolines and isoxazoles through 1,3-dipolar cycloaddition reaction with compounds having double or triple bond as dipolarophiles. In the cycloaddition reaction, II was less reactive than I. This would be explained by stability of II owing to electron-withdrawing ability of chlorine atom at 5-position
Thiophenc-2-carbonitrile N-oxide (I) 和 5-chlorothiophene-2-carbonitrile N-oxide (II) 是通过相应的醛肟与亚硝酰氯的氯化反应合成的。这些化合物与具有双键或三键的化合物作为亲偶极体通过 1,3-偶极环加成反应得到 Δ2-异恶唑啉和异恶唑。在环加成反应中,II 的反应性低于 I。这可以通过 II 的稳定性来解释,这是由于噻吩环 5 位的氯原子具有吸电子能力。Furoxans,腈N-氧化物的二聚体,由这些1,3-偶极子在不存在偶极体的情况下形成。