N-Aminopyrroledione–hydrazonoketene–pyrazolium oxide–pyrazolone rearrangements and pyrazolone tautomerism
作者:Sieglinde Ebner、Bianca Wallfisch、John Andraos、Ilyas Aitbaev、Michael Kiselewsky、Paul V. Bernhardt、Gert Kollenz、Curt Wentrup
DOI:10.1039/b304070d
日期:——
Flash vacuum thermolysis (FVT) of 1-(dimethylamino)pyrrole-2,3-diones 5 causes extrusion of CO with formation of transient hydrazonoketenes 7. The transient ketenes 7 are observable in the form of weak bands at 2130 (7a) or 2115 cm-1 (7b) in the Ar matrix IR spectra resulting from either FVT or photolysis of either 5 or 1,1-dimethylpyrazolium-5-oxides 8, and these absorptions are in excellent agreement
1-(二甲基氨基)吡咯-2,3-二酮5的快速真空热解(FVT)导致CO的挤出并形成瞬态肼基酮7。在2130(7a)或2115处以弱带的形式观察到瞬态烯酮7 FVT或5或1,1-二甲基吡唑鎓5氧化物8的FVT或光解所产生的Ar矩阵IR光谱中的cm-1(7b),这些吸收与B3LYP / 6-31G *频率计算非常吻合。在FVT条件下,烯酮7环化成吡唑鎓氧化物8,其经历甲基的1,4-迁移,得到1,4-二甲基-3-苯基吡唑-5(4H)-1a和1,4,4-三甲基-3-苯基吡唑-5(4H)-1 9b。9a的所有三个互变异构体均已表征。CH形式9a(气相,固态和低极性溶剂中最稳定的形式),OH形式9a'