Unexpected valence bond isomerization of [1,2,4]triazolo[3,4-c][1,2,4]benzotriazines under flash vacuum pyrolytic (fvp) conditions
作者:Walter J. Peláez、Gloria I. Yranzo、Csilla Gróf、Zsuzsanna Riedl、György Hajós
DOI:10.1016/j.tet.2005.05.047
日期:2005.8
to 525 °C was the unexpected valence bond isomerization of the angularly fused starting compounds to the isomeric linearly fused [1,2,4]triazolo[4,3-b][1,2,4]benzotriazine derivatives (9a–d), whereas at higher temperatures fragmentation products such as aromatic nitriles were also formed. Kinetic measurements revealed negative entropies of activation in the isomerization process, which suggest a concerted
在450至600°C之间研究了某些取代的[1,2,4]三唑[3,4- c ] [1,2,4]苯并三嗪衍生物(1a – d)的快速真空热解(fvp)。在高达525°C的温度下观察到的唯一转变是有角度融合的起始化合物的意外价键异构化为线性异构的[1,2,4] triazolo [4,3- b ] [1,2,4]苯并三嗪衍生物异构体(9a – d),而在较高的温度下也会形成碎片,例如芳族腈。动力学测量揭示了异构化过程中活化的负熵,这表明对中间抗芳族二嗪有协同的闭环反应。FVP实验也证明了标题异构化反应的可逆性。