Gas-phase thermolysis of benzotriazole derivatives. Part 2: Synthesis of benzimidazo[1,2-b]cinnolines, a novel heterocyclic ring system, by pyrolysis of benzotriazole derivatives. Kinetic and mechanistic study
作者:Hicham H. Dib、Nouria A. Al-Awadi、Yehia A. Ibrahim、Osman M.E. El-Dusouqui
DOI:10.1016/j.tet.2003.09.009
日期:2003.11
Gas-phase pyrolysis of benzotriazolyl ketones and their arylhydrazones gave indole, benzimidazole and benzimidazo[1,2-b]cinnoline derivatives via interesting novel routes. The homogeneous first-order gas-phase pyrolysis of 10 arylhydrazono derivatives of α-benzotriazol-1-yl ketones was investigated over the temperature range 420–530 K. Five of these substrates were 2-(arylhydrazono)-2-(benzotriazo
苯并三唑基酮及其芳基hydr的气相热解通过有趣的新途径制得了吲哚,苯并咪唑和苯并咪唑[1,2- b ] cinnoline衍生物。在420–530 K的温度范围内研究了10种α-苯并三唑-1-基酮的芳基肼基衍生物的均相一阶气相热解。其中五种底物为2-(芳基肼基)-2-(苯并三唑-1) -基)-1-苯基乙酮衍生物(系列1),其余五种为相应的丙酮类似物(系列2)。系列1和2的化合物热解的Arrhenius频率因子(log A / s -1)的值分别为12.27±1.44和9.07±1.20,而Arrhenius活化能的值(E a/ kJ mol -1)分别为132.8±8.4和123.2±23.0。此外,还提供了反应途径以合理化动力学结果并考虑所研究底物的热解产物,即:(i)挤出N 2和形成导致取代的咪唑的1,3-双自由基反应性中间体(系列1); (ii)分子内亲核加成,环化和随后的断裂,无论是否损失H