Eight derivatives of 1-(2-alkoxycarbonylphenyl)-3-phenyltriazene (R = methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, and allyl) have been synthesized and their UV-VIS, IR, 1H and 13C NMR spectra measured. The NMR spectra have been interpreted in detail. The kinetics of acid-catalyzed decomposition and base-catalyzed cyclization of the title compounds have been measured in 52.1% w/w methanol at 25.0 °C. The unit reaction order has been verified and the cyclization product has been identified. The pH-profiles obtained have been used to calculate the catalytic rate constants kA (acid-catalyzed decomposition) and kB (base-catalyzed cyclization) of all the derivatives; the constants have been interpreted with regard to inductive and steric effects. The catalytic rate constant kA has been found to be independent of the substituents. The catalytic rate constant kB depends statistically significantly upon both inductive and steric effects, the sensitivity to the former being more significant. The experimental results and their interpretation confirm the base-catalyzed cyclization mechanism with formation of tetrahedral intermediate as the rate-limiting step.
已合成了1-(2-烷氧羰基苯基)-3-苯基三氮烯的八种衍生物(R = 甲基、乙基、丙基、异丙基、丁基、异丁基、己基和烯丙基),并测量了它们的紫外-可见、红外、^1H和^13C核磁共振光谱。详细解释了核磁共振光谱。在25.0°C的52.1% w/w甲醇中测定了这些化合物的酸催化分解和碱催化环化的动力学。验证了单位反应阶数,并鉴定了环化产物。利用得到的pH-曲线计算了所有衍生物的酸催化分解催化速率常数kA和碱催化环化催化速率常数kB;这些常数已根据归纳和空间效应进行了解释。发现酸催化分解催化速率常数kA与取代基无关。碱催化环化催化速率常数kB在统计上显著取决于归纳和空间效应,对前者的敏感性更显著。实验结果及其解释证实了碱催化环化机制,形成四面体中间体作为速率限制步骤。