热重排4-乙基-3,5-二苯基-4 H -1,2,4-三唑1到相应的1-乙基-3,5-二苯基-1-烷基-1 H -1的动力学在15-Crown-5和十八烷中于330°C研究了2,2,4-三唑2。在十八烷中,反应非常缓慢,但在15-Crown-5中反应良好。反应的反应顺序不是恒定的,而是随着反应的进行从初始的二阶速率定律变为一阶速率定律。浓度依赖性反应阶数n c大于时间依赖性速率定律n t证实了这一点。。观察的理由是,在高底物浓度下,反应顺序是二阶,而在低浓度下,竞争性溶剂辅助反应起着越来越重要的作用。数据与分子间亲核取代反应中的中性4-烷基-三唑形成三唑三唑盐的机理一致,三唑鎓三唑盐在随后的亲核反应中得到观察到的产物。
The mechanism for the thermalrearrangement of 4-alkyl-1,2,4-triazoles to the corresponding 1-alkyl-1,2,4-triazoles, was studied by cross-over experiments with mixtures of 4-ethyl-3,5-diphenyl-4H-1,2,4-triazole and 3,5-bis(4-methylphenyl)-4-propyl-4H-1,2,4-triazole. This gave support to a proposed mechanism involving the formation of an ionic triazolium triazolate intermediate, and a subsequent nucleophilic