Proximity effects in diaryl derivatives. Part 7. Mechanism of base-catalysed rearrangement of 2-(hydroxyamino)aryl phenyl sulphones to 2-hydroxy-2′-(phenylsulphonyl)azoxybenzenes
作者:Robert J. Cummings、Michael F. Grundon、Anthony C. Knipe、Adil S. Wasfi
DOI:10.1039/p29830000105
日期:——
Base-catalysed rearrangement of a 2-(hydroxyamino)aryl phenyl sulphone (1b) to the 2-hydroxy-2′-(phenylsulphonyl)azoxybenzene (4b) was shown by isolation and kinetic studies to be a rapid reaction requiring oxygen; in the absence of oxygen the sulphur-free azoxybenzene (3; R = Cl) was the only product isolated from the reaction of (1c). A mechanism for the formation of 2-hydroxyazoxybenzenes (4) is
分离和动力学研究表明,碱催化的2-(羟基氨基)芳基苯基砜(1b)重排至2-羟基-2'-(苯基磺酰基)氮杂苯(4b)是需要氧气的快速反应。在没有氧气的情况下,无硫的z氧基苯(3; R = Cl)是唯一从(1c)反应中分离的产物。提出了形成2-羟基乙氧基苯(4)的机理(方案2),涉及亚硝基芳基自由基阴离子(9)二聚为NN的二价阴离子。-二醇(10),以及通过氧从氮原子的分子内转移来取代苯磺酰基。对2-(羟氨基)芳基苯硫醚(12)在氧气存在下的碱催化反应的类似研究表明,离去基团较弱时,会形成双(苯硫基)氮氧基苯(11; R = SPh)。描述了一种由硝基苯制备N-芳基羟胺的改进方法。