Nucleophilic substitution at sulphonyl sulphur. Part 1. Reactivity of thiophen-2-sulphonyl halides in water and methanol–acetonitrile
作者:Antonino Arcoria、Francesco P. Ballistreri、Giuseppe Musumarra、Gaetano A. Tomaselli
DOI:10.1039/p29810000221
日期:——
OH– an approximately linear Hammett correlation is found. Common chloride ion effects on the hydrolysis rate constants appear to be absent. Nucleophilic substitution reactions of substituted thiophen-2-sulphonyl chlorides were also studied in MeOH–MeCN, where the Hammett equation is obeyed. The data appear consistent with an SN2-type mechanism which can shift toward an SN1 or an SAN process depending
的反应动力学取代噻吩-2-磺酰氯化物和氟化物(5- OME,5-ME,H,5-CL,4-NO 2,5-NO 2与阴离子和中性亲核试剂),在25进行了研究在水° C。对于氯化物与H 2 O,AcO –和N 3 –的反应,以及对于氟化物的水解,观察到U型哈米特曲线。用于磺酰氯与苯胺,吡啶,咪唑和OH的反应–发现近似线性的哈米特相关性。似乎没有常见的氯离子对水解速率常数的影响。在MeOH–MeCN中也研究了取代的噻吩-2-磺酰氯的亲核取代反应,遵守了Hammett方程。该数据显示与一致的小号Ñ 2型机构,其可以朝向移位小号ñ 1或小号甲取决于亲核试剂Ñ过程中,对环取代基,并且在离去基团的能力。将More O'Ferrall和Thornton方法用于预测取代基对过渡态结构的影响似乎支持上述解释。