Isomerisations akin to the Dimroth rearrangement. Part II. The equilibria of 4-mercapto-1,2,3,5,7-penta-azaindenes with 4-amino-1-thia-2,3,5,7-tetra-azaindenes
作者:D. J. Brown、M. N. Paddon-Row
DOI:10.1039/j39670001856
日期:——
When 1-benzyl-4-mercapto-1,2,3,5,7-penta-azaindene or 4-benzylamino-1-thia-2,3,5,7-tetra-azaindene is boiled in an alcohol or maintained in the molten state, the equilibrium mixture consists largely of the thia-isomer. Analogues in which the benzyl group is replaced by a phenyl or p-substituted phenyl group behave similarly. For each pair of isomers, the first-order rate constant for equilibration
当将1-苄基-4-巯基-1,2,3,5,7-五氮杂茚满或4-苄基氨基-1-硫杂-2,3,5,7-四氮杂茚满煮沸或保持在在熔融状态下,平衡混合物主要由硫杂异构体组成。其中苄基被苯基或对位取代的苯基取代的类似物表现相似。对于每对异构体,记录在丁醇-甲氧基乙醇中平衡的一级速率常数和平衡常数。速率常数对p的哈米特sigma值的对数对数图-取代基是直线的。平衡常数也随取代基和温度而变化:电子抽出和更高的温度更有利于噻吩异构体。在二甲亚砜溶液中,平衡处于中途;在氢氧化钠水溶液中,五氮杂茚满(阴离子)是有利的。每种化合物都是通过直接途径以及通过异构化制备的。