作者:Ferenc Fülöp、László Lázár、Gábor Bernáth、Reijo Sillanpää、Kalevi Pihlaja
DOI:10.1016/s0040-4020(01)86311-0
日期:1993.3
The aryl substituents at positions 4 and 6 do not exert observable electronic effects on the ring-chain tautomeric ratios of 2,4- or 2,6-diarylsubstituted-tetrahydro-1,3-oxazines. On the other hand, the electronic effect of the 2-aryl substituent is marked: in all eight series studied, the equilibria can be described by the equation log K = ϱ σ+ +log K0, where ϱ+ is the Hammett-Brown constant of the
在4和6位上的芳基取代基对2,4-或2,6-二芳基取代的-四氢-1,3-恶嗪的环链互变异构比没有可观察到的电子效应。另一方面,2-芳基取代基的电子效应是明显的:在所有研究的八个系列中,平衡均可以用等式log K = ϱσ + + log K 0来描述,其中ϱ +是哈米特-布朗= 2-芳基取代基的常数,ϱ是环系统的恒定特征(= 0.75±0.05)。