at 300 K as three-component (ringcis-open-ringtrans) tautomeric mixtures. The electronic effects of the 2-aryl substituents on the tautomeric equilibria were described by the Hammett equation. Good correlations were found between the equilibrium constants and the Hammett–Brown parameter (σ+) of the substituent X on the 2-phenyl group.
(S)-2-
氨基-2-苯基
乙醇或(S)-2-
氨基-3-苯基
丙醇与取代的
苯甲醛在
甲醇或
水中的缩合生成结晶产物,证明该产物在300 K的CDCl 3中以3 -组分(环顺式-开环反式)互变异构混合物。通过哈米特方程描述了2-芳基取代基对互变异构体平衡的电子效应。在平衡常数与2-苯基上的取代基X的Hammett-Brown参数(σ +)之间发现了良好的相关性。