α-生育酚模型—色满酚氧自由基的电子自旋共振研究

ELECTRON SPIN RESONANCE STUDIES OF α-TOCOPHEROL MODEL-CHROMANOXYI RADICAL

本文研究了一种新α-生育酚(维生素E)模型化合物——手性2,5,7,8—四甲基—2—乙氧基—6—羟基色满(ETC)的抗氧化性能.以甲苯为溶剂,以二叔丁基过氧化物为氧化剂,在紫外光的照射下记录色满酚氧自由基的ESR谱.并测得超精细偶合常数,用计算机描绘出色满酚氧自由基的模拟谱.在无氧条件下,ETC酚氧自由基信号缓慢地出现,随着时间的推移信号逐渐增强.在20分钟后呈极大值,然后信号逐渐减弱.在含氧条件下,ETC酚氧自由基信号速增速减,40分钟后趋于稳定.样品停止光照半小时之后,上述现象均可重复.据此,本文对ETC酚氧自由基的形成及反应性进行了讨论.

Electron spin resonance measurements were performed for the chromanoxyl radical obtained from a new α-Tocopherol model compound (chiral 2-ethoxy-2, 5, 7, 8-tetramethyl-6-chromanol) by oxidizing the phenol precursors with di-tert -butyl peroxide in toluene. The proton byperfine coupling constants and giso value were determined. The computer simulation spectrum was made by use of these hyperfine coupling constants.The intensity of the ESR signal of chromanoxyl radical was week under degassed condition, and increased to a maximum after 20 min., then decayed rapidly. The intensity of the chromanoxyl radical was strong when oxygen present and decayed rapidly as soon as it appeared. It approached a steady state after 40 min..The implication of these results has been discussed.