γ-chromanoxyl radical | 23183-54-2

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: γ-chromanoxyl radical
• 英文别名: γ-tocopheroxyl
• CAS: 23183-54-2；83376-96-9
• 化学式: C₂₈H₄₇O₂
• 分子量: 415.68
• InChiKey: LBDXFUVWQHFODO-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  8.97
• 重原子数：
  30.0
• 可旋转键数：
  12.0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.79
• 拓扑面积：
  29.13
• 氢给体数：
  0.0
• 氢受体数：
  1.0

反应信息

• 作为产物：
  描述：

  3,4-二氢-2,7,8-三甲基-2-(4,8,12-三甲基十三烷)-2H-1-苯并吡喃-6-醇 在 2,6-di-tert-butyl-4-(4-methoxyphenyl)phenoxyl 作用下， 以 乙醇 为溶剂， 生成 γ-chromanoxyl radical
  参考文献：
  名称：

  Stopped-Flow Investigation of Antioxidant Activity of Tocopherols

  摘要：

  通过 ESR 测量观察到，α-、β-、γ- 和 δ-生育酚（维生素 E）在苯中与稳定的苯氧自由基发生氧化反应，立即产生相应的生育酚氧自由基。作为生育酚与生物系统中不稳定自由基（ROO-、RO- 和 HO-）反应的模型，使用停流技术分光光度法测定了 α-、β-、γ- 和 δ-生育酚与乙醇溶液中稳定苯氧自由基的反应速率。在 25.0 °C 的乙醇中，得到的二阶速率常数分别为 (5.12±0.36)×103 (α-Toc), (2.24±0.04)×103 (β-Toc), (2.42±0.16)×103 (γ-Toc), 和 (0.51±0.01)×103 (δ-Toc), M-1 s-1。这些相对速率与通过消耗 O2 和 ESR 法研究生育酚对聚（苯乙烯基过氧乙酸）和乙烯基过氧乙酸自由基的反应活性所获得的速率非常吻合。结果表明，生育酚的相对反应活性（即相对抗氧化活性）并不取决于发生反应的不稳定自由基的种类。

  DOI：

  10.1246/bcsj.59.3113

文献信息

• Formation and Decay Dynamics of Vitamin E Radical in the Antioxidant Reaction of Vitamin E
  作者：Kazuo Mukai、Aya Ouchi、Akiko Mitarai、Keishi Ohara、Chihiro Matsuoka

  DOI：10.1246/bcsj.82.494

  日期：2009.3.15

  understand the dynamics of antioxidant actions of vitamin E (α-, β-, γ-, and δ-tocopherols, TocH) in biological systems, kinetic study of the formation and decay reactions of vitamin E radicals (α-, β-, γ-, and δ-tocopheroxyls, Toc•) has been performed in organic solvents, using stopped-flow spectrophotometry. By mixing α-, β-, γ-, and δ-TocH with aryloxyl radical (ArO•) in ethanol, the peaks of the UV-vis

  为了了解维生素 E（α-、β-、γ-和 δ-生育酚，TocH）在生物系统中的抗氧化作用动力学，对维生素 E 自由基（α-、β -、γ- 和 δ-生育酚 (Toc•) 已在有机溶剂中使用停流分光光度法进行了分析。通过将 α-、β-、γ- 和 δ-TocH 与芳氧基 (ArO•) 在乙醇中混合，α-、β-、γ- 和 δ-Toc• 自由基引起的 UV-vis 吸收峰迅速出现在ca。430-340 nm，出现最大值，然后逐渐衰减。α-Toc• 的形成和衰变（即双分子歧化）反应的二级速率常数（kf 和 2k d ）是通过将观测曲线与通过相关微分方程数值计算获得的模拟曲线进行比较来确定的。对上述反应。根据结果​​，确定了α-Toc•自由基的光谱的最大吸收波长(λ max i) 和摩尔消光系数(ei ) (i = 1-4)。已经观察到显着的溶剂效应对于 α-Toc• 自由基的反应速率（kf 和 2k d
• Stopped-Flow Investigation of Antioxidant Activity of Tocopherols
  作者：Kazuo Mukai、Yoshiko Watanabe、Yuichi Uemoto、Kazuhiko Ishizu

  DOI：10.1246/bcsj.59.3113

  日期：1986.10

  It was observed by ESR measurement that the oxidation of α-, β-, γ-, and δ-tocopherols (vitamin E) with a stable phenoxyl radical in benzene immediately gives corresponding tocopheroxyl radicals. The rates of reaction of α-, β-, γ-, and δ-tocopherols with the stable phenoxyl radical in ethanol solution have been determined spectrophotometrically using stopped-flow technique, as a model reaction of tocopherols with unstable free radicals (ROO·, RO·, and HO·) in biological systems. The second-order rate constants obtained are (5.12±0.36)×103 (α-Toc), (2.24±0.04)×103 (β-Toc), (2.42±0.16)×103 (γ-Toc), and (0.51±0.01)×103 (δ-Toc), M−1 s−1 in ethanol at 25.0 °C. The relative rates agree well with those obtained from studies of the reactivities of tocopherols toward poly(styrylperoxyl) and galvinoxyl radicals by O2 consumption and by ESR method, respectively. The results suggest that the relative reactivities, that is, relative antioxidant activities of tocopherols do not depend on the kinds of unstable free radicals reacted.

  通过 ESR 测量观察到，α-、β-、γ- 和 δ-生育酚（维生素 E）在苯中与稳定的苯氧自由基发生氧化反应，立即产生相应的生育酚氧自由基。作为生育酚与生物系统中不稳定自由基（ROO-、RO- 和 HO-）反应的模型，使用停流技术分光光度法测定了 α-、β-、γ- 和 δ-生育酚与乙醇溶液中稳定苯氧自由基的反应速率。在 25.0 °C 的乙醇中，得到的二阶速率常数分别为 (5.12±0.36)×103 (α-Toc), (2.24±0.04)×103 (β-Toc), (2.42±0.16)×103 (γ-Toc), 和 (0.51±0.01)×103 (δ-Toc), M-1 s-1。这些相对速率与通过消耗 O2 和 ESR 法研究生育酚对聚（苯乙烯基过氧乙酸）和乙烯基过氧乙酸自由基的反应活性所获得的速率非常吻合。结果表明，生育酚的相对反应活性（即相对抗氧化活性）并不取决于发生反应的不稳定自由基的种类。
• Synthesis and kinetic study of antioxidant activity of new tocopherol (vitamin E) compounds
  作者：Kazuo Mukai、Yukio Kageyama、Tamie Ishida、Kazuyuki Fukuda

  DOI：10.1021/jo00264a010

  日期：1989.2
• Mechanism of antioxidant reaction of vitamin E: charge transfer and tunneling effect in proton-transfer reaction
  作者：Shinichi Nagaoka、Aya Kuranaka、Hideki Tsuboi、Umpei Nagashima、Kazuo Mukai

  DOI：10.1021/j100185a065

  日期：1992.3

  In order to shed light on the mechanism of proton-transfer reactions, a kinetic and ab initio study of the antioxidant action (intermolecular proton transfer) of vitamin E derivatives has been carried out. The second-order rate constants (k(s)'s) for the reaction of tocopherols (TocH's) with variously substituted phenoxyl radicals (PhO.'s) in ethanol were measured with a stopped-flow spectrophotometer. The half-wave reduction potentials (E1/2's) of PhO.'s were obtained by using a cyclic voltammetry technique. The result indicates that k(s) increases as the total electron-donating capacity of the alkyl substituents at the aromatic ring of TocH or the electron-withdrawing capacity of the substituent of PhO. increases. k(s) for the reaction of deuterated tocopherol derivatives (TocD's) with a PhO. in deuterated ethanol (C2H5OD, ethanol-d1) was also measured. A substantial deuterium kinetic isotope effect on k(s) is observed. In the reactions of each PhO. with various TocH's, a plot of log k(s) vs peak oxidation potential (E(p)) of TocH is found to be linear. The slope of its plot for TocD's is clsoe to that for TocH's. In the reactions of each TocH with various PhO.'s, a plot of log k(s) vs E1/2 of PhO. is found to be linear. The geometries of TocH's were optimized with the semiempirical modified neglect of diatomic overlap (MNDO) method. The Koopmans' theorem first ionization energies (IP) for those geometries were calculated with the ab initio method. In the reactions of a PhO. with various TocH's, plots of log k(s) vs IP, the activation energy (E(act)) vs IP, and E(p) vs IP are also found to be linear. From these results, it is considered that both the charge transfer and the proton tunneling play important roles in the antioxidant reaction of TocH. The transition state has the property of the charge-transfer species. The proton tunneling takes place below the transition state. Tunneling allows the proton to cut a corner on the potential energy surface. Our explanation will be widely applicable to many proton-transfer reactions.
• Autoxidation of biological molecules. 1. Antioxidant activity of vitamin E and related chain-breaking phenolic antioxidants in vitro
  作者：G. W. Burton、K. U. Ingold

  DOI：10.1021/ja00411a035

  日期：1981.10