Bromination of Non-α-Tocopherols: A Comparative Synthetic, Kinetic and Computational Study
作者:Anjan Patel、Stefan Böhmdorfer、Andreas Hofinger、Thomas Netscher、Thomas Rosenau
DOI:10.1002/ejoc.200900495
日期:2009.10
the 5a-bromo derivative by an oxidation/addition mechanism via the corresponding o-quinone methide becomes a competitive process. By measurement of product ratios at different temperatures, the relative and absolute activation energies of the reaction systems with parallel reactions going on (β- and δ-tocopherol) were established. The kinetic data were in very good agreement with DFT results that showed
广泛研究了三种非 α-生育酚及其截短的模型化合物在非极性溶剂中的溴化化学,并与 α-同类物的溴化化学进行了比较。溴化发生在所有非α-生育酚的游离芳香位置。在 δ-生育酚的情况下,C-5 优先于 C-7。在 5-甲基取代基的存在下,如在 β-生育酚中,通过氧化/加成机制通过相应的邻醌甲基化物形成 5a-溴衍生物成为一个竞争过程。通过测量不同温度下的产物比率,建立了平行反应(β-和δ-生育酚)的反应体系的相对活化能和绝对活化能。动力学数据与 DFT 结果非常吻合,DFT 结果表明 δ-生育酚溴化的产物比率与阳离子溴化中间体的稳定性相关。所有产品都经过全面表征,提供可靠的分析标准和参考化合物。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)