Naphthalene Diols: A New Class of Antioxidants Intramolecular Hydrogen Bonding in Catechols, Naphthalene Diols, and Their Aryloxyl Radicals
作者:Mario C. Foti、Erin R. Johnson、Melinda R. Vinqvist、James S. Wright、L. Ross C. Barclay、K. U. Ingold
DOI:10.1021/jo020184v
日期:2002.7.1
intramolecular H-bonding stabilizes the radicals formed on H-atom transfer more than it does the parent diols, and this effect contributes to the increased HAT activity of 5 and 6 compared to the activities of the catechols. For example, the increased stabilization due to the intramolecular H-bond of 5 radical over 5 parent of 8.6 kcal/mol was about double that of 2 radical over 2 parent of 4.6 kcal/mol. Linear
根据H原子转移至2,2-di()的速率常数,发现1,8-萘二醇5及其4-甲氧基衍生物6是有效的H原子转移(HAT)化合物。 4-叔辛基苯基)-1-吡啶并肼基(DOPPH *),k(ArOH / DOPPH)*或在AIBN引发的苯乙烯自氧化抑制反应中的抗氧化剂k(ArOH / ROO)*。速率常数表明,5和6具有比邻二醇,邻苯二酚,1、2,3-萘二醇,2和3,5-二叔丁基邻苯二酚3更高的活性HAT化合物。化合物6具有几乎两倍于邻二醇的活性。维生素E模型化合物2,2,5,7,8-五甲基的抗氧化剂活性k(ArOH / ROO)* = 6.0 x 10(6)M(-)(1)s(-1) -6-chromanol,4。与酚(deltaBDEs)相比,OH键解离焓为1-6时,可预测HAT的反应级为2 <1 <3约4 < 5 <6与动力学结果基本一致。对二醇的计算表明,与母体二醇相比,分子内H键对H原子转移