The present invention relates to derivatives of the 1H-pyrano[4,3-b]benzofuran-1-one structure and their nitrogen analogues which possess powerful antioxidant properties combined with a highly effective UV absorbing functionality in one molecule. These compounds are especially useful in cosmetical and dermatological formulations.
reaction with 4-hydroxy-pyrone/-benzopyrone afforded substituted benzofuran regioisomers whose structures with only two aromatic protons in total prevent a rapid structuralassignment. Based on the evaluation of 1H–13C long-range couplingconstants a rule of thumb could be deduced for an easy and unambiguous differentiation between the possible regioisomers formed. DFT frontier orbital calculations of the
漆酶催化的取代邻苯二酚的氧化,然后与 4-羟基吡喃酮对苯并吡喃酮取代 苯并呋喃区域异构体的结构总共只有两个芳香族质子,阻止了快速的结构分配。根据对1 H – 13 C远程耦合常数的评估,可以推断出经验法则,可以轻松而明确地区分可能形成的区域异构体。反应物的DFT前沿轨道计算提供了一个有趣的工具来解释关键反应的区域选择性。
Electrochemical oxidation of catechols in the presence of 4-hydroxy-6-methyl-2-pyrone
作者:Davood Nematollahi、Zinat Forooghi
DOI:10.1016/s0040-4020(02)00422-2
日期:2002.6
Electrochemicaloxidation of catechols (1a–1c) has been studied in the presence of 4-hydroxy-6-methyl-2-pyrone (3) as nucleophile in aqueous solution, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a–1c) participate in Michael addition reactions with 3 to form the corresponding heterocyclic compounds (6a–6c). In this work