Calixhydroquinones: a novel access to conformationally restricted, meta-substituted calixarenes †
作者:Mark Mascal、Ralf Warmuth、Russell T. Naven、Ross A. Edwards、Michael B. Hursthouse、David E. Hibbs
DOI:10.1039/a906442g
日期:——
described. These macrocycles are activated towards meta substitution, and reaction with bromine gives the first examples of persubstituted, phenol-derived calixarenes. The effect of meta substitution on calixarene mobility is demonstrated by the fixation of an otherwise mobile calix[4] system in the partial cone conformer, and the slowing of the ring inversion rate in calix[8]arenes.
Calix[4]quinone (7) and calix[4]hydroquinone (6) have been synthesis using three different synthetic pathways. The first pathway to 7 from calix[4]arene (1) consists of six steps: acetylation, Fries rearrangement, Baeyer-Villiger oxidation after acetylation, hydrolysis, and oxidation. The second pathway to 7 from 1 consists of four steps: acetylation, Fries rearrangement, reaction of the product obtained by Fries rearrangement with sodium azide, and oxidation. The third pathway to 7 from 1 is most convenient and consists of three steps: diazo coupling reaction, reduction, and oxidation. The NMR behavior of 6 and 7 is described.
Mechanistic Study on Electrochemical Reduction of Calix[4]quinone in Acetonitrile Containing Water
作者:Young-Ok Kim、Young Mee Jung、Seung Bin Kim、Byung Hee Hong、Kwang S. Kim、Su-Moon Park
DOI:10.1021/jp049864n
日期:2004.4.1
perchloric acid. CQ undergoes a series of reversible one electron reductions in dry CH3CN leading to anion radicals of each of p-benzoquinone units followed by formation of dianions. However, a series of following chemical-electrochemical reactions with protons takes place after the initial electron transfer in CH3CN containing water. The final product of this series of reactions is identified as CQH8 via
Tetrakis(methylimidazole) and tetrakis(methylimidazolium) calix[4]arenes: competitive anion binding and deprotonation
作者:Emma K. Bullough、Colin A. Kilner、Marc A. Little、Charlotte E. Willans
DOI:10.1039/c2ob07025a
日期:——
temperature, a feature that has been observed both in solution and in the solid-state. The cationic imidazolium exhibits a range of hydrogen bond interactions with anions, with the titration curves upon binding to basic anions suggesting sequential binding to both the upper and lower rims.