116467-72-2Relevant academic research and scientific papers
Kinetic Studies by Means of the NMR Techniques. I. Acid-Catalyzed Proton-Exchange Reactions of Some Substituted Phenols
Yoshino, Akihiro,Nakashima, Yasuki,Takahashi, Kensuke
, p. 3393 - 3398 (1988)
A kinetic study was conducted on the acid-catalyzed proton-deuteron-exchange reactions of several substituted phenols.The rates of the exchange were determined by using the two-bond isotope shifts (2Δ) on the carbons and the pattern-fitting analyses for the 13C NMR signals.The observed reaction rates can be expressed additively with substituent parameters.The parameters of the para positions are linearly correlated to the ?p(1+) with ρ=-3.6.
Ortho-Selective Hydrogen Isotope Exchange of Phenols and Benzyl Alcohols by Mesoionic Carbene-Iridium Catalyst
Zhao, Liang-Liang,Wu, Yixin,Huang, Shiqing,Zhang, Zengyu,Liu, Wei,Yan, Xiaoyu
supporting information, p. 9297 - 9302 (2021/11/30)
Hydrogen isotope exchange reactions of phenols and benzyl alcohols have been achieved by a mesoionic carbene-iridium catalyst with high ortho selectivity and high functional group tolerance. Control experiments indicated that acetate is crucial to realize the ortho selectivity, whereas density functional theory calculations supported an outer-sphere direction with hydrogen bonding between acetate and the hydroxyl group.
Direct Hydroxylation of Benzene to Phenol Using Hydrogen Peroxide Catalyzed by Nickel Complexes Supported by Pyridylalkylamine Ligands
Morimoto, Yuma,Bunno, Shuji,Fujieda, Nobutaka,Sugimoto, Hideki,Itoh, Shinobu
supporting information, p. 5867 - 5870 (2015/05/27)
Selective hydroxylation of benzene to phenol has been achieved using H2O2 in the presence of a catalytic amount of the nickel complex [NiII(tepa)]2+ (2) (tepa = tris[2-(pyridin-2-yl)ethyl]amine) at 60°C. The maximum yield of phenol was 21% based on benzene without the formation of quinone or diphenol. In an endurance test of the catalyst, complex 2 showed a turnover number (TON) of 749, which is the highest value reported to date for molecular catalysts in benzene hydroxylation with H2O2. When toluene was employed as a substrate instead of benzene, cresol was obtained as the major product with 90% selectivity. When H218O2 was utilized as the oxidant, 18O-labeled phenol was predominantly obtained. The reaction rate for fully deuterated benzene was nearly identical to that of benzene (kinetic isotope effect = 1.0). On the basis of these results, the reaction mechanism is discussed.
Chemo- and regioselective direct hydroxylation of arenes with hydrogen peroxide catalyzed by a divanadium-substituted phosphotungstate
Kamata, Keigo,Yamaura, Taiyo,Mizuno, Noritaka
supporting information; experimental part, p. 7275 - 7278 (2012/08/28)
Peroxide in, phenol out: The catalyst [-PW10O38V 2(μ-OH)2]3- showed high activity in the hydroxylation of various aromatic compounds with aqueous H2O 2. The system was regioselective, producing para-phenols from monosubstituted benzene derivatives. Furthermore, alkylarenes with reactive side-chain Ca spa 3-H bonds could be chemoselectively hydroxylated without significant formation of side-chain oxygenated products. Copyright
Characteristic Effect of Pyridine on the NIH Shift and Selectivity in the Monooxygenation of Aromatic Compounds Catalyzed by a Nonheme Iron Complex/Hydroquinones/O2 System
Funabiki, Takuzo,Toyoda, Takehiro,Yoshida, Satohiro
, p. 1279 - 1282 (2007/10/02)
The high values of the NIH and Me-NIH shifts were observed in the hydroxylation of aromatic compounds such as toluene and xylenes with O2 by the catalytic system in the title.The pyridine concentration greatly affected not only the NIH shift, but the selectivity to form phenols by hydroxylation of the aromatic ring and to form aldehydes by oxidation of the methyl group.
Mechanism of Aromatic Hydroxylation in the Fenton and Related Reactions. One-Electron Oxidation and the NIH Shift
Kurata, Tsunehiko,Watanabe, Yasumasa,Katoh, Makoto,Sawaki, Yasuhiko
, p. 7472 - 7478 (2007/10/02)
Hydroxylation of substituted benzenes in the Fenton and peroxydisulfate oxidations has been studied mechanistically in relation to the NIH shift.One-electron oxidants such as Fe3+, Cu2+, and quinones increased the shift value effectively in aqueous or acetonitrile solutions.The shift values obtained were as high as 40 - 50 percent and dependent on both substituents (i. e., MeO Me, Cl, MeCO) and solvents.A high shift value was obtained also for the methoxylation, indicating unimportance of the arene oxide intermediate for the NIH shift.Oxygen reduced the shift effectively and sometimes was incorporated into product phenols with selective meta orientation.The means that oxygen abstracts a hydrogen atom from or adds to the oxycyclohexadienyl radical intermediate.It is concluded that the one-electron oxidation of the dienyl radical is the key step for the shift and its rates are dependent on substituents, oxidants, and solvents.
