116467-74-4Relevant articles and documents
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 (1988)
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.
Regioselective Dihydroarene Oxide Formation during ortho-Hydroxylation of Halogenobenzenes by Fungi
Auret, Barbara J.,Balani, Suresh K.,Boyd, Derek R.,Greene, Ruth M. E.,Berchtold, Glenn A.
, p. 2659 - 2664 (1984)
ortho-Hydroxylation of chloro- and bromo-benzene occurred in the presence of growing cultures of the fungi Rhizopus arrhizus, Rhizopus stolonifer, and Cunninghamella elegans.The absence of a primary kinetic isotope effect and the presence of the NIH shift are consistent with dihydroarene oxides being initial metabolites.N.m.r. analysis of the deuterium-labelled o-halogenophenol products suggested that enzyme-catalysed epoxidation occurs preferentially at the 2,3-bond.
