1079-21-6Relevant articles and documents
Synthesis of hydroxybiphenyls
Kuznetsova,Postnova,Koshel',Lebedeva,Yun'kova,Koshel'
, p. 1288 - 1290 (2004)
Cyclohexylphenols were converted into hydroxybiphenyls via dehydration over large-scale palladium catalysts. The process involves slow reaction of the substrate with active centers of the catalyst with subsequent fast product formation and hydrogen desorption.
Metabolic activation of o-phenylphenol to a major cytotoxic metabolite, phenylhydroquinone: Role of human CYP1A2 and rat CYP2C11/CYP2E1
Ohno,Ozawa,Ohta,Miyajima,Kurebayashi,Sunouchi,Shimizy,Murayama,Matsumoto,Fukuoka
, p. 1005 - 1017 (2000)
1. The in vitro metabolic activation of o-phenylphenol has been evaluated as yielding a toxic metabolite, 2,5-dihydroxybiphenyl (phenylhydroquinone), by p-hydroxylation in liver microsomes of rat and human. The involvement of rat CYP2C11, CYP2E1 and human CYP1A2 in the p-hydroxylation of o-phenylphenol is suggested. 2. 2,3- and phenylhydroquinone, which induced DNA single-strand scission in the presence of 1 μM CuCl2, were the most cytotoxic chemicals examined to cultured mammalian cell lines among o-phenylphenol, m-phenylphenol, p-phenylphenol, 2,2'-, 4,4'-, 2,3- and phenylhydroquinone. 3. Rat and human liver microsomes catalysed the formation of phenylhydroquinone, but not 2,3-dihydroxybiphenyl, using o-phenylphenol as a substrate. A higher rate of metabolic activation of o-phenylphenol was observed with livers of the male than the female rats by 5.6- and 2.6-fold respectively. 4. Inhibitory antibodies against the male-specific CYP2C11 inhibited hepatic o-phenylphenol p-hydroxylation in the male F344 and Sprague-Dawley rat by > 70 %. Liver microsomes from the isoniazid-treated rats produced 1.8- and 3-fold induction of o-phenylphenol p-hydroxylation and chlorzoxazone 6-hydroxylation (a CYP2E1-dependent activity) respectively. 5. Human CYP1A2, expressed by baculovirus-mediated cDNA expression systems, exhibited a remarkably higher capacity for o-phenylphenol p-hydroxylation at concentrations of 5 (> 5-fold), 50 (> 2-fold) and 500 μM (> 2-fold) than CYP2A, CYP2B, CYP2Cs, CYP2D6, CYP2E1 and CYP3A4 on the basis of pmol P450. 6. Among various CYP inhibitors tested here, 7,8-benzoflavone and furafylline, typical human CYP1A2 inhibitors, inhibited the microsomal p-hydroxylation of o-phenylphenol in human livers most potently by 70 and 50 % respectively. 7. The results thus indicate the involvement of rat CYP2C11/CYP2E1 and human CYP1A2 in the hepatic p-hydroxylation of o-phenylphenol.
A dinuclear iron(II) complex bearing multidentate pyridinyl ligand: Synthesis, characterization and its catalysis on the hydroxylation of aromatic compounds
Gu, Erxing,Zhong, Wei,Ma, Hongxia,Xu, Beibei,Wang, Hailong,Liu, Xiaoming
, p. 159 - 165 (2018/03/29)
A dinuclear iron(II) complex Fe2L2(μ2-Cl)2Cl2 (L = N,N-bis(pyridin-2-ylmethyl)prop-2-yn-1-amine) was prepared and fully characterized by UV–Vis spectroscopy, elemental analysis, electrochemical analysis and X-ray single crystal diffraction analysis. The catalytic activity of the complex was assessed for the hydroxylation of aromatic compounds by using aqueous H2O2 as an oxidant in acetonitrile. The catalytic system was applicable in a wide range of substrates including aromatic compounds with both electron-donating and electron-withdrawing substituents and showed moderate to good catalytic activity and selectivity in the oxidation reactions. Particularly, in the case of benzene the selectivity of phenol achieve to 74% with the reaction conversion of 24.8%.
Reversible formation of aryloxenium ions from the corresponding quinols under acidic conditions
Chakraborty, Mrinal,Brzozowski, Christopher F.,Novak, Michael
, p. 1236 - 1242 (2013/08/24)
Quinols, 1, are products of the hydration of O-aryloxenium ions, 2, and N-arylnitrenium ions, 3, and they are being investigated for medical uses. Under acidic conditions (pH 1-3) kinetics and products of Br- trapping demonstrate that 1a, 4-phenyl-4-hydroxy-2,5-cyclohexadienone, and 1b, 4-p-tolyl-4-hydroxy-2,5-cyclohexadienone, generate the corresponding oxenium ions 2a and 2b, respectively, as steady-state intermediates. Formation and trapping of the oxenium ions occurs in competition with the acid catalyzed dienone-phenol rearrangement. Because oxenium ion formation is reversible, the ion can only be detected by trapping with a nucleophile. Br- is an efficient trap under acidic conditions because, unlike N3 -, it is not protonated under those conditions. Attempts to detect the oxenium ions 2a and 2b at pH 4.6 and 7.1 with N3- were unsuccessful indicating that oxenium ion formation only occurs under acidic conditions. The oxenium ion 2c could not be detected under acidic conditions from the quinol 1c, 4-(benzothiazol-2-yl)-4-hydroxy-2,5-cyclohexadienone, by Br- trapping methods, even though this ion can be detected during hydrolysis of the corresponding ester, 4c. Although the benzothiazol-2-yl group is a resonance electron donor that is capable of stabilizing an O-aryloxenium ion, it is also a strong inductive electron withdrawing group that hinders the formation of 2c from 1c by decreasing the extent of protonation of 1c to generate 1cH+ and by destabilizing the transition state for ionization of 1cH+. Generation of an oxenium ion from the corresponding quinol is feasible under acidic conditions as long as the 4-substituent of the quinol is both a resonance and inductive electron donor. Copyright
