133083-17-7Relevant articles and documents
Catalytic oxygenation of various monophenols by copper(I) complexes with bis(pyrazolyl)methane ligands: Differences in reactivity
Hamann, Jessica Nadine,Schneider, Rebecca,Tuczek, Felix
, p. 3259 - 3271 (2015)
Three new mononuclear copper(I) complexes supported by the symmetric ligands 1,1′-methylenebis-1H-pyrazole (BPM), 1,1′-methylenebis(3-methyl-1H-pyrazole) (mBPM), and 1,1′-methylenebis(3,5-di-methyl-1H-pyrazole) (dmBPM) were synthesized as catalytic model systems of tyrosinase. The influence of various functional groups on the catalytic conversion of monophenols is investigated and the formation of the corresponding ortho-quinones is monitored using UV/vis and NMR spectroscopy. Comparison of various monophenols reveals the differences in reactivity which are analyzed and interpreted based on key intermediates of the mechanistic cycle.
Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure–reactivity correlations
Wendt, Franziska,N?ther, Christian,Tuczek, Felix
, p. 777 - 792 (2016)
Four new imidazole-based ligands, 4-((1H-imidazol-4-yl)methyl)-2-phenyl-4,5-dihydrooxyzole (LOL1), 4-((1H-imidazol-4-yl)methyl)-2-(tert-butyl)-4,5-dihydrooxyzole (LOL2), 4-((1H-imidazol-4-yl)methyl)-2-methyl-4,5-dihydrooxyzole (LOL3), and N-(2,2-dimethylpropylidene)-2-(1-trityl-1H-imidazol-4-yl-)ethyl amine (Limz1), have been synthesized. The corresponding copper(I) complexes [Cu(I)(LOL1)(CH3CN)]PF6 (CuLOL1), [Cu(I)(LOL2)(CH3CN)]PF6 (CuLOL2), [Cu(I)(LOL3)(CH3CN)]PF6 (CuLOL3), [Cu(I)(Limz1)(CH3CN)2]PF6 (CuLimz1) as well as the Cu(I) complex derived from the known ligand bis(1-methylimidazol-2-yl)methane (BIMZ), [Cu(I)(BIMZ)(CH3CN)]PF6 (CuBIMZ), are screened as catalysts for the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC-H2) to 3,5-di-tert-butylquinone (3,5-DTBQ). The primary reaction product of these oxidations is 3,5-di-tert-butylsemiquinone (3,5-DTBSQ) which slowly converts to 3,5-DTBQ. Saturation kinetic studies reveal a trend of catalytic activity in the order CuLOL3?≈?CuLOL1?>?CuBIMZ?>?CuLOL2?>?CuLimz1. Additionally, the catalytic activity of the copper(I) complexes towards the oxygenation of monophenols is investigated. As substrates 2,4-di-tert-butylphenol (2,4-DTBP-H), 3-tert-butylphenol (3-TBP-H), 4-methoxyphenol (4-MeOP-H), N-acetyl-l-tyrosine ethyl ester monohydrate (NATEE) and 8-hydroxyquinoline are employed. The oxygenation products are identified and characterized with the help of UV/Vis and NMR spectroscopy, mass spectrometry, and fluorescence measurements. Whereas the copper complexes with ligands containing combinations of imidazole and imine functions or two imidazole units (CuLimz1 and CuBIMZ) are found to exhibit catalytic tyrosinase activity, the systems with ligands containing oxazoline just mediate a stoichiometric conversion. Correlations between the structures of the complexes and their reactivities are discussed.
Catalytic phenol hydroxylation with dioxygen: Extension of the tyrosinase mechanism beyond the protein matrix
Hoffmann, Alexander,Citek, Cooper,Binder, Stephan,Goos, Arne,Ruebhausen, Michael,Troeppner, Oliver,Ivanovic-Burmazovic, Ivana,Wasinger, Erik C.,Stack, T. Daniel P.,Herres-Pawlis, Sonja
supporting information, p. 5398 - 5401 (2013/06/27)
A new catalyst (see structure) hydroxylates phenols with O2 via a stable side-on peroxide complex, which is similar to the active site of tyrosinase in terms of the ligand environment and its spectroscopic properties. The catalytic oxidation of phenols to quinones proceeds at room temperature in the presence of NEt3 and even non-native substrates can be oxidized catalytically. The reaction mechanism is analogous to that of the enzyme-catalyzed reaction. Copyright
