C:Corrosive;
98-29-3Relevant academic research and scientific papers
Indirect inactivation of tyrosinase in its action on 4-tert-butylphenol
Mu?oz-Mu?oz, Jose Luis,García-Molina, María Del Mar,García-Molina, Francisco,Varon, Ramón,García-Ruiz, Pedro Antonio,Rodríguez-López, Jose Neptuno,García-Cánovas, Francisco
, p. 344 - 352 (2014)
Under anaerobic conditions, the o-diphenol 4-tert-butylcatechol (TBC) irreversibly inactivates met and deoxytyrosinase enzymatic forms of tyrosinase. However, the monophenol 4-tert-butylphenol (TBF) protects the enzyme from this inactivation. Under aerobic conditions, the enzyme suffers suicide inactivation when it acts on TBC. We suggest that TBF does not directly cause the suicide inactivation of the enzyme in the hydroxylase activity, but that the o-diphenol, which is necessary for the system to reach the steady state, is responsible for the process. Therefore, monophenols do not induce the suicide inactivation of tyrosinase in its hydroxylase activity, and there is a great difference between the monophenols that give rise to unstable o-quinones such as L-tyrosine, which rapidly accumulate L-dopa in the medium and those like TBF, after oxidation, give rise to a very stable o-quinone.
Metal chlorides or sulfuric acid in ionic liquid solvents convert catechol to p-tert-Butylcatechol
Zhang, Wenlin,Yue, Ying,Su, Weiyi,Du, Wei,Wang, Xiaowen,Zhu, Guanyu,Li, Chunli
, p. 113 - 116 (2015)
A series of novel acidic ionic liquids (ILs) mediated in metal chloride or sulfuric acid (IL-RClx or IL-H2SO4, R = Na, K, Al, Ba, Ca) were investigated as catalysts in the alkylation of catechol and methyl tert-butyl ether to p-tert-Butylcatechol. Based on the ILs screening, it was found that N-(4-sulfonic acid butyl) pyridine hydrogen bisulfate (IL2) was the most efficient catalyst (in the reaction). Moreover IL2 modified by sulfuric acid showed the best performance with the yield of p-tert-Butylcatechol approximately 81.7% and the selectivity of 92.5%. For a clear perspective to the influence of H2SO4, IL2 ([C4SO3HPy]HSO4) was systematically studied by the Density Functional Theory at 6-31 + G? level and the results showed that hydrogen bonds inside the ILs were probably the key for acidity enhancement of the modifications.
Ortho-Hydroxylation of 4-tert-butylphenol by nonheme iron(III) complexes as a functional model reaction for tyrosine hydroxylase
Funabiki, Takuzo,Yokomizo, Tomomasa,Suzuki, Shinko,Yoshida, Satohiro
, p. 151 - 152 (1997)
Hydroxylation of 4-tert-butylphenol to 4-tert-butylcatechol is performed by a catecholatoiron(III) complex-hydroquinone-O2 system which mimicks the roles of Fe2+ and Fe3+ in tyrosine hydroxylase; the ortho-hydroxylation of phenols by iron-oxygen active species is suggested.
1-Methyl-1,4-cyclohexadiene as a Traceless Reducing Agent for the Synthesis of Catechols and Hydroquinones
Baschieri, Andrea,Amorati, Riccardo,Valgimigli, Luca,Sambri, Letizia
, p. 13655 - 13664 (2019/10/28)
Pro-aromatic and volatile 1-methyl-1,4-cyclohexadiene (MeCHD) was used for the first time as a valid H-atom source in an innovative method to reduce ortho or para quinones to obtain the corresponding catechols and hydroquinones in good to excellent yields. Notably, the excess of MeCHD and the toluene formed as the oxidation product can be easily removed by evaporation. In some cases, trifluoroacetic acid as a catalyst was added to obtain the desired products. The reaction proceeds in air and under mild conditions, without metal catalysts and sulfur derivatives, resulting in an excellent and competitive method to reduce quinones. The mechanism is attributed to a radical reaction triggered by a hydrogen atom transfer from MeCHD to quinones, or, in the presence of trifluoroacetic acid, to a hydride transfer process.
Direct Synthesis of Hydroquinones from Quinones through Sequential and Continuous-Flow Hydrogenation-Derivatization Using Heterogeneous Au–Pt Nanoparticles as Catalysts
Miyamura, Hiroyuki,Tobita, Fumiya,Suzuki, Aya,Kobayashi, Shū
supporting information, p. 9220 - 9224 (2019/06/13)
Pt–Au bimetallic nanoparticle catalysts immobilized on dimethyl polysilane (Pt–Au/(DMPSi-Al2O3)) have been developed for selective hydrogenation of quinones to hydroquinones. High reactivity, selectivity, and robustness of the catalysts were confirmed under continuous-flow conditions. Various direct derivatizations of quinones, such as methylation, acetylation, trifluoromethanesulfonylation, methacrylation, and benzoylation were successfully performed under sequential and continuous-flow conditions to afford the desired products in good to excellent yields. Especially, air-sensitive hydroquinones, such as anthrahydroquinones and naphthohydroquinones, could be successfully generated and derivatized under closed sequential and continuous-flow conditions without decomposition.
Synthesis of α-oxygenated ketones and substituted catechols via the rearrangement of N-enoxy- and N-aryloxyphthalimides
Kroc, Michelle A.,Patil, Aditi,Carlos, Anthony,Ballantine, Josiah,Aguilar, Stephanie,Mo, Dong-Liang,Wang, Heng-Yen,Mueller, Daniel S.,Wink, Donald J.,Anderson, Laura L.
, p. 4125 - 4137 (2017/06/29)
A common approach to the synthesis of α-oxygenated carbonyl compounds and catechols is the treatment of a carbonyl compound or a phenol with an electrophilic oxygen source. As an alternative approach to these important structures, formal [3,3]-rearrangements of N-enoxyphthalimides, N-enoxyisoindolinones, and N-aryloxyphthalimides have been explored. When used in combination with an initial Chan-Lam coupling, these transformations facilitate the dioxygenation of alkenylboronic acids for the synthesis of α-oxygenated ketones and the dioxygenation of arylboronic acids for the synthesis of catechols. The rearrangements of N-enoxyisoindolinones have also been shown to be diastereoselective.
Catalytic conversion of 4-tert-butylphenol in hydrogen peroxide solutions in the presence of titanium oxide compounds and titanosilicates
Talipova,Kharrasov,Veklov,Badikova,Kutepov
, p. 395 - 402 (2017/07/05)
The catalytic conversion of 4-tert-butylphenol (TBP) in hydrogen peroxide solutions in the presence of titanium oxide samples with different phase compositions and crystalline and amorphous titanosilicate samples has been studied. It has been shown that microporous crystalline titanosilicate TS-1 exhibits low activity in the TBP conversion owing to steric restrictions to the diffusion of the substrate molecules to catalytically active sites. The samples of titanium oxide compounds and mesoporous titanosilicates exhibit similar activity, while the selectivity of the latter for 4-tert-butylcatechol (TBC) is higher. The effect of the mesoporous titanosilicate concentration in the reaction mixture and the test temperature and duration on the TBP conversion and the TBC selectivity has been determined.
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%.
Spectroscopic and computational investigations of the thermodynamics of boronate ester and diazaborole self-assembly
Goldberg, Alexander R.,Northrop, Brian H.
, p. 969 - 980 (2016/02/18)
The solution phase self-assembly of boronate esters, diazaboroles, oxathiaboroles, and dithiaboroles from the condensation of arylboronic acids with aromatic diol, diamine, hydroxythiol, and dithiol compounds in chloroform has been investigated by 1H NMR spectroscopy and computational methods. Six arylboronic acids were included in the investigations with each boronic acid varying in the substituent at its 4-position. Both computational and experimental results show that the para-substituent of the arylboronic acid does not significantly influence the favorability of forming a condensation product with a given organic donor. The type of donor, however, greatly influences the favorability of self-assembly. 1H NMR spectroscopy indicates that condensation reactions between arylboronic acids and catechol to give boronate esters are the most favored thermodynamically, followed by diazaborole formation. Computational investigations support this conclusion. Neither oxathiaboroles nor dithiaboroles form spontaneously at equilibrium in chloroform at room temperature. Computational results suggest that the effect of borylation on the frontier orbitals of each donor helps to explain differences in the favorability of their condensation reactions with arylboronic acids. The results can inform the use of boronic acids as they are increasingly utilized in the dynamic self-assembly of organic materials and as components in dynamic combinatorial libraries.
A Catalyst-Controlled Aerobic Coupling of ortho-Quinones and Phenols Applied to the Synthesis of Aryl Ethers
Huang, Zheng,Lumb, Jean-Philip
supporting information, p. 11543 - 11547 (2016/11/17)
ortho-Quinones are underutilized six-carbon-atom building blocks. We herein describe an approach for controlling their reactivity with copper that gives rise to a catalytic aerobic cross-coupling with phenols. The resulting aryl ethers are generated in high yield across a broad substrate scope under mild conditions. This method represents a unique example where the covalent modification of an ortho-quinone is catalyzed by a transition metal, creating new opportunities for their utilization in synthesis.
