- Direct Oxygenation of Benzene and Its Analogues into Phenols Catalyzed by Oxovanadium(IV) Complex with Combined Use of Molecular Oxygen and Aldehyde
-
In the presence of a catalytic amount of oxovanadium(IV) complexes coordinated by 1,3-diketone-type ligands, benzene and its analogues are directly oxygenated into phenols by combined use of molecular oxygen and crotonaldehyde at room temperature.
- Hata, Eiichiro,Takai, Toshihiro,Yamada, Tohru,Mukaiyama, Teruaki
-
-
Read Online
- Increasing the steric hindrance around the catalytic core of a self-assembled imine-based non-heme iron catalyst for C-H oxidation
-
Sterically hindered imine-based non-heme complexes4and5rapidly self-assemble in acetonitrile at 25 °C, when the corresponding building blocks are added in solution in the proper ratios. Such complexes are investigated as catalysts for the H2O2oxidation of a series of substrates in order to ascertain the role and the importance of the ligand steric hindrance on the action of the catalytic core1, previously shown to be an efficient catalyst for aliphatic and aromatic C-H bond oxidation. The study reveals a modest dependence of the output of the oxidation reactions on the presence of bulky substituents in the backbone of the catalyst, both in terms of activity and selectivity. This result supports a previously hypothesized catalytic mechanism, which is based on the hemi-lability of the metal complex. In the active form of the catalyst, one of the pyridine arms temporarily leaves the iron centre, freeing up a lot of room for the access of the substrate.
- Frateloreto, Federico,Capocasa, Giorgio,Olivo, Giorgio,Abdel Hady, Karim,Sappino, Carla,Di Berto Mancini, Marika,Levi Mortera, Stefano,Lanzalunga, Osvaldo,Di Stefano, Stefano
-
p. 537 - 542
(2021/02/09)
-
- Method for hydrolyzing diarylether compound to generate aryl phenol compound
-
The invention discloses a method for hydrolyzing a diarylether compound to generate an arylphenol compound. According to the method, visible light is utilized to excite a photosensitizer for catalysis. In a reaction solvent, the raw material in the formula (1) breaks a C (sp2)-O bond under the auxiliary action of acid, and hydrolysis is performed to obtain the bimolecular aryl phenol compounds in the formula (3) and the formula (4). The method can catalyze the reaction at room temperature, is green and environment-friendly, and is easy to operate; the universality is wide, the reaction yield is relatively high, and the tolerance of functional groups is strong; the synthesis method not only can realize small-scale hydrolysis conversion of various diarylether compounds, but also can realize hydrolysis of herbicidal ether, triclosan and a lignin template substrate, and even can realize large-scale hydrolysis of triclosan and the lignin template substrate to realize gram-level degradation. A new strategy is provided for recovering phenol derivatives through lignin hydrolysis, degrading pesticides and purifying wastewater containing a degerming agent or herbicide. The method has wide application prospect and use value.
- -
-
Paragraph 0139-0141
(2021/09/29)
-
- Preparation method of M-tert-butylphenol
-
The invention discloses a preparation method of m-tert-butylphenol. The preparation method comprises the following steps: with tert-butylbenzene as a raw material, nitrifying tert-butylbenzene to obtain 2,4-dinitro-tert-butylbenzene, then conducting reduction and Baberger rearrangement to obtain 2,4-diamino-3-hydroxy tert-butylbenzene, and finally, performing diazotizing and reducing to remove amino groups so as to obtain m-tert-butylphenol. According to a process route in the invention, para-isomer generation is effectively avoided, and m-tert-butylphenol with a purity of 99% or above can beobtained through simple distillation; and the method has the advantages that raw materials are cheap and easy to obtain, the process is simple and has few side reactions, and the method is suitable for industrial production.
- -
-
Paragraph 0011; 0013; 0016; 0017; 0020; 0021; 0024
(2021/03/31)
-
- Easy Synthesis of a Self-Assembled Imine-Based Iron(II) Complex Endowed with Crown-Ether Receptors
-
Herein we report that an imine-based iron complex decorated with crown-ether moieties self-assembles in CH3CN solution from three building blocks (namely Fe(CH3CN)2(OTf)2, 2-picolylamine and aldehyde 6a) added in the proper molar ratio (1:2:2, respectively). Aldehyde 6a, endowed with a benzocrown-ether receptor, can be prepared in two steps from commercial materials with high yields (79 percent) and no need of chromatographic separations. The self-assembled complex is highly stable in CH3CN solution. The complex has been tested as catalyst for the oxidation of aromatic compounds endowed with primary ammonium anchoring group with H2O2. An unexpected yet moderate selectivity for remote meta over ortho hydroxylation was obtained, which is mainly due to the steric hindrance of the catalyst.
- Capocasa, Giorgio,Di Berto Mancini, Marika,Di Stefano, Stefano,Frateloreto, Federico,Lanzalunga, Osvaldo,Olivo, Giorgio
-
-
- Green preparation process of M-tert-butylphenol
-
The invention discloses a preparation process of m-tert-butylphenol. The method includes the steps of: (1) adopting phenol and tert-butyl chloride as the raw materials, taking acidic clay and concentrated sulfuric acid as the catalyst, carrying out alkylation reaction to obtain the main product m-tert-butylphenol and the byproduct p-tert-butylphenol by one step, and performing separation; and (2)taking unreacted phenol and the p-tert-butylphenol by-product obtained in the step (1) as the raw materials, and taking acidic clay and aluminum trichloride as the catalyst, and carrying out rearrangement reaction to obtain m-tert-butylphenol in one step. Compared with the prior art, the preparation process of m-tert-butylphenol provided by the invention has the advantages of cheap and easily available raw materials, simple technology, good atom economy, greenness and environmental protection, is suitability for industrial production, and has important practical significance for improvement ofthe economic and social benefits of the tert-butylphenolation industry.
- -
-
Paragraph 0023; 0025; 0027; 0029; 0030; 0032
(2020/04/02)
-
- Synthesis of Highly Substituted Phenols and Benzenes with Complete Regiochemical Control
-
Substituted phenols are requisite molecules for human health, agriculture, and diverse synthetic materials. We report a chemical synthesis of phenols, including penta-substituted phenols, that accommodates programmable substitution at any position. This method uses a one-step conversion of readily available hydroxypyrone and nitroalkene starting materials to give phenols with complete regiochemical control and in high chemical yield. Additionally, the phenols can be converted into highly and even fully substituted benzenes.
- Zhang, Xiaojie,Beaudry, Christopher M.
-
supporting information
p. 6086 - 6090
(2020/08/12)
-
- METHOD FOR PREPARING P-HYDROXYMANDELIC COMPOUNDS IN STIRRED REACTORS
-
The process allows the preparation of a p-hydroxymandelic compound, comprising at least one step of condensation of at least one aromatic compound bearing at least one hydroxyl group and whose para position is free, with glyoxylic acid, the condensation reaction being performed in at least one reactor equipped with at least one mixing means, the specific mixing power being between 0.1 kW/m3 and 15 kW/m3. In addition, the invention also relates to a process for preparing a 4-hydroxyaromatic aldehyde by oxidation of this p-hydroxymandelic compound.
- -
-
-
- A synthesis method of uncle-butyl phenol
-
The invention relates to a method for synthesizing 3-(tert-butyl)phenol. The method includes the following steps that 4-tert-butyl-1-chlorobenzene serves as a raw material and is nitrated to obtain 1-chlorine-4-tert-butyl-2-nitrobenzene; the 1-chlorine-4-tert-butyl-2-nitrobenzene is reduced to generate 3-tert-butylaniline; the 3-tert-butylaniline is diazotized and subjected to a hydrolysis reaction, and the 3-(tert-butyl)phenol is obtained. According to the path, the raw material is cheap and easy to get, elementary reaction conditions of the steps are mild, after-treatment is simple, the four-step reaction total yield is high, the 3-(tert-butyl)phenol with the purity higher than 97% can be obtained through distilling, and industrial production prospects are achieved.
- -
-
-
- Highly Selective and Efficient Ring Hydroxylation of Alkylbenzenes with Hydrogen Peroxide and an Osmium(VI) Nitrido Catalyst
-
The OsVI nitrido complex, OsVI(N)(quin)2(OTs) (1, quin=2-quinaldinate, OTs=tosylate), is a highly selective and efficient catalyst for the ring hydroxylation of alkylbenzenes with H2O2 at room temperature. Oxidation of various alkylbenzenes occurs with ring/chain oxidation ratios ranging from 96.7/3.3 to 99.9/0.1, and total product yields from 93 % to 98 %. Moreover, turnover numbers up to 6360, 5670, and 3880 can be achieved for the oxidation of p-xylene, ethylbenzene, and mesitylene, respectively. Density functional theory calculations suggest that the active intermediate is an OsVIII nitrido oxo species.
- Kwong, Hoi-Ki,Lo, Po-Kam,Yiu, Shek-Man,Hirao, Hajime,Lau, Kai-Chung,Lau, Tai-Chu
-
p. 12260 - 12263
(2017/09/06)
-
- Synthesis of m-Alkylphenols via a Ruthenium-Catalyzed C-H Bond Functionalization of Phenol Derivatives
-
The first example of the synthesis of m-alkylphenols via a ruthenium-catalyzed CAr-H bond functionalization of phenol derivatives with sec/tert-alkyl bromides is reported. Mechanistic studies indicated that the m-CAr-H bond alkylation may involve a radical process and that a six-membered ruthenacycle complex was the active catalyst. Moreover, this approach can provide an expedited strategy for the atom-/step-economical synthesis of many noteworthy pharmaceuticals and other functional molecules.
- Li, Gang,Gao, Panpan,Lv, Xulu,Qu, Chen,Yan, Qingkai,Wang, Ya,Yang, Suling,Wang, Junjie
-
supporting information
p. 2682 - 2685
(2017/05/24)
-
- Meta-position alkylphenol synthesizing method
-
Disclosed is a meta-position alkylphenol synthesizing method. The meta-position alkylphenol synthesizing method is obtained through direct reaction of 2-(3-alkyl-phenoxy) pyridine and methyl trifluoromethansulfonate. The method comprises a reaction process of directly adding the 2-(3-alkyl-phenoxy) pyridine, the methyl trifluoromethansulfonate and methylbenzene into a reaction device; in a nitrogen atmosphere, performing stirring at 100 DEG C for reaction for 24 hours, and after the reaction is completed, separating out coarse products; adding the coarse products and sodium into methyl alcohol for refluxing for 15 minutes, and then performing separation to obtain meta-position alkylphenol compounds. The meta-position alkylphenol synthesizing method is reliable in raw material source and simple in reaction and is an economic and efficient meta-position alkylphenol preparing method.
- -
-
Paragraph 0011
(2017/09/01)
-
- Synthesis and Photocleavage of Quinoline Methyl Ethers: A Mild and Efficient Method for the Selective Protection and Deprotection of the Alcohol Functionality
-
The synthesis and photocleavage of quinolinyl methyl ether-protected alcohols is reported in this study. A variety of quinoline methyl chlorides were synthesized, and protection of the various alcohols was performed via a substitution reaction in the presence of a strong base. Photocleavage of the quinolinyl methyl ether moiety proceeded under visible light with the formation of the charged quinolinyl radical intermediate through a single-electron transfer in the presence of a photosensitizer dye leading to the deprotected alcohol in excellent yields. The utility of triethylamine as a sacrificial reductant and d-sorbitol as a radical scavenger were also investigated in this study.
- Provatas, Anthony A.,Epling, Gary A.,Stuart, James D.
-
p. 763 - 769
(2016/08/09)
-
- A dinuclear iron(II) complex bearing multidentate pyridinyl ligand: Synthesis, characterization and its catalysis on the hydroxylation of aromatic compounds
-
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%.
- Gu, Erxing,Zhong, Wei,Ma, Hongxia,Xu, Beibei,Wang, Hailong,Liu, Xiaoming
-
p. 159 - 165
(2018/03/29)
-
- CYCLIC PEROXIDE OXIDATION OF AROMATIC COMPOUND PRODUCTION AND USE THEREOF
-
The present invention provides a method for converting an aromatic hydrocarbon to a phenol by providing an aromatic hydrocarbon comprising one or more aromatic C-H bonds and one or more activated C-H bonds in a solvent; adding a phthaloyl peroxide to the solvent; converting the phthaloyl peroxide to a di-radical; contacting the di-radical with the one or more aromatic C-H bonds; oxidizing selectively one of the one or more aromatic C-H bonds in preference to the one or more activated C-H bonds; adding a hydroxyl group to the one of the one or more aromatic C-H bonds to form one or more phenols; and purifying the one or more phenols.
- -
-
Page/Page column 10
(2014/10/15)
-
- Base-catalyzed dehydration of 3-substituted benzene cis -1,2-dihydrodiols: Stabilization of a cyclohexadienide anion intermediate by negative aromatic hyperconjugation
-
Evidence that a 1,2-dihydroxycyclohexadienide anion is stabilized by aromatic "negative hyperconjugation" is described. It complements an earlier inference of "positive" hyperconjugative aromaticity for the cyclohexadienyl cation. The anion is a reactive intermediate in the dehydration of benzene cis-1,2-dihydrodiol to phenol. Rate constants for 3-substituted benzene cis-dihydrodiols are correlated by σ- values with = 3.2. Solvent isotope effects for the reactions are kH2O/kD 2O = 1.2-1.8. These measurements are consistent with reaction via a carbanion intermediate or a concerted reaction with a "carbanion-like" transition state. These and other experimental results confirm that the reaction proceeds by a stepwise mechanism, with a change in rate-determining step from proton transfer to the loss of hydroxide ion from the intermediate. Hydrogen isotope exchange accompanying dehydration of the parent benzene cis-1,2-dihydrodiol was not found, and thus, the proton transfer step is subject to internal return. A rate constant of ～1011 s-1, corresponding to rotational relaxation of the aqueous solvent, is assigned to loss of hydroxide ion from the intermediate. The rate constant for internal return therefore falls in the range 1011-1012 s -1. From these limiting values and the measured rate constant for hydroxide-catalyzed dehydration, a pKa of 30.8 ± 0.5 was determined for formation of the anion. Although loss of hydroxide ion is hugely exothermic, a concerted reaction is not enforced by the instability of the intermediate. Stabilization by negative hyperconjugation is proposed for 1,2-dihydroxycyclohexadienide and similar anions, and this proposal is supported by additional experimental evidence and by computational results, including evidence for a diatropic ("aromatic") ring current in 3,3-difluorocyclohexadienyl anion.
- Kudavalli, Jaya Satyanarayana,Rao, S. Nagaraja,More Oferrall, Rory A.,Bean, David E.,Fowler, Patrick W.,Sharma, Narain D.,Boyd, Derek R.,Kamerlin, Shina Caroline Lynn,Keeffe, James R.,Gronert, Scott
-
supporting information
p. 14056 - 14069,14
(2020/08/31)
-
- Chemo- and regioselective direct hydroxylation of arenes with hydrogen peroxide catalyzed by a divanadium-substituted phosphotungstate
-
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
- Kamata, Keigo,Yamaura, Taiyo,Mizuno, Noritaka
-
supporting information; experimental part
p. 7275 - 7278
(2012/08/28)
-
- The Ever-surprising chemistry of boron: Enhanced acidity of phosphine·boranes
-
The gas-phase acidity of a series of phosphines and their corresponding phosphine·borane derivatives was measured by FT-ICR techniques. BH 3 attachment leads to a substantial increase of the intrinsic acidity of the system (from 80 to 110 kJ mol-1). This acidity-enhancing effect of BH3 is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. This indicates that the enhancement of the acidity of protic acids by Lewis acids usually observed in solution also occurs in the gas phase. High- level DFT calculations reveal that this acidity enhancement is essentially due to stronger stabilization of the anion with respect to the neutral species on BH3 association, due to a stronger electron donor ability of P in the anion and better dispersion of the negative charge in the system when the BH3 group is present. Our study also shows that deprotonation of ClCH2PH2 and ClCH 2PH2·BH3 is followed by chloride departure. For the latter compound deprotonation at the BH3 group is found to be more favorable than PH2 deprotonation, and the subsequent loss of Cl- is kinetically favored with respect to loss of Cl - in a typical SN2 process. Hence, ClCH2PH 2·BH3 is the only phosphine·borane adduct included in this study which behaves as a boron acid rather than as a phosphorus acid.
- Hurtado, Marcela,Yanez, Manuel,Herrero, Rebeca,Guerrero, Andres,Juan Z. Davalos,Jose-Luis, M. Abboud,Khater, Brahim,Guillemin, Jean-Claude
-
supporting information; experimental part
p. 4622 - 4629
(2009/12/29)
-
- Process for functionalising a phenolic compound carrying an electron-donating group
-
The invention concerns a method for functionalizing a phenolic compound bearing an electron-donor group, in said group para position, inter alia a method for the amidoalkylation of a phenolic compound bearing an electron-donor group, and more particularly, a phenolic compound bearing an electron-donor group preferably, in the hydroxyl group ortho position. The method for functionalizing in para position with respect to an electron-donor group carried by a phenolic compound is characterised in that the phenolic compound bearing an electron-donor group is subjected to the following steps: a first step which consists of protecting the hydroxyl group in the form of a sulphonic ester function; a second step which consists in reacting the protected phenolic compound with an electrophilic reagent; optionally, a third step deprotecting the hydroxyl group.
- -
-
-
- O-alkylation of phenolic compounds via rare earth orthophosphate catalysts
-
Carbocyclic/aliphatic ethers, for example anisole, quaicol, guaethol, p-methoxyphenol and ethylene dioxybenzene, are selectively prepared, in good yield, by reacting a phenolic compound, for example a phenol, hydroquinone, pyrocatechin, naphthol, or the like, with an alcohol, for example methanol, ethanol, isopropanol, ethylene glycol, etc., in gaseous phase, in the presence of a catalytically effective amount of a trivalent rare earth metal orthophosphate, for example a lanthanum, cerium or samarium orthophosphate, optionally doped with an alkali or alkaline earth metal, preferably cesium.
- -
-
-
- Ester Cleavage by Cyclodextrins in Aqueous Dimethyl Sulfoxide Mixtures. Substrate Binding versus Transition State Binding
-
The effects of DMSO on the kinetics of cleavage of m- and p-nitrophenyl alkanoates (mNPAlk and pNPAlk) by α- and β-cyclodextrin (α-CD and β-CD) in basic aqueous solution have been studied.For the two acetates addition of up to 60percent (v/v) of DMSO increases rates but overall it has little effect on substrate binding, transition state binding, or the acceleration due to complexation.By contrast, in 50percent (v/v) aqueous DMF these characteristics are greatly affected such that the normal difference in reactivity of the isomers is almost removed.The cleavage of mNPAlk and pNPAlk (C2 to C10) by the CDs in 60percent (v/v) aqueous DMSO have very different chain length dependences for substrate binding and transition state binding, and there are significant changes from their behavior in water.Even though hydrophobic effects seem to be largely removed in 60percent aqueous DMSO, and the difference between the reactivities of the isomers is reduced, reaction of mNPAlk proceeds through aryl group inclusion and that of pNPAlk through acyl group inclusion, as in water.The cleavage of m-tert-butylphenyl acetate is accelerated more in 60percent (v/v) aqueous DMSO than in water because the solvent change weakens substrate binding more than transition state binding.
- Tee, Oswald S.,Mazza, Charles,Lozano-Hemmer, Rafael,Giorgi, Javier B.
-
p. 7602 - 7608
(2007/10/02)
-
- Preparation of diphenolics
-
A process for the production of diphenolic compounds having a divalent bridge. A first disubstituted phenol is reacted with an aldehyde in the presence of a secondary amine and excess alcohol to form an ether intermediate. The ether intermediate is reacted with a phenol having an open ortho or para position to form a diphenolic.
- -
-
-
- Preparation of aromatic amines
-
Aromatic amines (anilines) are obtained directly or via the corresponding cycloaliphatic amines by an aminating/hydrogenating reaction of phenols with ammonia and hydrogen over a supported palladium catalyst which also contains elements from group 1b, 2b or 7b of the periodic table as well as iron, cobalt or nickel, as such or in the form of their compounds, and, preferably, an inorganic base, said catalysts also having dehydrogenating properties.
- -
-
-
- DIRECT HYDROXYLATION OF COMPOUNDS IN AN RF PLASMA
-
The hydoxylation of aromatic compounds was carried out in the plasma generated by a radiofrequency discharge.Benzene and naphthalene yielded phenol and naphthols, respectively, as single volatile products.With respect to alkylbenzenes, the oxidation of the side-chains competed with the aromatic hydroxylation.
- Tezuka, Meguru,Yajima, Tatsuhiko,Tsuchiya, Atsuhiko
-
p. 1437 - 1438
(2007/10/02)
-
- Improved Acylation Rates within Cyclodextrin Complexes from Flexible Capping of the Cyclodextrin and from Adjustment of the Substrate Geometry
-
The acylation of β-cyclodextrin by bound substrates has been studied as a model for serine acylase enzymes such as chymotrypsin.Molecular model building suggested that previously examined substrates, which had given acylation rates only a few hundred times accelerated over the hydrolysis rates, were not optimal geometrically.In our work the geometry for such processes has been improved by fashioning an "intrusive floor" on the cyclodextrin cavity, leading to improved rates.Greater improvements have come from substrate modification, using substrates based on the cinnamic acid, adamantane, and ferrocene frameworks.The rates correlate well with the geometric predictions from molecular models.The best case leads to an acceleration of acylation, relative to hydrolysis, of 106-107-fold, exceeding that for chymotrypsin with p-nitrophenyl acetate.
- Breslow, Ronald,Czarniecki, Michael F.,Emert, Jack,Hamaguchi, Hiroshi
-
p. 762 - 770
(2007/10/02)
-
