- A new metal-free access to vitamin K3
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2-Methylnaphthalene is oxidized in about 80% yield with 7-9/1 regioselectivity to 2-methyl-1,4-naphthoquinone by hydrogen peroxide with a strong mineral acid as the catalyst. No (transition) metal catalyst is required for this transformation.
- Bohle, Anne,Schubert, Anett,Sun, Yu,Thiel, Werner R.
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- Catalytic synthesis of 2-methyl-1,4-naphthoquinone (vitamin K3) over silica-supported aminomethyl phosphine-Ru(II), Pd(II), and Co(II) complexes
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Ru(II), Pd(II), and Co(II) complexes of the free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl) aminopropyltriethoxysilane [(EtO)3Si(CH2)3 N(CH2PPh2)2] (DIPAPTES), and its SiO2-DIPAPES have been synthesized under a nitrogen atmosphere using Schlenk techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to give 2-methyl-1,4-naphthoquinone (vitamin K3, menadione, 2MNQ) in the presence of hydrogen peroxide as a clean and cheap oxidant. The catalytic synthesis of vitamin K3 was investigated using both homogeneous catalysis with free complexes and heterogeneous catalysis with silica-supported complexes. [(DIPAPTES)PdCl2] and its silica-supported form showed the best catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphtoquinone compared to the other metal complexes. 2MNQ yield reached 52.26% with the 2MN conversion of 90.52% using complex [(DIPAPTES)PdCl2] and 58.59% with the 2MN conversion of 99.56% using the silica supported [SiO2(DIPAPES)PdCl2] complex for 1 h. Recycling was investigated for the silica-supported Pd(II) complex and compared with the classical production of vitamin K3. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Urus, Serhan,Keles, Mustafa,Serindag, Osman
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- An Experimental Test of the Competition Correction for Charge Capture from the Matrix in Intermolecular Electron Tunnelling Reactions
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Further experimental tests have been made of a previously presented method to correct for competition for charge capture from the matrix in intermolecular electron transfer (ET) reactions in rigid media.The method is based on a two-step tunnelling model which takes into account the correlation between matrix charge capture and intermolecular electron transfer.The goal is to obtain reliable intermolecular ET rates as a function of distance from measurements on rigid solutions containing two randomly distributed solutes.The method should yield the same rate vs. distance function for different donor solute concentrations.Good agreement was obtained by applying the competition correction to pulse radiolysis data for the reaction of the biphenyl anion with 2-methyl-1,4-naphthoquinone in 2-methyltetrahydrofuran (MTHF) at 77 K for donor:acceptor solute concentration ratios of 20:1 to 2:1.Worse agreement was obtained for the reaction of biphenyl anion with phenanthrene in MTHF, in which case the reaction is slow, and its energetics are substantially influenced by solvation.For such slow reactions, accurate measurements of intermolecular ET rates require donor:acceptor solute concentration ratios such that the donor solute captures most of the matrix charges.It was observed that some biphenyl cations are produced by direct ionizations and are stable in frozen MTHF.
- Huddleston, R. Kurt,Miller, John R.
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- Selective synthesis of vitamin K3 over mesoporous NbSBA-15 catalysts synthesized by an efficient hydrothermal method
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Well hexagonally ordered NbSBA-15 catalysts synthesized by an efficient hydrothermal method were used, for the first time, for the selective synthesis of vitamin K3 by liquid-phase oxidation of 2-methyl-1-naphthol (2MN1-OH) under various reaction conditions. The recyclable NbSBA-15 catalysts were also reused to find their catalytic activities. To investigate the leaching of non-framework niobium species on the surface of silica networks, the results of original and recyclable NbSBA-15 catalysts were correlated and compared. To find an optimum condition for the selective synthesis of vitamin K3, the washed NbSBA-15(2.2pH) was extensively used in this reaction with various reaction parameters such as temperature, time and ratios of reactant (2M1N-OH to H2O2), and the obtained results were also demonstrated. Additionally, the liquid-phase oxidation of 2M1N-OH was carried out with different solvents to find the best solvent with a good catalytic activity. Based on the all catalytic studies, the vitamin K3 selectivity (97.3%) is higher in NbSBA-15(2.2pH) than that of other NbSBA-15 catalysts, and the NbSBA-15(2.2pH) is found to be a highly active and eco-friendly heterogeneous catalyst for the selective synthesis of vitamin K3.
- Selvaraj,Park,Kim,Kawi,Ha
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- Manganese(II) naphthenate as effective catalyst for the clean oxidation of 2-methylnaphthalene by hydrogen peroxide
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Oxidation of 2-methylnaphthalene (2-MN) with aqueous hydrogen peroxide was conducted in acetic acid. The epoxidation pathway was investigated by increasing the CH3CO3H content and adding manganese(II) naphthenate (MnPc) as catalyst. 2-Methyl-1,4-naphthoquinone was obtained in 75.6% conversion and with 80.0% selectivity under the latter conditions. A probable mechanism in which MnPc catalyzes the oxidation of 2-MN by hydrogen peroxide in acetic acid is proposed. Springer Science+Business Media B.V. 2012.
- Yan, Tingfeng,Hong, Mei,Niu, Lei,Jiang, Feng,Xiao, Guomin
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- Synthesis of crab type Aminomethyldiphosphine-Oxovanadium(IV) complexes supported on magnetic Nano particles: Selective and recoverable catalysts in vitamin K3 synthesis
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Nano Fe3O4 particles were obtained in microvawe oven using closed system. Oxovanadium(IV) complexes of Fe3O4@SiO2@(aminomethylphosphine) type ligands were synthesized and characterized using SEM, EDX, TEM, UV-Visible, XRD, FT-IR and TG/DTA techniques. Catalytic properties of the synthesized pincer type oxovanadium(IV)-aminomethylphosphine complexes supported on magnetic nano structure were investigated in the synthesis of 2-methyl-1, 4-naphthoquinone (Vitamin K3, menadione, 2MNQ) from 2-methyl naphthalene (2MN) in hydrogen peroxide, acetic acid and sulfuric acid. Magnetic-nano particle supported oxovanadium(IV)-aminomethylphosphine type complexes were very efficient catalysts with the 51.36-55.20 % selectivities in conversions of 89.78-95.01 %. Besides, the hetergeneous complexes were very active in five cycling tests on avarage evaluated in the reusability.
- Uru?, Serhan,?aylar, Mahmut,Ko?er, Ferudun
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- OXIDATION OF 2-METHYLNAPHTHALENE TO 2-METHYL-1,4-NAPHTHOQUINONE WITH HYDROGEN PEROXIDE IN THE PRESENCE OF Pd(II)-POLYSTYRENE SULFONIC ACID RESIN
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The oxidation of 2-methylnaphthalene was carried out in acetic acid with aqueous(60percent) hydrogen peroxide in the presence of Pd(II)-polystyrene sulfonic acid resin. 2-Methyl-1,4-naphthoquinone was obtained in a yield of 50 to 60percent at 50 deg C for 8 h.The catalysts recovered by the filtration were reusable.
- Yamaguchi, Satoru,Inoue, Masami,Enomoto, Saburo
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- Preparation of Vitamin K3 in Mo–V–P Heteropoly Acid Solutions by Diene Synthesis
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Abstract: The possibility of obtaining vitamin K3 (2-methyl-1,4-naphthoquinone, menadione) by diene synthesis from accessible substrates such as 2-methylphenol (o-cresol) and 2-methylaniline (o-toluidine) was shown. The bifunctional catalysts of these processes are the aqueous solutions of Mo–V–P heteropoly acids, which allow the oxidation and diene synthesis to be performed as a one-pot process.
- Gogin, L. L.,Zhizhina, E. G.
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- Oxidation of 1,2,4-trimethylbenzene (TMB), 2,3,6-trimethylphenol (TMP) and 2-methylnaphthalene to 2,3,5-trimethylbenzoquinone (TMBQ) and menadione (vitamin K3)
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The synthesis of industrially important quinones as intermediates for vitamin syntheses is reviewed with special emphasis on recent developments in our own group.
- M?ller, Konstanze,Wienh?fer, Gerrit,Westerhaus, Felix,Junge, Kathrin,Beller, Matthias
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- Liquid phase oxidation of 2-methylnaphthalene to 2-methyl-1,4- naphthoquinone over lanthanum doped MCM-41
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Liquid phase oxidation of 2-methylnaphthalene was carried out under mild reaction conditions over lanthanum doped MCM-41 using aqueous hydrogen peroxide (30%) as oxidant and acetic acid as solvent without adding any initiator. The catalyst exhibited very high substrate conversion (95.8%) and reasonable product (2-methyl-1,4-naphthoquinone) selectivity (69.3%) under mild condition. Fast hot catalyst filtration experiment proved that the catalyst acted as a heterogeneous one and it can be reused two times without losing its activity to a greater extent. A possible mechanism was proposed.
- Zi, Guoli,Chen, Daomei,Li, Bin,Li, Zhiqiang,Luo, Xia,Zhang, Jinping,Li, Lin,Wang, Jiaqiang
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- Metalloporphyrin-catalyzed oxidation of 2-methylnaphthalene to vitamin K3 and 6-methyl-1,4-naphthoquinone by potassium monopersulfate in aqueous solution
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The metalloporphyrin-catalyzed oxidation of 2-methylnaphthalene (1) by potassium monopersulfate produced mainly two naphthoquinones: 2-methyl-1,4-naphthoquinone (2) (menadione or vitamin K3) and 6-methyl-1,4-naphthoquinone (3). In aqueous solution and at room temperature in the presence of 5 mol % of the water-soluble metalloporphyrins MnTPPS or FeTMPS, 2-methylnaphthalene was quantitatively oxidized to quinones 2 and 3. Based on experiments performed in 18O-labeled water and according to the 'redox tautomerism' mechanism previously described for such catalysts, the oxidation to quinones is proposed to be mainly due to a cytochrome P-450-type oxygenation reaction (oxygen atom transfer), rather than a peroxidase-type oxidation (electron transfer).
- Song, Rita,Sorokin, Alexander,Bernadou, Jean,Meunier, Bernard
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- Highly efficient selective oxidation of 2-methylnaphthalene to vitamin K3 over mesoporous Al/Ti-SBA-15 catalysts: The effect of acid sites and textural property
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Catalytic oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone (vitamin K3) is a significant pathway to produce vitamin groups K. High pollution and low-productivity of the traditional method require a greener catalyst and process. In this work, Al/Ti-SBA-15 with different nSi/nAl and nSi/nTi ratios were hydrothermally prepared in mild acidic condition and tested in partial oxidation of 2-methylnaphthalene. Commercial zeolites NaY, β and ZSM-5 were applied to investigate the influence of mass transfer resistance and acidity on catalytic performance. Catalysts were characterized by XRD, N2 adsorption-desorption, TEM, NH3-TPD, FTIR and Py-FTIR. We have found that the 2-methylnaphthalene conversion and vitamin K3 selectivity depend strongly on the mesoporous structure as well as Br?nsted acid concentration and strength. Irregular micropores and strong acidity will accelerate the cleavage of C = C in aromatic rings, leading to the production of phthalic anhydride. DFT calculation reveals that incorporation of aluminum in SBA-15 can reduce the energy gap, facilitating the electron transfer. And as a consequence of the substitution of Al in tetrahedral positions in SBA-15, Al-SBA-15 (10) gives the best result with 72% yield to vitamin K3. This catalyst markedly reduces the activation energy due to the modified activated center. Repeated experiments recommend that Al-SBA-15 is a steady and high-efficiency catalyst for the production of vitamin K3.
- Li, Fanfan,Liu, Guoji,Xu, Li,Yu, Yi,Zang, Zhouxuan
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- Different Solid Forms of Vitamin K3and Their Effect on the Chemical Stability
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MSB, the commercially available form of vitamin K3, has been widely applied in medicine, the nutrition industry, and livestock feed for decades. However, undesired degradation in an alkaline environment significantly decreases its efficacy and limits its application. Herein, polymorphism screening was performed on MSB to obtain solid forms with improved chemical stability. Two new solid forms were discovered, including form A and HB. Their crystal structures were elucidated by single crystal X-ray diffraction, and these forms were adequately characterized by powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and dynamic vapor sorption. The transformation relationships between these solid forms were fully discussed. Single-crystal-to-single-crystal transformation behavior was also detected by X-ray diffraction and hot-stage microscopy. The chemical stability in an alkaline environment of the newly discovered forms was investigated and compared with that of the marketed form. It was found that form A significantly alleviates the degradation of MSB. This gratifying chemical stability may be attributed to its compact packing pattern and the molecular conformation advantage.
- Yang, Zeen,Zhu, Bingqing,Jiang, Yuhang,Zhang, Zaiyong,Dai, Wenjuan,Mei, Xuefeng
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- Oxidation of 2-methyl-1-naphthol with H2O2 over mesoporous Ti-MMM-2 catalyst
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The catalytic oxidation of 2-methyl-1-naphthol (MNL) to 2-methyl-1,4-naphthoquinone (MNQ; menadione; vitamin K3) using aqueous H2O2 as an oxidant and hydrothermally stable mesoporous mesophase titanium silicates Ti-MMM-2 a
- Kholdeeva, Oxana A.,Zalomaeva, Olga V.,Shmakov, Alexander N.,Melgunov, Maxim S.,Sorokin, Alexander B.
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- Fabrication, characterization and structure activity relationship of Co and Mn encapsulated on magnetic nanocomposite and its application in one-pot tandem synthesis of various tetrazoles and vitamin K3
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Considering the importance of vitamin K3 in commercial pet foods, veterinary medicines, poultry, and some swine feed and also tetrazole derivatives in pharmacy, medicine, chemistry, petroleum, and military industry, design efficient catalytic systems are desirable. Herein, four magnetic nanocomposites (MNCs) of cobalt and manganese using metformin, 3-aminopropyltrimethoxysilane (L1) and 2-aminoethyl-3-aminopropyltrimethoxysilane (L2) were designed and constructed as an efficient and controllable catalytic system. The synthesized nanocomposites fully characterized by FT-IR, AAS, ICP-OES, BET, CHN elemental analysis, SEM, TEM, DLS, EDX, TGA, VSM, and XPS spectroscopy. The well-prepared magnetically recoverable nanocomposites were used in the synthesis of a wide derivatives of α-hydrazino tetrazoles (α-HyT), ferrocenyltetrazoles (FcT), arylaminotetrazoles (ArAT) and also vitamin K3. Besides, the effect of operating parameters, such as the amount of catalyst, nature of solvent, temperature and reaction time, metal nature, chain length and hydrophobicity properties of linkers, was studied in the catalytic efficiency of synthesized nanocatalysts. The best catalytic results were obtained in the following order: FS-L2-Met@Co(II) > FS-L2-Met@Mn(II) > FS-L1-Met@Co(II) > FS-L1-Met@Mn(II) due to their structural characteristics. In addition to high TOF, these magnetic nanocomposites are superior in easy, inexpensive, and commercially preparation, keeping the structural and magnetic characteristics, easy magnetically separation from the reaction medium, short reaction time, mild reaction condition, easy work-up, and reusability without any metal leaching in six runs. Graphical abstract: [Figure not available: see fulltext.]
- Ashouri, Fatemeh,Farahanipour, Alireza,Faraji, Ali Reza,Hekmatian, Zahra
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- Oxidative Dearomatization of Phenols and Polycyclic Aromatics with Hydrogen Peroxide Triggered by Heterogeneous Sulfonic Acids
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We report herein a method for the oxidative dearomatization of phenols and bare polycyclic arenes into the corresponding quinoid derivatives using hydrogen peroxide. The reaction is catalyzed by sulfonic acids and best results were achieved using heterogenized species. The best results using phenols were achieved using a hybrid material, namely a perfluorinated polymer functionalized with sulfonic acid groups supported on silica. The dearomatization of polycyclic aromatic hydrocarbons performed better using the polymeric acid catalyst. These methods operate under mild conditions, using mild and benign oxidants and thus minimizing the formation of waste.
- Pancrazzi, Francesco,Maestri, Giovanni,Maggi, Raimondo,Viscardi, Rosanna
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supporting information
p. 5407 - 5414
(2021/10/25)
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- Preparation method of photochemically synthesized 2-methyl-1, 4-naphthoquinone
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The invention discloses a preparation method of photochemically synthesized 2-methyl-1, 4-naphthoquinone. The preparation method specifically comprises the following steps: under the actions of a photosensitizer and an oxidant, carrying out photochemical reaction on 2-methyl naphthalene under the irradiation of LED light to prepare 2-methyl-1, 4-naphthoquinone. According to the preparation method,the photosensitizer is used, so that the use of a metal catalyst is avoided from the source; and the preparation method has the characteristics of water and air resistance, simplicity and conveniencein operation and post-treatment, environmental friendliness, high conversion rate and the like, and has better application value and potential economic and social benefits.
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Paragraph 0035-0043
(2021/02/13)
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- Discovery of juglone and its derivatives as potent SARS-CoV-2 main proteinase inhibitors
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SARS-CoV-2 as a positive-sense single-stranded RNA coronavirus caused the global outbreak of COVID-19. The main protease (Mpro) of the virus as the major enzyme processing viral polyproteins contributed to the replication and transcription of SARS-CoV-2 in host cells, and has been characterized as an attractive target in drug discovery. Herein, a set of 1,4-naphthoquinones with juglone skeleton were prepared and evaluated for the inhibitory efficacy against SARS-CoV-2 Mpro. More than half of the tested naphthoquinones could effectively inhibit the target enzyme with an inhibition rate of more than 90% at the concentration of 10 μM. In the structure-activity relationships (SARs) analysis, the characteristics of substituents and their position on juglone core scaffold were recognized as key ingredients for enzyme inhibitory activity. The most active compound, 2-acetyl-8-methoxy-1,4-naphthoquinone (15), which exhibited much higher potency in enzyme inhibitions than shikonin as the positive control, displayed an IC50 value of 72.07 ± 4.84 nM towards Mpro-mediated hydrolysis of the fluorescently labeled peptide. It fit well into the active site cavity of the enzyme by forming hydrogen bonds with adjacent amino acid residues in molecular docking studies. The results from in vitro antiviral activity evaluation demonstrated that the most potent Mpro inhibitor could significantly suppress the replication of SARS-CoV-2 in Vero E6 cells within the low micromolar concentrations, with its EC50 value of about 4.55 μM. It was non-toxic towards the host Vero E6 cells under tested concentrations. The present research work implied that juglone skeleton could be a primary template for the development of potent Mpro inhibitors.
- Cui, Jiahua,Jia, Jinping
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supporting information
(2021/08/25)
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- Menadione structure-based novel coronavirus 3CL protease inhibitor
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The invention discloses a menadione derivative capable of resisting novel coronavirus and medical application of the menadione derivative. The structure of the compound is shown as a formula (I), in the formula, R is a hydrogen atom, methyl, acetyl or hydroxyl, and R1 is hydrogen, methoxy, benzyloxy or benzoyloxy. The compound disclosed by the invention can inhibit the 3CL hydrolase of the 2019-nCoV novel coronavirus, and has the activity of resisting the novel coronavirus. In-vitro activity determination experiments show that the enzyme inhibition rate of part of the compounds reaches 90% or above under the concentration of 1 [mu] M, and is significantly superior to that of a positive control drug alkannin. Cell-level toxicity test experiment results show that the toxicity of menadione and the derivative thereof to host normal cells HSF is significantly lower than that of positive drugs alkannin and juglone, and part of the compounds show relatively strong anti-novel coronavirus activity in vitro, and have an important significance for the development of high-efficiency and low-toxicity new anti-novel coronavirus drugs.
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Paragraph 0028-0031
(2021/04/14)
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- Pd (II) complexes bearing “SNS” pincer-type thioether ligands: Application as catalysts in the synthesis of vitamin K3
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The novel four SNS pincer-type thioether containing Pd (II) complexes were synthesized and characterized by using FT-IR, UV-Vis, mass, elemental analysis techniques. The complexes were used as catalysts in the synthesis of vitamin K3 (2-methyl-1,4-naphthoquinone) from 2-methyl naphthalene. Hydrogen peroxide was used as green oxidant in acetic acid and sulfuric acid medium. L2-Pd (II) and L3-Pd (II) complexes showed the best catalytic activity with 62.63% and 61.05% selectivities in the conversions of 82.61% and 87.84%, respectively. Moreover, in silico studies on Pd (II) complexes have shown that L2-Pd (II) and L3-Pd (II) complexes have low band gaps between LUMO and HOMO energy levels and their electrostatic energy values are higher than other complex structures. This reveals that they have better chemical activity than other complexes and also supports the experimental studies carried out in this research. The conversions and the selectivities of these complexes are one of the best compared to the literature. Peroxyacetic acid with sulfuric acid is a very important oxidant in the oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphthoquinone.
- S?nmez, Mehmet,Sogukomerogullari, Hatice Gamze,Taskin Tok, Tugba,Uru?, Serhan
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- Method for preparing 2-methyl-1,4-naphthoquinone under supercritical conditions
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The invention discloses a method for preparing 2-methyl-1,4-naphthoquinone under supercritical conditions, wherein the method comprises the steps: in the presence of a catalytic amount of water, carrying out oxidation reaction on raw materials and oxygen in supercritical carbon dioxide to obtain the 2-methyl-1,4-naphthoquinone, wherein the raw material is one or a mixture of 2-methylnaphthohydroquinone, 2-methyl-5,6,7,8-tetrahydronaphthalene-1,4-diol, 2-methyl-5,8-dihydrogen-1,4-naphthalene diol. According to the method, the acid environment formed by supercritical carbon dioxide and trace water is used for catalytic reaction, the yield and purity of the obtained product are high, no pollution is caused to the environment, and operation is easy.
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Paragraph 0036-0041
(2021/02/06)
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- Preparation method of menadione sodium hydrogen sulfite
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The invention provides a preparation method of menadione sodium hydrogen sulfite. The preparation method comprises the following steps of: by taking alpha-methyl-gamma-butyrolactone and benzene as raw materials, preparing 2-methyl-3, 4-dihydro-1 (2H)-naphthalenone through Friedel-Crafts reaction; carrying out halogenation reaction on the 2-methyl-3, 4-dihydro-1 (2H)-naphthalenone and a halogenation reagent at the ortho position of carbonyl, and carrying out alkali elimination to prepare 2-methyl-1-naphthol; oxidizing the 2-methyl-1-naphthol through air to obtain 2-methyl-1, 4-naphthoquinone; and carrying out addition reaction on the 2-methyl-1, 4-naphthoquinone and sodium hydrogen sulfite to prepare the menadione sodium hydrogen sulfite. According to the method, the raw materials are cheap, easily available and low in cost; the process operation is safe, simple and convenient, less process wastewater is generated, and the method is green and environment-friendly; and the stability of the raw materials and intermediate products is high, high reaction activity and selectivity are high, reaction conditions are easy to realize, side reactions are few, the purity and yield of the product are high, and industrial production of the menadione sodium bisulfite can be facilitated.
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- Organophotocatalytic Aerobic Oxygenation of Phenols in a Visible-Light Continuous-Flow Photoreactor
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A mild photocatalytic phenol oxygenation enabled by a continuous-flow photoreactor using visible light and pressurized air is described herein. Products for wide-ranging applications, including the synthesis of vitamins, were obtained in high yields by precisely controlling principal process parameters. The reactor design permits low organophotocatalyst loadings to generate singlet oxygen. It is anticipated that the efficient aerobic phenol oxygenation to benzoquinones and p-quinols contributes to sustainable synthesis.
- Wellauer, Jo?l,Miladinov, Dragan,Buchholz, Thomas,Schütz, Jan,Stemmler, René T.,Medlock, Jonathan A.,Bonrath, Werner,Sparr, Christof
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supporting information
p. 9748 - 9752
(2021/05/27)
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- Green preparation method of menadione sodium bisulfite
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The invention provides a preparation method of menadione sodium bisulfite. The method comprises the following steps of: by using cheap and easily available 3, 4-dihydro-1 (2H)-naphthalenone as a raw material, carrying out halogenation-elimination to obtain 1-naphthol; carrying out methylation reaction to generate 2-methyl-1-naphthol; carrying out air oxidation on the 2-methyl-1-naphthol to obtain 2-methyl-1, 4-naphthoquinone; and carrying out addition reaction on the 2-methyl-1, 4-naphthoquinone and sodium hydrogen sulfite so as to obtain the menadione sodium bisulfite. The method has the advantages of cheap and easily available raw materials, low cost, safe, simple and convenient process operation, less process wastewater generation, green and environment-friendly performance, high stability of raw materials and intermediate products, high reaction activity and selectivity, easy realization of reaction conditions, few side reactions and high product purity and yield, and can facilitate the industrial production of the menadione sodium bisulfite.
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Page/Page column 0074-0077
(2021/07/31)
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- PHOTOOXIDATION OF PHENOLIC COMPOUNDS
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The present invention relates to the photooxidation of phenolic compounds to the respective quinoid compounds using methylene blue as photosensitizer in a solvent mixture of water and alcohols using light of the high wavelength range of the visible spectrum.
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Page/Page column 18
(2021/11/26)
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- Stereoselective [4+2] cycloaddition of singlet oxygen to naphthalenes controlled by carbohydrates
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Stereoselective reactions of singlet oxygen are of current interest. Since enantioselective photooxygenations have not been realized efficiently, auxiliary control is an attractive alternative. However, the obtained peroxides are often too labile for isolation or further transformations into enantiomerically pure products. Herein, we describe the oxidation of naphthalenes by singlet oxygen, where the face selectivity is controlled by carbohydrates for the first time. The synthesis of the precursors is easily achieved starting from naphthoquinone and a protected glucose derivative in only two steps. Photooxygenations proceed smoothly at low temperature, and we detected the corresponding endoperoxides as sole products by NMR. They are labile and can thermally react back to the parent naphthalenes and singlet oxygen. However, we could isolate and characterize two enantiomerically pure peroxides, which are sufficiently stable at room temperature. An interesting influence of substituents on the stereoselectivities of the photooxygenations has been found, ranging from 51:49 to up to 91:9 dr (diastereomeric ratio). We explain this by a hindered rotation of the carbohydrate substituents, substantiated by a combination of NOESY measurements and theoretical calculations. Finally, we could transfer the chiral information from a pure endoperoxide to an epoxide, which was isolated after cleavage of the sugar chiral auxiliary in enantiomerically pure form.
- Bauch, Marcel,Fudickar, Werner,Linker, Torsten
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- Selective catalytic synthesis of bio-based terephthalic acid from lignocellulose biomass
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_Efficient synthesis of bio-based chemicals from renewable lignocellulosic biomass is of great significance to promote the sustainable development of chemical industry. This work aims to demonstrate that terephthalic acid, a bulk high value chemical in petrochemical industry, can be synthesized using biomass. This novel controllable transformation process was started with the selective catalytic pyrolysis of sawdust biomass to form p-xylene intermediate. The high p-xylene yield of 23.4% was obtained using the Ga2O3/SiO2/HZSM-5 catalyst under the optimized reaction condition. Subsequently, the selective oxidation of the biomass-derived aromatic intermediates to terephthalic acid was realized with the metal oxide catalysts. The highest terephthalic acid yield of 72.8% with the terephthalic acid selectivity of 82.3% was achieved using the CoMn2O4@SiO2@Fe3O4 catalyst. Based on the study of the catalytic conversion of the model compounds and the catalyst characterizations, the reaction pathways and possible reaction mechanism have been proposed.
- Fan, Minghui,He, Yuting,Li, Quanxin,Luo, Yuehui,Yang, Mingyu,Zhang, Yanhua,Zhu, Lijuan
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- Formation of naphthoquinones and anthraquinones by carbonyl-hydroquinone/benzoquinone reactions: A potential route for the origin of 9,10-anthraquinone in tea
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The reaction of 2-alkenals (crotonaldehyde and 2-pentenal) with hydroquinones (hydroquinone and tert-butylhydroquinone) and benzoquinones (benzoquinone, methylbenzoquinone, and methoxybenzoquinone) was studied as a potential route for the endogenous formation of naphthoquinones and anthraquinones in foods. Polycyclic quinones were produced at a low water activity, within a wide pH range, and in the presence of air. 9,10-Anthraquinone formation had an activation energy of 46.1 ± 0.1 kJ·mol?1, and a reaction pathway for the formation of the different naphthoquinones and anthraquinones is proposed. These reactions also took place in tea, therefore suggesting that the common tea pollutant 9,10-anthraquinone is also a process-induced contaminant. In fact, when four commercial teas (from a total of eight studied teas) were heated at 60 °C for 72 h, they significantly (p 0.05) increased the amount of this toxicant. Reduction of 9,10-anthraquinone formation in teas is suggested to be carried out by reducing/scavenging its precursors.
- Zamora, Rosario,Hidalgo, Francisco J.
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- Catalytic performance of benzoxazine derived ordered mesoporous carbon materials for the selective oxidation of 2-methylnaphthalene
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2-Methylnaphthoquinone is an important chemical product. The catalyst used in the catalytic oxidation of 2-methylnaphthalene to 2-methylnaphthoquinone has been a research hotspot. In this paper, benzoxazine derived ordered mesoporous carbon materials were used as catalysts, and their catalytic performance in acetic acid/hydrogen peroxides was investigated. The N/S co-doped carbon material (NSCM) was prepared with thiourea-type benzoxazine as a carbon precursor and SBA-15 as a template. The nitrogen-doped carbon material (NCM) was prepared using the same method using aniline-type benzoxazine as a precursor. The carbon materials were characterized by N2 adsorption/desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results have shown that both carbon materials exhibit worm-like structure and have graphitized amorphous structure. Nitrogen in the carbon materials existed in the form of pyridine nitrogen and pyrrole nitrogen, which caused the surface defects of carbon materials. The surface defects are critical for the enhancement of the catalytic activity of carbon materials. With NSCM and NCM as catalysts, the yields of 2-methylnaphthoquinone were 78.8% and 65.7%, respectively. By comparison, NSCM has higher catalytic activity, and the catalytic activity remains stable after five cycles of use. These results indicate that NSCM has great potential as a highly efficient catalyst for the selective oxidation of 2-methylnaphthalene. This journal is
- Zang, Zhouxuan,Chang, Yingge,Yu, Yi,Zhang, Haihan,Xu, Li,Liu, Guoji
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p. 17422 - 17430
(2020/11/02)
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- Method for synthesizing 2-methyl-1, 4-naphthoquinone by catalyzing 2-methylnaphthalene
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The invention belongs to the field of production of 2-methyl-1, 4-naphthoquinone, and particularly relates to a method for preparing 2-methyl-1, 4-naphthoquinone through liquid-phase catalytic oxidation of 2-methylnaphthalene by using a titanium or aluminum-containing ordered mesoporous silicon molecular sieve as a catalyst. According to the present invention, good 2-naphthaldehyde conversion ratecan be achieved at a low temperature by adopting the catalyst, an obtained main product A is 2-methyl-1, 4-naphthoquinone, an obtained by-product B is 6-methyl-1, 4-naphthoquinone, and the yield of the main product 2-methyl-1, 4-naphthoquinone can achieve 72%. In addition, the preparation method is simple in process, and the catalyst can be recycled and is environment-friendly.
- -
-
Paragraph 0025-0047
(2020/03/09)
-
- Novel production process of 2-methyl-1, 4-naphthoquinone
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The invention relates to the technical field of fine chemical synthesis, in particular to a novel production process of 2-methyl-1, 4-naphthoquinone. The synthesis method comprises the following stepsof: 1, oxidizing o-cresol to synthesize o-methylbenzoquinone; 2, carrying out an addition reaction on the obtained o-methylbenzoquinone and butadiene to obtain 2-methyl-1, 4-tetrahydronaphthoquinone;and 3, taking the 2-methyl-1, 4-tetrahydronaphthoquinone, and oxidizing the 2-methyl-1, 4-tetrahydronaphthoquinone with DMSO under the action of a catalyst to obtain the 2-methyl-1, 4-naphthoquinone.According to the method, the 2-methyl-1, 4-naphthoquinone product is obtained through three-step reaction by taking o-cresol as an initial raw material, the reaction raw materials are easy to obtain,the operation is simple and convenient, the method is suitable for industrial production, the synthesis cost of vitamin K3 is reduced, and the productivity and the quality are improved. The problemsthat an existing 2-methyl-1, 4-naphthoquinone synthesis process is low in yield, a used catalyst is expensive, the production cost is high, many byproducts are produced, and heavy metal ion pollutioncannot be fundamentally avoided when an inorganic salt oxidizing agent or a metal-containing catalyst is applied are solved.
- -
-
Paragraph 0020; 0024; 0026; 0027; 0029; 0030; 0032
(2020/10/04)
-
- Bisketene Equivalents as Diels-Alder Dienes
-
2,5-Bis(tert-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents for application as dienes in the Diels-Alder reaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted para-hydroquinones in unprotected form via a one-pot Diels-Alder/ring-opening/tautomerization sequence. The synthesis of para-benzoquinones from acetylenic dienophiles, including benzynes, is also demonstrated, and 2,5-bis(tert-butyldimethylsilyloxy)pyrroles are established as competent dienes for the synthesis of para-iminoquinones. Application in natural product synthesis enables gram-scale access to the neuroprotective agent (±)-indanostatin.
- Dissanayake, Isuru,Hart, Jacob D.,Becroft, Emma C.,Sumby, Christopher J.,Newton, Christopher G.
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supporting information
p. 13328 - 13333
(2020/09/03)
-
- Synthesis and characterization of a novel ruthenium(ii) trisbipyridine complex magnetic nanocomposite for the selective oxidation of phenols
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Anchoring ruthenium(ii) trisbipyridine complex [Ru(Bpy)3]2+ into a magnetic dendritic fibrous silica nanostructure produces an unprecedented strong nanocatalyst, FeNi3/DFNS/[Ru(Bpy)3]2+. Impressive oxidation of phenols to 1,4-benzoquinones catalyzed by FeNi3/DFNS/[Ru(Bpy)3]2+ is obtained in acetonitrile and water solution with molecular dioxygen as oxidant. Exclusively, apparently inert phenols such as phenol itself and mono-alkyl-substituted phenols are impressively oxidized to produce 1,4-benzoquinones through activation of the C-H bond in the position para to the carbon-oxygen bond under mild conditions. In addition, the production of industrially significant quinones that are known intermediates for vitamin combinations is investigated and studied FeNi3/DFNS/[Ru(Bpy)3]2+ magnetic nanoparticles were produced, and their properties were investigated by AFM, FTIR, XRD, TGA, SEM, TEM, and VSM.
- Fei, Zhengxin,Chen, Feng,Zhong, Mingqiang,Qiu, Jianping,Li, Weidong,Sadeghzadeh, Seyed Mohsen
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p. 28078 - 28088
(2019/09/30)
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- Synthetic method for 2-methyl-1,4-naphthoquinone
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The invention provides a synthetic method for 2-methyl-1,4-naphthoquinone. The synthetic method takes hydrogen peroxide and 2-methyl-1-naphthol as main raw materials, and performs oxidation reaction in the presence of a solvent and catalyst sulfuric acid, so that 2-methyl-1,4-naphthoquinone can be obtained through preparation. The synthetic method is simple, green, safe, environmentally friendly,high in yield and selectivity, low in cost and suitable for industrial production, and the discharging of waste water without heavy metals can be achieved.
- -
-
Paragraph 0025; 0042-0054
(2019/03/15)
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- Bismuth-catalyzed methylation and alkylation of quinone derivatives with tert-butyl peroxybenzoate as an oxidant
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A bismuth-catalyzed methylation of quinones in the presence of tert-butyl peroxybenzoate (TBPB) was developed via a radical reaction mechanism. Particularly, TBPB was used not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the alkylation of quinones. This reaction tolerated a series of functional groups and prepared a series of derivatives of vitamin K3 and benzoquinone. Notably, antimalarial parvaquone was synthesized by the reaction.
- Yang, Jian,Dong, Yu,He, Shuai,Shi, Zhi-Chuan,Wang, Yu,Wang, Ji-Yu
-
-
- Role of the Ring Methyl Groups in 2′,3′-Benzoabscisic Acid Analogues
-
Five analogues of iso-PhABA (20) developed earlier by our research group were designed and synthesized. The bioassay results show that the number and position of methyl groups along with the substitution of hydrogen atoms of the methyl group have a great influence on the activity. Compared with iso-PhABA, the inhibitory activity of diMe-PhABA (21) on seed germination and rice seedling growth decreased slightly; however, it significantly reduced the capability of inhibiting wheat embryo germination. Both 3′-deMe-iso-PhABA (22) and 2′-deMe-PhABA (23) exhibited weak inhibitory activities, and 11′-methoxy iso-PhABA (24a/24b) was much more efficient than its isomer 24c/24d in all bioassays. These results reveal the preservation of quaternary carbon at the 2′ or 3′ position is necessary to maintain its ABA-like biological activity, and demethylation at the 3′ position has a more significant effect. The selectivity of these compounds to different physiological processes makes them available as selective probes for different ABA receptors.
- Wan, Chuan,Hong, Qilin,Zhang, Xueqin,Zeng, Yuejuan,Yang, Dongyan,Che, Chuanliang,Ding, Shanshan,Xiao, Yumei,Li, Jia-Qi,Qin, Zhaohai
-
-
- Role of the Ring Methyl Groups in 2′,3′-Benzoabscisic Acid Analogues
-
Five analogues of iso-PhABA (20) developed earlier by our research group were designed and synthesized. The bioassay results show that the number and position of methyl groups along with the substitution of hydrogen atoms of the methyl group have a great influence on the activity. Compared with iso-PhABA, the inhibitory activity of diMe-PhABA (21) on seed germination and rice seedling growth decreased slightly; however, it significantly reduced the capability of inhibiting wheat embryo germination. Both 3′-deMe-iso-PhABA (22) and 2′-deMe-PhABA (23) exhibited weak inhibitory activities, and 11′-methoxy iso-PhABA (24a/24b) was much more efficient than its isomer 24c/24d in all bioassays. These results reveal the preservation of quaternary carbon at the 2′ or 3′ position is necessary to maintain its ABA-like biological activity, and demethylation at the 3′ position has a more significant effect. The selectivity of these compounds to different physiological processes makes them available as selective probes for different ABA receptors.
- Wan, Chuan,Hong, Qilin,Zhang, Xueqin,Zeng, Yuejuan,Yang, Dongyan,Che, Chuanliang,Ding, Shanshan,Xiao, Yumei,Li, Jia-Qi,Qin, Zhaohai
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p. 4995 - 5007
(2019/05/08)
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- Activated Carbon-Promoted Dehydrogenation of Hydroquinones to Benzoquinones, Naphthoquinones, and Anthraquinones under Molecular Oxygen Atmosphere
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We found that the activated carbon-molecular oxygen system promotes the conversion of hydroquinones to benzoquinones, naphthoquinones, and anthraquinones, which are often found in natural products and pharmaceuticals. In particular, the one-pot synthesis of naphthoquinones and anthraquinones involving a Diels-Alder reaction is a useful protocol for this purpose.
- Kim, Sanghun,Matsubara, Ryosuke,Hayashi, Masahiko
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p. 2997 - 3003
(2019/03/08)
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- Preparation method for 2-methyl-1,4-naphthoquinone
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The invention relates to a preparation method for 2-methyl-1,4-naphthoquinone. The preparation method utilizes phthalic acid diester and 3-cyanobutyrate to prepare 2-methyl-1,4-naphthoquinone throughcondensation, hydrolysis and decarboxylation and hydrogen cyanide removal under the action of strong alkali. The preparation method is easy in raw material obtaining, cheap in price and high in reaction atomic economy; and the 3-cyanobutyrate can be obtained through addition reaction of by-product hydrogen cyanide and 2-crotonate; and the preparation method is easy to operate, less in waste wateramount and green and environmentally friendly in technology, and therefore the discharging of waste water without heavy metals can be realized, and industrial production can be achieved.
- -
-
Paragraph 0046-0050; 0053
(2019/03/15)
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- Mesitylene biaryl (triazine) tricarboxylic acid copper complex containing nitrogen oxygen radicals, and application thereof in preparing menadione
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The invention belongs to the field of organic synthesis, and particularly relates to a mesitylene biaryl (triazine) tricarboxylic acid copper complex containing nitrogen oxygen radicals, and application thereof in preparing menadione. The mesitylene biaryl (triazine) tricarboxylic acid copper complex containing the nitrogen oxygen radicals has the structural formula as shown in the formula I, wherein X is C or N; R1 is -H, -CH3, -C2H5 or -OCH3 and can be at any position on an aromatic ring; R2 and R3 are -H, -CH3 or Cl, and can be the same or different. The complex is novel in structure, can be used as a stable heterogeneous copper catalyst with high activity, is capable of high-efficiently catalyzing and oxidizing methylnaphthalene so as to synthesize the menadione, can be free of using chromic acid, hydrogen peroxide and other strong oxidants, and is mild in reaction conditions, high in yield, recyclable, economic and high-efficiency in reaction, and broad in application prospect.
- -
-
Paragraph 0136; 0139; 0141; 0143; 0145; 0147; 0152-0153
(2019/01/14)
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- Synthesizing method of beta-menadione
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The invention relates to a synthesizing method of beta-menadione. The synthesizing method comprises the following steps of respectively dissolving a certain amount of beta-methylnaphthalene and metachloroperbenzoic acid into a proper amount of chloroform; performing ultrasonic reaction for a period of time at certain temperature; filtering reaction liquid, washing by saturated NaHCO3 solution and water, and drying by anhydrous Na2SO4; performing reduced pressure distillation to obtain the product of beta-menadione. The synthesizing method has the advantages that the conversion rate of the beta-menadione is 80%; the yield of the beta-menadione is 36%; the reaction time is short, the condition is mild, the product is easily separated, and the like; any catalyst is not used in reaction, and the energy consumption and pollution to environment are decreased.
- -
-
Paragraph 0010-0013
(2017/08/30)
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- Electrochemical synthesis of quinones and other derivatives in biphasic medium
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Electrochemical synthesis of quinones has been attempted from phenols, 1,4-dihydroxybenzenes, 1,4-dihydroxynaphthalenes and related compounds using biphasic media. Excellent yields of quinones (98%) or brominated diols have been achieved with good current efficiency. Reuse of the electrolyte without any modification and quantitative conversion of substrate with theoretical amount of current are the advantages of this method.
- Shanmugam,Kulangiappar,Ramaprakash,Vasudevan,Senthil Kumar,Velayutham,Raju
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p. 2294 - 2297
(2017/05/19)
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- Method for preparing 2-methyl-1,4-naphthoquinone through microwave radiation
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The invention relates to a method for preparing 2-methyl-1,4-naphthoquinone through microwave radiation. The 2-methyl-1,4-naphthoquinone is prepared from beta-methylnaphthalene in a solvent acetate acid gracial under the action of microwave radiation with a polystyrene type polymeric peroxy acid as an oxidant, and the yield reaches 65.0% or above. Microwave radiation heating is adopted, so the reaction time is obviously shortened, and the product yield is improved; and the polymeric peroxy acid oxidant is adopted, so the method has the advantages of high product yield, convenient post-treatment , avoiding of heavy metal pollution of chromium salt oxidants, environmental protection, and important application values.
- -
-
Paragraph 0036; 0041; 0042
(2017/06/24)
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- A kind of ultrasonic promote the production method of β-menadione
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The invention discloses a method for promoting beta-menadione production through ultrasonic waves. The method includes the steps that oxidation liquid is prepared from sodium bichromate and sulfuric acid, the oxidization liquid is slowly added into mixed mediums containing beta-methyl naphthalene, phase transfer catalysts and water to undergo reaction, and the ultrasonic waves act on the reaction system in the reacting process. Due to the fact that the ultrasonic waves have the promotion effect on the reaction, the temperature of the reaction system can be greatly lowered, side reactions are reduced, the product yield is improved, and the using amount of the oxidization liquid can be greatly reduced.
- -
-
Paragraph 0040-0041
(2017/02/23)
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- A vitamin K 3 method and apparatus for the preparation of
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The invention provides a method and a device for preparing vitamin K3. The method comprises the following steps of mixing and cooling a beta-methylnaphthalene flow, an oxide aqueous solution flow and a circulation flow to form a reaction liquid flow, continuously carrying out the cooling reaction for the reaction liquid flow to form a crude product flow, and separating vitamin K3 from the crude product flow; and returning a part of the crude product flow as the circulation flow to the reaction liquid flow, wherein the oxide aqueous solution flow comprises sodium dichromate and sulfuric acid, the content of CrO3 (chromium trioxide) is 200 to 350g/L, the content of the sulfuric acid is 400 to 550g/L, the flow rate ratio of the oxide aqueous solution and the beta-methylnaphthalene flow is (7-11): 1, and the flow rate ratio of the beta-methylnaphthalene flow and the reaction liquid flow is 1: (900-1300); and the temperature is controlled at 55 to 65 DEG C in cooling reaction. The device comprises a mixing tank, a tube nest reaction tank, a separation purifying part, a temperature control part and a flow rate control part. By adopting the method and the device, the problem that the conversion rate is influenced due to the difficulty in controlling the oxidization process of the existing process for preparing vitamin K3 from beta-methylnaphthalene can be solved.
- -
-
Paragraph 0035; 0036; 0037; 0038; 0039; 0040; 0041; 0042
(2016/10/07)
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- Exploiting photooxygenations mediated by porphyrinoid photocatalysts under continuous flow conditions
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Photooxygenation reactions are a powerful synthetic tool to produce oxidized organic compounds; however, these reactions often exhibit experimental limitations including the production of complex mixtures that hinder desired product isolation and scale-up. Herein, we present a photocatalysed protocol under continuous flow conditions using a simple home built photoreactor and porphyrinoids as photocatalysts. Reaction conditions, long-term experiments, and scope demonstrate a protocol that is cost-effective, safe, reproducible and robust, thus allowing the production of relevant substituted naphthoquinones with interest in natural product synthesis and biological activity.
- De Oliveira, Kleber T.,Miller, L. Zane,McQuade, D. Tyler
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p. 12717 - 12725
(2016/02/12)
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- Intramolecular carbonyl-ene reactions in the synthesis of peri-oxygenated hydroaromatics
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2-Methallyl aromatic aldehydes, synthesized by Suzuki coupling of 2-formylphenylboronic acids, are shown to provide cycloalkylidene ene products under acidic conditions. Susceptibility of the products to aromatization is manoeuvred by varying the reaction conditions and catalysts including binol-derived Br?nsted acid catalysts. A peri-effect is identified as a controlling factor for the aromatizations. Several oxidative transformations of an ene product are carried out as model studies of hydroaromatic polyketide natural products.
- Basak, Shyam,Mal, Dipakranjan
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p. 1758 - 1772
(2018/03/29)
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- Solvent and Temperature Effects on the Platinum-Catalyzed Oxidative Coupling of 1-Naphthols
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Using H2O2 as the oxidant, 1-naphthols with electron-donating groups at the 2- and 4-positions couple oxidatively over a carbon-supported platinum catalyst to 3,3′-substituted 1,1′-binaphthalenylidene-4,4′-diones and 4,4′-substituted 2,2′-binaphthalenylidene-1,1′-diones, respectively. The binaphthalenyl diols are the intermediates. The selectivity to individual products is influenced by the reaction temperature (room temp. or reflux) and by the solvent used. Under reflux, complete conversions are obtained within 40 min. At room temp. high diol yields can be obtained, e.g. 96 % from 2-methyl-1-naphthol in MeOH. Under reflux the reaction proceeds always further to the diones (at least to some extent), and THF is a promising solvent for the selective one-pot two-step oxidation of 1-naphthols to the diones (e.g. 81 % from 4-methoxy-1-naphthol). In most other solvents (reflux) naphthoquinones are observed as byproducts. In an attempt to optimize the yield of menadione, 30.5 % was obtained in boiling MeNO2.
- Maphoru, Mabuatsela V.,Heveling, Josef,Kesavan Pillai, Sreejarani
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p. 331 - 337
(2016/02/14)
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- PPh3·HBr-DMSO: A Reagent System for Diverse Chemoselective Transformations
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The broad applicability of the hitherto unexplored reagent combination PPh3·HBr-DMSO is exemplified with multiple highly diverse one-step transformations to synthetically useful building blocks, such as flavones, 4H-thiochromen-4-ones, α-hydroxy ketones, 1,4-naphthoquinones (including vitamin K3), 2-bromo-3-substituted-1H-1-indenones, 2-methylthio-1H-1-indenones, 3-butyne-1,2-dione, and 4-pentene-2,3-diones. The simple and mild reaction conditions make the reagent superior in terms of yield and substrate scope in comparison with the existing alternatives.
- Mal, Kanchan,Kaur, Amanpreet,Haque, Fazle,Das, Indrajit
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p. 6400 - 6410
(2015/06/30)
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- Efficient Metal-Free Catalytic Reaction Pathway for Selective Oxidation of Substituted Phenols
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Selective oxidation of substituted phenols to p-benzoquinones is known to be inefficient because of the competing C-O coupling reaction caused by phenoxy radicals. The poor stability of conventional metal-based catalysts represents another bottleneck for industrial application. Here, we describe a metal-free reaction pathway in which onion-like carbon (OLC) as a low-cost catalyst exhibits excellent catalytic activity and stability in the selective oxidation of mono-, di- and trisubstituted phenols to their corresponding p-benzoquinones, even better than the reported metal-based catalysts (e.g., yield, stability) and industrial catalysts for particular substrates. Together with XPS, Raman, DFT calculations, and a series of comparative experiments, we demonstrate that the zigzag configuration as a type of carbon defects may play a crucial role in these reactions by stabilizing the intermediate phenoxy radicals.
- Lin, Yangming,Li, Bo,Feng, Zhenbao,Kim, Yoong Ahm,Endo, Morinobu,Su, Dang Sheng
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p. 5921 - 5926
(2015/10/12)
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- Mesostructured vanadia-alumina catalysts for the synthesis of vitamin K3
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Liquid-phase selective oxidation of 2-methylnaphtalene to the vitamin K3 was investigated on a series of mesostructured vanadia-alumina catalysts with different V/Al ratios (0.1-1). They were prepared by the co-precipitation of ammonium metavanadate and aluminum nitrate at pH 5 and characterized by XRD, Raman, TG-DTA, elemental analysis and adsorption-desorption isotherms of nitrogen at -196 °C. The influence of the catalyst composition and calcination temperature upon the physico-chemical properties were closely investigated in relation with the catalytic performances. The result of this investigation indicated the catalysts containing a higher vanadium loading and calcined at 300 °C as the most active. Thus, the VAl07 catalyst led to a selectivity in vitamin K3 of 54% for a conversion of 2-methylnaphtalene of 76%. Such an activity corresponded to mixtures where metavanadate (Raman line at 940 cm-1) and decavanadate (Raman line at 990 cm-1) species were the most abundant. No lines of V2O5 (around 705 cm-1) were detected in the catalysts calcined below 600 °C.
- Florea,Marin,P?l??anu,Nea?u,Parvulescu
-
-
- Selective oxidation of pseudocumene and 2-methylnaphthalene with aqueous hydrogen peroxide catalyzed by γ-Keggin divanadium-substituted polyoxotungstate
-
The catalytic performance of a γ-Keggin divanadium-substituted phosphotungstate, (Bu4N)4[γ-PW10O38V2(μ-O)(μ-OH)], has been evaluated in the selective oxidation of 1,2,4-trimethylbenzene (pseudocumene, PC) and 2-methylnaphthalene with the green oxidant, 35% aqueous hydrogen peroxide. Under conditions of H2O2 deficiency ([PC]/[H2O2] = 17-22), PC oxidation proceeded with unusually high chemo- and regioselectivity, producing exclusively 2,4,5-trimethylphenol (2,4,5-TMP) and 2,3,5-TMP in a molar ratio of 7.3/1 and a yield of 73% based on the oxidant. Isomeric 2,3,6-trimethylphenol was found in trace amounts. Under conditions of H2O2 excess ([H2O2]/[PC] = 8), 2,3,5-trimethyl-1,4-benzoquinone (TMBQ, vitamin E key intermediate) formed with 41% selectivity at 41% substrate conversion. Atypical regioselectivity was also found in the oxidation of 2-methylnaphthalene which gave predominantly 6-methyl-1,4-naphthoquinone (6-MNQ) rather than isomeric 2-MNQ. The ratio between the isomers could be altered by varying the catalyst and oxidant amounts.
- Zalomaeva, Olga V.,Evtushok, Vasiliy Yu.,Maksimov, Gennadii M.,Kholdeeva, Oxana A.
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p. 210 - 216
(2015/09/01)
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- Synthesis of Vitamin K and Related Naphthoquinones via Demethoxycarbonylative Annulations and a Retro-Wittig Rearrangement
-
Anionic annulations of 3-nucleofugal phthalides with α-alkyl(aryl)acrylates involving a demethoxycarbonylation provide a succinct synthesis of vitamin K and related naphthoquinones. Also reported is a new cascade reaction stemming from a Cope-retro-Wittig rearrangement. This cascade leads to direct formation of 1-hydroxy-4-prenyloxynaphthalene-2-carboxylates from the corresponding α-prenyl acrylate acceptors.
- Mal, Dipakranjan,Ghosh, Ketaki,Jana, Supriti
-
supporting information
p. 5800 - 5803
(2015/12/11)
-
- Tetracycline analogues with a selective inhibitory effect on HIF-1α
-
As part of a programme to discover novel transcription factor inhibitors, a 40-membered library of tetracycline analogues was screened to identify potential HIF-1 inhibitors. Two novel analogues (5b and 5c) with significant HIF-1 modulation properties were identified. These molecules possess good cellular penetration properties, and provide significant down-regulation of VEGF in U251 cells.
- Bendiabdellah,Rahman,Uranchimeg,Nahar,Antonow,Shoemaker,Melillo,Zinzalla,Thurston
-
supporting information
p. 923 - 926
(2014/07/08)
-
- Highly selective oxidation of alkylphenols to p-benzoquinones with aqueous hydrogen peroxide catalyzed by divanadium-substituted polyoxotungstates
-
The catalytic performance of divanadium- and dititanium-substituted γ-Keggin polyoxotungstates, TBA4H[γ-PW10V 2O40] (I, TBA = tetra-n-butylammonium), TBA 4H2[γ-SiW10V2O40] (II), and TBA8[{γ-SiW10Ti2O 36(OH)2}2(μ-O)2] (III) has been assessed in the selective oxidation of industrially important alkylphenols/naphthols with the green oxidant 35% aqueous H2O 2. Phosphotungstate I revealed a superior catalytic performance in terms of activity and selectivity and produced alkylsubstituted p-benzo- and naphthoquinones with good to excellent yields. By applying the optimized reaction conditions, 2,3,5-trimethyl-p-benzoquinone (TMBQ, vitamin E key intermediate) was obtained in a nearly quantitative yield via oxidation of 2,3,6-trimethylphenol (TMP). The efficiency of H2O2 utilization reached 90%. The catalyst retained its structure under turnover conditions and could be recycled and reused. An active peroxo vanadium complex responsible for the oxidation of TMP to TMBQ has been identified using 51V and 31P NMR spectroscopy.
- Ivanchikova, Irina D.,Maksimchuk, Nataliya V.,Maksimovskaya, Raisa I.,Maksimov, Gennadii M.,Kholdeeva, Oxana A.
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p. 2706 - 2713
(2014/08/18)
-
- Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer: A highly efficient catalyst for biomimetic oxygenation reactions
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Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer complex was prepared by the reaction of bis(perfluorophenyl)maleonitrile and Fe(CO)5and tested in catalytic oxygenation reactions of several hydrocarbons in comparison with the analogous non-fluorinated phthalocyanine complexes. Results of the study demonstrate that this complex is a highly efficient catalyst for the oxygenation of anthracene, 2-tert-butylanthracene, naphthalene, 2-methylnaphthalene, phenanthrene, adamantane, and toluene using iodosylbenzene, oligomeric iodosylbenzene sulfate, or Oxone as stoichiometric oxidants.
- Yusubov, Mekhman S.,Celik, Cumali,Geraskina, Margarita R.,Yoshimura, Akira,Zhdankin, Viktor V.,Nemykin, Victor N.
-
supporting information
p. 5687 - 5690
(2014/12/11)
-
- Synthesis of aryl- and alkylquinones through rhodium-catalyzed C-C coupling under mild conditions
-
A direct arylation, alkylation of quinones with aryl and alkyl boronic acids through rhodium-catalyzed C-C coupling has been developed under mild conditions. [CpRhCl2]2 was shown to be the most effective catalyst for the transformation. More importantly, good to excellent yields were obtained under room temperature and base-free conditions. This reaction provides a practical, efficient method for the synthesis of aryl- and alkylquinones.
- Wang, Dawei,Ge, Bingyang,Du, Liyong,Miao, Hongyan,Ding, Yuqiang
-
supporting information
p. 2895 - 2898
(2015/02/02)
-
- Asymmetric hydroxylative phenol dearomatization promoted by chiral binaphthylic and biphenylic iodanes
-
The long-standing quest for chiral hypervalent organoiodine compounds (i.e., iodanes) as metal-free reagents for asymmetric synthesis continues. Although remarkable progress has recently been made in organoiodine-catalyzed reactions using a terminal oxidant in stoichiometric amounts, there is still a significant need for "flaskable" chiral iodane reagents. Herein, we describe the synthesis of new iodobinaphthyls and iodobiphenyls, their successful and selective DMDO-mediated oxidation into either λ3- or λ5-iodanes, and the evaluation of their capacity to promote asymmetric hydroxylative phenol dearomatization (HPD) reactions. Most notably, a C2-symmetrical biphenylic λ5-iodane promoted the HPD-induced conversion of the monoterpene thymol into the corresponding ortho-quinol-based [4+2] cyclodimer (i.e., bis(thymol)) with enantiomeric excesses of up to 94 %.
- Bosset, Cyril,Coffinier, Romain,Peixoto, Philippe A.,El Assal, Mourad,Pouysegu, Laurent,Quideau, Stephane,Miqueu, Karinne,Sotiropoulos, Jean-Marc
-
supporting information
p. 9860 - 9864,5
(2014/10/15)
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- Process for Industrial Production of 2-Methyl-1,4-Naphthaquinone
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The present invention describes a process for producing 2-methyl-1,4-naphthoquinone by oxidizing 2-methylnaphthalene with fresh hydrogen peroxide in the presence of glacial acetic acid without any mineral or transition metal catalyst.
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Page/Page column 2
(2014/01/07)
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