58-27-5Relevant articles and documents
A new metal-free access to vitamin K3
Bohle, Anne,Schubert, Anett,Sun, Yu,Thiel, Werner R.
, p. 1011 - 1015 (2006)
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.
An Experimental Test of the Competition Correction for Charge Capture from the Matrix in Intermolecular Electron Tunnelling Reactions
Huddleston, R. Kurt,Miller, John R.
, p. 4867 - 4872 (1983)
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.
Selective synthesis of vitamin K3 over mesoporous NbSBA-15 catalysts synthesized by an efficient hydrothermal method
Selvaraj,Park,Kim,Kawi,Ha
, p. 9633 - 9638 (2012)
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.
Manganese(II) naphthenate as effective catalyst for the clean oxidation of 2-methylnaphthalene by hydrogen peroxide
Yan, Tingfeng,Hong, Mei,Niu, Lei,Jiang, Feng,Xiao, Guomin
, p. 1839 - 1846 (2012)
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.
OXIDATION OF 2-METHYLNAPHTHALENE TO 2-METHYL-1,4-NAPHTHOQUINONE WITH HYDROGEN PEROXIDE IN THE PRESENCE OF Pd(II)-POLYSTYRENE SULFONIC ACID RESIN
Yamaguchi, Satoru,Inoue, Masami,Enomoto, Saburo
, p. 827 - 828 (1985)
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.
Phase-transfer oxidation of 2-methyl-1-naphthol into 2-methyl-1,4-naphthoquinone in the presence of vanadomolybdophosphoric heteropolyacids
Matveev, K. I.,Zhizhina, E. G.,Odyakov, V. F.,Parmon, V. N.
, p. 1142 - 1145 (1994)
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Liquid phase oxidation of 2-methylnaphthalene to 2-methyl-1,4- naphthoquinone over lanthanum doped MCM-41
Zi, Guoli,Chen, Daomei,Li, Bin,Li, Zhiqiang,Luo, Xia,Zhang, Jinping,Li, Lin,Wang, Jiaqiang
, p. 10 - 14 (2014)
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.
Metalloporphyrin-catalyzed oxidation of 2-methylnaphthalene to vitamin K3 and 6-methyl-1,4-naphthoquinone by potassium monopersulfate in aqueous solution
Song, Rita,Sorokin, Alexander,Bernadou, Jean,Meunier, Bernard
, p. 673 - 678 (1997)
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).
Different Solid Forms of Vitamin K3and Their Effect on the Chemical Stability
Yang, Zeen,Zhu, Bingqing,Jiang, Yuhang,Zhang, Zaiyong,Dai, Wenjuan,Mei, Xuefeng
, p. 528 - 535 (2021)
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.
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
Ashouri, Fatemeh,Farahanipour, Alireza,Faraji, Ali Reza,Hekmatian, Zahra
, (2022/02/21)
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.]
Oxidative Dearomatization of Phenols and Polycyclic Aromatics with Hydrogen Peroxide Triggered by Heterogeneous Sulfonic Acids
Pancrazzi, Francesco,Maestri, Giovanni,Maggi, Raimondo,Viscardi, Rosanna
supporting information, p. 5407 - 5414 (2021/10/25)
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.
Discovery of juglone and its derivatives as potent SARS-CoV-2 main proteinase inhibitors
Cui, Jiahua,Jia, Jinping
supporting information, (2021/08/25)
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.