- Tunability in polyatomic molecule diffusion through tunneling versus pacing
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The diffusion temperature of molecular 'walkers', molecules that are capable of moving unidirectionally across a substrate violating its symmetry, can be tuned over a wide range utilizing extension of their aromatic backbone, insertion of a second set of substrate linkers (converting bipedal into quadrupedal species), and substitution on the ring. Density functional theory simulation of the molecular dynamics identifies the motion of the quadrupedal species as pacing (as opposed to trotting or gliding). Knowledge about the diffusion mode allows us to draw conclusions on the relevance of tunneling to the surface diffusion of polyatomic organic molecules.
- Cheng, Zhihai,Chu, Eric S.,Sun, Dezheng,Kim, Daeho,Zhu, Yeming,Luo, Miaomiao,Pawin, Greg,Wong, Kin L.,Kwon, Ki-Young,Carp, Robert,Marsella, Michael,Bartels, Ludwig
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Read Online
- Anodic oxidation of methylnaphthalenes and 9-methylanthracene
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Anodic methoxylation of a series of methylnaphthalenes (1-methylnaphthalene, 2-methylnaphtholene, 1,3-dimethylnaphthalene, 1,4-dimethylnaphthalene, 1,5-dimethylnaphthalene, 2,6-dimethylnaphthalene, 2,3,5-trimethylnaphthalene) and 9-methylanthracene afforded a series of nuclear-addition products. The process of nuclear addition is only observed in an aromatic ring and no chain methoxylated products were obtained. A probable mechanism is provided.
- Barba, Isidoro,Tornero, Marcial
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Read Online
- Efficient Multigram-Scale Synthesis of 7-Substituted 3-Methyltetral-1-ones and 6-Fluoromenadione
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Herein, we report a safe and economical multigram synthesis of 6-fluoromenadione, an intermediate in the synthesis of novel biologically active agents. The key to this six-step sequence process involves the condensation of the readily available starting 4′-fluoropropiophenone and glyoxylic acid, a bromination-elimination sequence from 7-fluoro-3-methyltetral-1-one allowing aromatization of the naphthol intermediate, which is then oxidized into the corresponding 6-fluoromenadione. The multigram process has been demonstrated from 25 g of starting material scale with an improved overall yield of 50% and then applied to five other 7-substituted 3-methyltetralones and their corresponding 6-substituted menadiones.
- Davioud-Charvet, Elisabeth,Roignant, Matthieu,Trometer, Nathan
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- A Platform of Regioselective Methodologies to Access Polysubstituted 2-Methyl-1,4-naphthoquinone Derivatives: Scope and Limitations
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A platform of synthetic methodologies has been established to access a focused library of polysubstituted 3-benzylmenadione derivatives functionalized on the aromatic ring of the naphthoquinone core. Two main routes were explored: 1) The naphthol route, starting from either an α-tetralone or a propiophenone, and 2) the regioselective Diels-Alder reaction, starting from various dienes and two 2-bromo-5(or 6)-methyl-1,4-benzoquinones. 6-Substituted 2-methylnaphthols were synthesized by using a xanthate-mediated free-radical addition/cyclization sequence for the construction of the 6-substituted menadione subunit. Furthermore, an efficient and simple new pathway that allows the formation of 6- or 7-substituted 3-(substituted-benzyl)menadione regioisomers from a common commercial scaffold has also been developed by the naphthol route, advantageous with regard to step economy. Our synthetic methodologies exemplified by 34 compounds have allowed structure-activity relationships to be deduced for use as the basis for the development of new antimalarial redox-active polysubstituted benzylmenadione derivatives.
- Rodo, Elena Cesar,Feng, Liwen,Jida, Mouhamad,Ehrhardt, Katharina,Bielitza, Max,Boilevin, Jérémy,Lanzer, Michael,Williams, David Lee,Lanfranchi, Don Antoine,Davioud-Charvet, Elisabeth
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p. 1982 - 1993
(2016/04/26)
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- Copper-mediated oxidative trifluoromethylthiolation of quinones
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A novel copper-mediated oxidative trifluoromethylthiolation of quinones was developed. This protocol provided an efficient and practical approach to a series of trifluoromethylthiolated quinones.
- Li, Chao,Zhang, Ke,Xu, Xiu-Hua,Qing, Feng-Ling
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supporting information
p. 6273 - 6275
(2015/10/20)
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- TOTAL SYNTHESIS OF REDOX-ACTIVE 1.4-NAPHTHOQUINONES AND THEIR METABOLITES AND THEIR THERAPEUTIC USE AS ANTIMALARIAL AND SCHISTOMICIDAL AGENTS
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Naphthoquinones, azanaphthoquinones and benxanthones, their process of synthesis and their use as antimalarial or antischistosomal agents.
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Page/Page column 74
(2012/10/18)
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- Total synthesis of redox-active 1.4-naphthoquinones and their metabolites and their therapeutic use as antimalarial and schistomicidal agents
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Naphthoquinones, azanaphthoquinones and benxanthones, their process of synthesis and their use as antimalarial or antischistosomal agents.
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Paragraph 0098-0101
(2013/03/26)
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- Selective iron-catalyzed oxidation of phenols and arenes with hydrogen peroxide: Synthesis of vitamin e intermediates and vitamin k3
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(Figure Presented). Pumping iron! Convenient iron-based catalyst systems for the selective oxidation of arenes and phenols with hydrogen peroxide to give 1, 4-quinones have been developed. This selective oxidation reaction takes place under mild conditions (room temperature, alcoholic solvents) with H 2O2 as the terminal oxidant.
- Moeller, Konstanze,Wienhoefer, Gerrit,Schroeder, Kristin,Join, Benoit,Junge, Kathrin,Beller, Matthias
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experimental part
p. 10300 - 10303
(2010/10/21)
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- A novel process for selective Ruthenium-Catalyzed oxidation of naphthalenes and phenols
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Arenes are selectively oxidized to the corresponding quinones employing ruthenium(2,2′,6′:2″-terpyridine)(2,6-pyridinedicarboxylate) [Ru(tpy)(pydic] as catalyst and hydrogen peroxide as the terminal oxidant. Applying alkylated naphthalenes and phenols, benzo- and naphthoquinones are obtained in up to 93% yield. The industrially interesting oxidation of 2-methylnaphthalene gave 74% of the corresponding quinones and 60% of menadione (vitamin K3). 2,3,5-Trimethylbenzoquinone which constitutes the key intermediate for vitamin E is obtained in 83% yield.
- Wienhoefer, Gerrit,Schroeder, Kristin,Moeller, Konstanze,Junge, Kathrin,Beller, Matthias
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scheme or table
p. 1615 - 1620
(2010/09/05)
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- A novel and convenient process for the selective oxidation of naphthalenes with hydrogen peroxide
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A practical ruthenium phase-transfer catalyst (Ru-PTC) system for the oxidation of naphthalene derivatives has been developed. Substituted 1,4-quinones are obtained in good selectivity and yield in water without the addition of any organic solvent and acid. By applying the optimized conditions the feed additive menadione (vitamin K3) is obtained from 2-methylnaphthalene with 64 % yield and 73 % selectivity.
- Shi, Feng,Tse, Man Kin,Beller, Matthias
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p. 303 - 308
(2008/02/05)
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- Chromium(VI) oxide-catalyzed oxidation of arenes with periodic acid
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Chromium(VI) oxide was found to catalyze the oxidation of arenes such as naphthalenes and anthrathene to the corresponding quinones with periodic acid as the terminal oxidant in acetonitrile. 2-Methylnaphthalene was oxidized smoothly to 2-methyl-1,4-naphthoquinone (vitamin K3) by the catalytic system in high yield and regioselectivity.
- Yamazaki, Shigekazu
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p. 3355 - 3357
(2007/10/03)
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- Neuroprotection in the MPTP parkinsonian C57BL/6 mouse model by a compound isolated from tobacco
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Epidemiological evidence suggests a lower incidence of Parkinson's disease in smokers than in nonsmokers. This evidence, together with the lower levels of brain monoamine oxidase (MAO) activity in smokers and the potential neuroprotective properties of MAO inhibitors, prompted studies which led to the isolation and characterization of 2,3,6-trimethyl-1,4-naphthoquinone (TMN), an MAO-A and MAO-B inhibitor which is present in tobacco and tobacco smoke. Results of experiments reported here provide evidence that this compound protects against the MPTP-mediated depletion of neostriatal dopamine levels in the C57BL/6 mouse. These results support the hypothesis that the inhibition of MAO by constituents of tobacco smoke may be related to the decreased incidence of Parkinson's disease in smokers.
- Castagnoli, Kay P.,Steyn, Stefanus J.,Petzer, Jacobus P.,Van Der Schyf, Cornelis J.,Castagnoli Jr., Neal
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p. 523 - 527
(2007/10/03)
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- Synthesis and redox potentials of methylated vitamin K derivatives
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We report the synthesis of derivatives of vitamin K3 as well as of vitamins K1 and K2 containing a different number of methyl groups in various positions in order to reduce their redox potentials and to change systematically their steric features. The long aliphatic chain of vitamins K1 and K2 is simulated by an undecyl chain or a methyl group, respectively. The redox potentials of the first reduction step were measured by cyclic voltammetry in DMF. These compounds are relevant for studies of the structure-function relationship of vitamin K dependent enzymes and the investigation of electron transfer reactions in photosynthetic reaction centers.
- Schmid, Ralf,Goebel, Friederike,Warnecke, Andre,Labahn, Andreas
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p. 1199 - 1202
(2007/10/03)
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- Naphthalene anti-psoriatic agents
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Psoriasis in mammals is relieved by topically administering naphthalenes of the formula: STR1 wherein: R1 is lower alkoxy or optionally substituted phenoxy; R2 is hydrogen, lower alkyl, optionally substituted phenyl or optionally substituted phenyl-lower-alkyl; R3 is hydrogen, lower alkyl, lower alkoxy, halo, optionally substituted phenyl, optionally substituted phenyl-lower-alkyl or optionally substituted phenyl-lower-alkoxy, and m is 1 or 2; X and Y are different and are selected from the group consisting of hydrogen, R4 and -C(O)W, wherein W is alkyl of one to seven carbon atoms, optionally substituted phenyl or optionally substituted benzyl; and R4 is lower alkyl or optionally substituted phenyl-lower-alkyl.
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- METHOD FOR TREATING DISEASE STATES IN MAMMALS WITH NAPHTHALENE LIPOXYGENASE-INHIBITTNG AGENTS
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Psoriasis in mammals is relieved by topically administering naphthalenes of the formula: wherein: R1 is lower alkoxy or optionally substituted phenoxy, R2 is the same as R1, or R2 is hydrogen, lower alkyl, optionally substituted phenyl or optionally substituted phenylalkyl, R3 is hydrogen, lower alkyl, lower alkoxy, halo, optionally substituted phenyl, optionally substituted phenyl-lower-alkyl or optionally substituted phenyl-lower-alkoxy, and m is 1 or 2; both X groups are the same and X is either -C(O)OR4 or -C(O)NR5R6 , wherein R4 is alkyl, phenyl or benzyl optionally substituted with one or two lower alkyl groups, lower alkoxy groups or halo; and R5 and R6 are independently hydrogen, lower alkyl, cycloalkyl or phenyl optionally substituted with one or two lower alkyl groups, lower alkoxy groups or halo. The compounds of this invention are also useful for the treatment of disease-states caused by lipoxygenase activity in mammals, particularly 5-lipoxygenase activity, when administered systemically.
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- Naphthalene lipoxygenase-inhibiting agents
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Psoriasis in mammals is relieved by topically administering naphthalenes of the formula: STR1 wherein: R1 is lower alkoxy or optionally substituted phenoxy; R2 is hydrogen, lower alkyl, optionally substituted phenyl or optionally substituted phenylalkyl; R3 is hydrogen, lower alkyl, lower alkoxy, halo, optionally substituted phenyl, optionally substituted phenyl-lower-alkyl or optionally substituted phenyl-lower-alkoxy, and m is 1 or 2; X and Y are different and are either R4 or --C(O)W wherein R4 is lower alkyl or optionally substituted phenyl-lower-alkyl; W is --OR5 or --NR6 R7, wherein R5 is alkyl, optionally substituted phenyl or optionally substituted benzyl; and R6 and R7 are independently hydrogen, lower alkyl, cycloalkyl or optionally substituted phenyl. The compounds of this invention are also useful for the treatment of disease-states caused by lipoxygenase activity in mammals, particularly 5-lipoxygenase activity, when administered systemically.
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- N.M.R. Study of Bond Orders in o- and p-Quinones
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The 4J(Me-CC-H) coupling constsnt, previously established as a probe of bond order,1-3 was used to examine bond orders in a number of quinones.It was found that the presence of a quinone moiety does not cause bond localization in aromatic rings adjacent to the quinone ring.
- Gready, Jill E.,Hata, Kazumi,Sternhell, Sever,Tansey, Charles W.
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p. 593 - 600
(2007/10/02)
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- Naphthalene anti-psoriatic agents
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Psoriasis in mammals is relieved by topically administering naphthalenes of the formula: STR1 wherein: R1 is lower alkoxy or optionally substituted phenoxy; R2 is hydrogen, lower alkyl, optionally substituted phenyl or optionally substituted phenylalkyl; R3 is hydrogen, lower alkyl, lower alkoxy, halo, optionally substituted phenyl, optionally substituted phenyl-lower-alkyl or optionally substituted phenyl-lower-alkoxy, and m is 1 or 2; X and Y are different and are either R4 or --C(O)W wherein R4 is lower alkyl or optionally substituted phenyl-lower-alkyl; W is --OR5 or --NR6 R7, wherein R5 is alkyl, optionally substituted phenyl or optionally substituted benzyl; and R6 and R7 are independently hydrogen, lower alkyl, cycloalkyl or optionally substituted phenyl.
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- The Oxidation of Methylbenzenes and Naphthalenes to Quinones with H2O2 in the Presence of Palladium Catalyst
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Methylbenzenes and naphthalenes were oxidized to quinones with aqueous(60percent) H2O2 in acetic acid in the presence of a 0.24 wtpercent Pd(II)-sulfonated polystyrene type resin.The selectivities to quinones were higher in naphthalenes than in methylbenzenes.Among the naphthalenes used, 2-methylnaphthalene, 2,3-dimethylnaphthalene, and 2,6-dimethylnaphthalene gave 1,4-quinones in good yields (50-64percent).The increase in the reaction temperature increased the selectivity to quinones from 40percent at 20 deg C to 70percent at 70 deg C.
- Yamaguchi, Satoru,Inoue, Masami,Enomoto, Saburo
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p. 2881 - 2884
(2007/10/02)
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- Mechanistic Studies on the Oxidation of Naphthalenes and Methylbenzenes to Quinones with H2O2 in the Presence of Pd(II) Catalysts
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The oxidation of naphthalenes and methylbenzenes to quinones with aqueous 60 percent hydrogen peroxide in the presence of a 0.24 percent Pd(II)-sulfonated polystyrene-type resin catalyst was studied.The presence of electron-donating substituents on carbon-2 of naphthalenes accelerated the oxidation. A reaction path by way of hydroxylated intermediates to the quinones is proposed.By using the MINDO/3 method, quantum chemical indices such as the superdelocalizability for electrophilic species (SEr) and for radical species (SRr), and the net charge (Qr) of naphthalenes, methylbenzenes, and naphthols were calculated.The activity in the above reaction could be explained in terms of both Qr and SEr.The decrease of the selectivity was correlated with side reactions by radical species attacking the sites of largest SRr.Keywords - oxidation; hydrogen peroxide; naphthalene; methylbenzene; palladium catalyst; 1,4-naphthoquinone; sulfonated polystyrene-type resin
- Yamaguchi, Satoru,Shinoda, Hiroyuki,Inoue, Masami,Enomoto, Saburo
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p. 4467 - 4473
(2007/10/02)
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- PREPARATION OF NAPHTHALDEHYDES BY CERIUM(IV)AMMONIUM NITRATE OXIDATION OF METHYLNAPHTHALENES.
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Naphthalenes with an Me group in the 1-position gave aldehydes in good to excellent yields when oxidized with cerium(IV) ammonium nitrate (CAN) in 50percent HOAc at 85 deg C.Under the same conditions methylnaphthalenes with no Me group in a peri position gave aldehydes in fair yields but also significant amounts of 1,4-naphthoquinone.
- Sydnes, Leiv K.,Burkow, Ivan C.,Hansen, Sissel H.
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p. 5703 - 5706
(2007/10/02)
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- CERIUM CATALYZED PERSULFATE OXIDATION OF POLYCYCLIC AROMATIC HYDROCARBONS TO QUINONES
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A practical synthesis of polycyclic quinones from the parent hydrocarbons is described.The twophase oxidation of hydrocarbons was accomplished by using ammonium persulfate in the catalytic presence of cerium ammonium sulfate, silver nitrate, and sodium dodecyl sulfate.The reaction conditions and scope have been discussed in detail.
- Skarzewski, Jacek
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p. 4997 - 5000
(2007/10/02)
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- Catalytic Asymmetric Induction in Oxidation Reactions. Synthesis of Optically Active Epoxynaphthoquinones
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Optically active 2,3-epoxides of a variety of substituted 1,4-naphthoquinones have been prepared in an asymmetric synthesis.Enantiomeric excess of up to 45percent were realized.Some data could be obtained concerning the influence of substituents on the en
- Pluim, Henk,Wynberg, Hans
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p. 2498 - 2502
(2007/10/02)
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