- Synthetic method 4 - alkoxyphenol compounds
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The invention discloses a synthetic method of 4 - alkoxyphenol compounds, and belongs to the field of organic chemical synthesis. The method is as follows: An aryl alkyl ether compound is added to the sealing tube. The catalyst dimerization acetic acid rhodium and the oxidizing agent iodobenzene diethyl ester are added, a solvent trifluoroacetic anhydride is added, and the 4 -alkoxyphenol compound is prepared by heating reaction. To the invention, high regioselectivity direct hydroxylation of the aryl alkyl ether compound is realized, the application range of the substrate is wide, the yield is high, the activity after amplification reaction does not significantly decay, and higher yield is still obtained. The utility model has good practicability and industrial application prospect.
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Paragraph 0049-0051
(2021/09/29)
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- Para -Selective hydroxylation of alkyl aryl ethers
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para-Selective hydroxylation of alkyl aryl ethers is established, which proceeds with a ruthenium(ii) catalyst, hypervalent iodine(iii) and trifluoroacetic anhydride via a radical mechanism. This protocol tolerates a wide scope of substrates and provides a facile and efficient method for preparing clinical drugs monobenzone and pramocaine on a gram scale.
- Zhu, Runqing,Sun, Qianqian,Li, Jing,Li, Luohao,Gao, Qinghe,Wang, Yakun,Fang, Lizhen
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supporting information
p. 13190 - 13193
(2021/12/16)
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- Phosphination of Phenol Derivatives and Applications to Divergent Synthesis of Phosphine Ligands
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We describe a general and efficient protocol for the synthesis of organophosphine compounds from phenols and phosphines (R2PH) via a metal-free C-O bond cleavage and C-P bond formation process. This approach exhibits broad substrate scope and excellent functional group tolerance. The synthetic utilities of this protocol were demonstrated by the synthesis of chiral ligands via the various transformations of cyano groups and their applications in asymmetric catalysis.
- Li, Chenchen,Zhang, Kezhuo,Zhang, Minghao,Zhang, Wu,Zhao, Wanxiang
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supporting information
p. 8766 - 8771
(2021/11/20)
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- Hollow, mesoporous, eutectic Zn1?xMgxO nano-spheres as solid acid-base catalysts for the highly regio-selectiveO-methylation of 1,2-diphenols
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The highly regio-selectiveO-methylation of catechol with dimethyl carbonate (DMC), catalyzed by a solid acid-base catalyst, is an environmentally friendly chemical process for industrial production of guaiacol. However, a guaiacol yield below 84% and high reaction temperature above 280 °C limit its industrial application. Here, hollow, mesoporous Zn1?xMgxO nano-spheres with a eutectic structure, denoted as Zn1?xMgxO HMNSs (x= 0.012-0.089), are facilely fabricatedviathe calcination of Mg2+/Zn2+ion-adsorbing carbon spheres at 500 °C in air. In theO-methylation of catechol with DMC at 180 °C, Zn1?xMgxO HMNSs (x= 0.052) afford guaiacol in 95.5% yield with a complete catechol conversion. Furthermore, 89.0-95.3% mono-ether yields with high 1,2-diphenol conversions (94.5-100%) are also obtained for the other 1,2-diphenols bearing -CH3and -Br groups. Moreover, a plausible mechanism for highly selectiveO-methylation of catechol with DMC is proposed, in which the single-site activation and double-site activation of phenolic hydroxyls by the basic oxygen of Mg-O afford guaiacol and veratrole, respectively.
- Liu, Jie,Ma, Xuebing,Wang, Xuri,Xie, Guangxin,Yin, Zuyong,Zhang, Jianing
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p. 7454 - 7466
(2021/11/23)
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- Mustard Carbonate Analogues as Sustainable Reagents for the Aminoalkylation of Phenols
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N,N-dialkyl ethylamine moiety can be found in numerous scaffolds of macromolecules, catalysts, and especially pharmaceuticals. Common synthetic procedures for its incorporation in a substrate relies on the use of a nitrogen mustard gas or on multistep syntheses featuring chlorine hazardous/toxic chemistry. Reported herein is a one-pot synthetic approach for the easy introduction of aminoalkyl chain into different phenolic substrates through dialkyl carbonate (β-aminocarbonate) chemistry. This new direct alcohol substitution avoids the use of chlorine chemistry, and it is efficient on numerous pharmacophore scaffolds with good to quantitative yield. The cytotoxicity via MTT of the β-aminocarbonate, key intermediate of this synthetic approach, was also evaluated and compared with its alcohol precursor.
- Annatelli, Mattia,Trapasso, Giacomo,Salaris, Claudio,Salata, Cristiano,Castellano, Sabrina,Aricò, Fabio
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supporting information
p. 3459 - 3464
(2021/05/24)
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- Light assisted O-alkylation of phenols to ethers using layered double oxides catalyst under green and mild conditions
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O-alkylation of phenols with dialkyl carbonates to ethers over layered double oxides (LDOs) catalyst under light irradiation is described. A base additive is not required when using the longer-chain diethyl carbonate as an alkylating agent owing to the sufficient basicity provided by LDOs. The synergism of substrate phenols molecules absorbing light to reach the first excited states with acid–base pairs of catalyst enhanced the interaction of reactant molecules with the surface of LDOs, simultaneously accelerating the cleavage of phenolic hydroxyl groups. A variety of phenols are tolerated in this system. This work reports a simple and environmentally benign catalytic process for the dehydrogenation of phenolic hydroxyl groups.
- Wang, Ruiyi,Wang, Xiaoyu,Zheng, Zhanfeng
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- Efficient dealkylation of aryl alkyl ethers catalyzed by Cu2O
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An efficient protocol for dealkylation of aryl alkyl ethers under the catalysis of inexpensive and easily reusable Cu2O has been described. The phenol products were obtained in high yields, and a range of functional groups were well tolerated. The choice of solvent is critical to the catalysis, and CH3OH proved to be the optimal choice. Mechanistic investigations showed that this reaction possibly proceeds via a single-electron transfer (SET) process.
- Liu, Lingxian,Li, Zengguang,Chen, Changjun,Li, Huanrong,Xu, Lijin,Yu, Zhiyong
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supporting information
p. 2447 - 2453
(2018/04/11)
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- Metal-Free Electrocatalytic Aerobic Hydroxylation of Arylboronic Acids
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Hydroxylation of arylboronic acids to aryl alcohols was realized by a scalable electrocatalytic method. The present electrochemical hydroxylation employs low-cost methyl viologen as an organic cathodic electrocatalyst and involves O2 as a green and sustainable reactant. The electrochemical kinetic studies shown here can be a powerful tool to gain rich mechanistic and kinetic information and thus an in-depth understanding of the electrocatalytic mechanism.
- Luo, Jian,Hu, Bo,Sam, Alyssa,Liu, T. Leo
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supporting information
p. 361 - 364
(2018/01/28)
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- Au-Pd alloy nanoparticles supported on layered double hydroxide for heterogeneously catalyzed aerobic oxidative dehydrogenation of cyclohexanols and cyclohexanones to phenols
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Phenol, an important industrial chemical, is widely produced using the well-developed cumene process. However, demand for the development of a novel alternative method for synthesizing phenol from benzene has been increasing. Herein, we report a novel system for the synthesis of phenols through aerobic oxidative dehydrogenation of cyclohexanols and cyclohexanones, including ketone-alcohol (KA) oil, catalyzed by Mg-Al-layered double hydroxide (LDH)-supported Au-Pd alloy nanoparticles (Au-Pd/LDH). Alloying of Au and Pd and basicity of LDH are key factors in achieving the present transformation. Although monometallic Au/LDH, Pd/LDH, and their physical mixture showed almost no catalytic activity, Au-Pd/LDH exhibited markedly high catalytic activity for the dehydrogenative phenol production. Mechanistic studies showed that β-H elimination from Pd-enolate species is accelerated by Au species, likely via electronic ligand effects. Moreover, the effect of supports was critical; despite the high catalytic performance of Au-Pd/LDH, Au-Pd bimetallic nanoparticles supported on Al2O3, TiO2, MgO, and CeO2 were ineffective. Thus, the basicity of LDH plays a deterministic role in the present dehydrogenation possibly through its assistance in the deprotonation steps. The synthetic scope of the Au-Pd/LDH-catalyzed system was very broad; various substituted cyclohexanols and cyclohexanones were efficiently converted into the corresponding phenols, and N-substituted anilines were synthesized from cyclohexanones and amines. In addition, the observed catalysis was truly heterogeneous, and Au-Pd/LDH could be reused without substantial loss of its high performance. The present transformation is scalable, utilizes O2 in air as the terminal oxidant, and generates water as the only by-product, highlighting the potential practical utility and environmentally benign nature of the present transformation. Dehydrogenative aromatization of cyclohexanols proceeds through (1) oxidation of cyclohexanols to cyclohexanones; (2) dehydrogenation of cyclohexanones to cyclohexenones; and (3) disproportionation of cyclohexenones to afford the desired phenols. In the present Au-Pd/LDH-catalyzed transformation, the oxidation of the Pd-H species is included in the rate-determining step.
- Jin, Xiongjie,Taniguchi, Kento,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 5371 - 5383
(2016/07/29)
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- REGIOREGULAR COPOLYMERS AND METHODS FOR MAKING SAME
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Methods for producing regioregular poly(aryl ethynyl)-poly(aryl vinyl) and monomers for preparing the regioregular poly(aryl ethynyl)-poly(aryl vinyl) polymers are described herein. Regioregular poly(aryl ethynyl)-poly(aryl vinyl) are useful for electronics, among other things.
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Paragraph 0032
(2015/04/15)
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- Intramolecular charge transfer interactions and molecular order of rod like mesogens
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A mesogenic 4-((4-(alkoxy)phenoxy)carbonyl)phenyl-4-(dimethylamino)benzoate series with terminal chains varying from C2 to C12 carbons (even number carbons only) are synthesised and their mesophase transitions are examined by hot-stage optical polarising microscopy as well as differential scanning calorimetry. Accordingly, enantiotropic nematic mesophase for all the homologs and an additional smectic A phase for the C12 homolog is observed. Powder X-ray diffraction studies confirm the interdigitated bilayer organization in the smectic A phase for the C12 homolog. It is remarkable that the mesogens under investigation only differ in the linking unit i.e. ester versus imine in contrast to recently reported mesogens, yet show a large difference in certain properties. Accordingly, the crystal structure of the C4 homolog reveals a triclinic lattice with P1 space group in which the molecules are packed in a slipped co-facial configuration. Additionally, a detailed investigation of the C12 mesogen by UV-visible and fluorescence spectroscopy as well as computational methods unveils interesting features. The fluorescence spectrum of the C12 mesogen is observed at 366 nm with a shoulder at 433 nm and a large solvent polarity induced red-shift is noticed in contrast to a structurally similar homolog examined recently. Further, the C12 mesogen in solvents such as ethyl acetate, dichloromethane, chloroform, tetrahydrofuran, acetonitrile and dimethyl sulfoxide exhibited dual emission. Therefore, density functional theory and time dependent density functional theory calculations are utilized to obtain insight. Besides variation in the dihedral angle between rings B and C for the C12 mesogen, it is found that the highest occupied molecular orbital (HOMO) is localized on the N,N-dimethylaminobenzene moiety while the lowest unoccupied molecular orbital (LUMO) is mostly concentrated on the phenyl benzoate unit. Time dependent-density functional theory (TD-DFT) calculations disclose the orbitals involved in the dominant excited state electronic transitions and their corresponding energies together with oscillator strength. The high resolution 1D and 2D separated local field (SLF) solid state 13C NMR investigation of the C12 mesogen lead to the orientational order parameters of the phenyl rings of the core in the SmAd phase. The temperature versus alignment induced chemical shifts reveals an increase in chemical shifts with a decrease in temperature in the smectic Ad phase in concurrence with order parameter values. Thus, understanding the photophysical properties of mesogens with dimethylamino moieties would facilitate better design of molecules for application in organic light emitting diodes for polarized emission.
- Reddy, M. Guruprasad,Lobo, Nitin P.,Varathan,Easwaramoorthi,Narasimhaswamy
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p. 105066 - 105078
(2015/12/30)
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- Facile conversion of para-benzoquinones to para-alkoxyphenols with primary/secondary alcohols and amberlyst-15: A process showing novel reducing property of such alcohols
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A new efficient methodology has been developed for the synthesis of para-alkoxyphenols, an important group of anti-melanoma compounds, by heating alcoholic solutions of para-benzoquinones in the presence of amberlyst-15. The most notable feature here is the behaviour of the used primary or secondary alcohol as an effective reducing agent.
- Mondal, Rina,Guha, Chayan,Mallik, Asok K.
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supporting information
p. 86 - 89
(2014/01/06)
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- The rearrangement of tert -butylperoxides for the construction of polysubstituted furans
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The Bronsted acid catalyzed rearrangement of tert-butyl peroxides provides a new strategy to construct 2,3-disubstituted furans via 1,2-aryl migration. In addition, tert-butyl peroxides could also be transformed into 2,3,5-trisubstituted or 2,5-disubstituted furans through a sequence of base-catalyzed Kornblum-DelaMare rearrangements and acid-promoted Paal-Knorr reactions.
- Zheng, Xiaojian,Lu, Shenglin,Li, Zhiping
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supporting information
p. 5432 - 5435
(2013/11/19)
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- Side-chain liquid-crystalline polymers based on flexible rod-like mesogen directly attached to backbone
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In this article, we report the synthesis and characterization of a new end-on side-chain liquid crystalline polymer (SCLCP), poly[4-(4′- alkoxyphenyloxymethylene)styrene] [denoted as Poly(n-POMS), where n is the carbon number of the alkyl tail, n = 2, 4, 6, 8, 12, 16], with the flexible rod-like mesogenic side-chain directly attached to the polymer backbone without flexible spacer. The polymer was obtained by using free radical polymerization. The chemical structures of Poly(n-POMS) and the corresponding monomer were characterized using various techniques with satisfactory analysis data. A combination analysis of differential scanning calorimetry, polarized light microscopy, small angle X-ray scattering, and wide-angle X-ray diffraction has been conducted to investigate the phase behavior of Poly(n-POMS). Poly(2-POMS), Poly(4-POMS), and Poly(6-POMS) are amorphous. Poly(8-POMS) develops partially into the liquid crystal phase, and Poly(12-POMS) and Poly(16-POMS) self-assembly into the smectic A (SmA) phase. Upon increasing temperature, the phase transition of Poly(16-POMS) follows the sequence of SmA1 ? SmA2 ? isotropic (I), which may be attributed to the conformation isomerization of the flexible rod-like mesogens.
- Zheng, Jun-Feng,Yu, Zhen-Qiang,Liu, Xin,Chen, Xiao-Fang,Yang, Shuang,Chen, Er-Qiang
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p. 5023 - 5031
(2013/01/15)
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- Synthesis and SAR of selective small molecule neuropeptide y Y2 receptor antagonists
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Highly potent and selective small molecule neuropeptide Y Y2 receptor antagonists are reported. The systematic SAR exploration of a hit molecule N-(4-ethoxyphenyl)-4-[hydroxy(diphenyl)methyl]piperidine-1-carbothioamide, identified from HTS, led to the discovery of highly potent NPY Y2 antagonists 16 (CYM 9484) and 54 (CYM 9552) with IC50 values of 19 nM and 12 nM respectively.
- Mittapalli, Gopi Kumar,Vellucci, Danielle,Yang, Jun,Toussaint, Marion,Brothers, Shaun P.,Wahlestedt, Claes,Roberts, Edward
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scheme or table
p. 3916 - 3920
(2012/07/03)
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- Dialkoxybenzene and dialkoxyallylbenzene feeding and oviposition deterrents against the cabbage looper, trichoplusia ni: Potential insect behavior control agents
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The antifeedant, oviposition deterrent, and toxic effects of individual dialkoxybenzene compounds/sets and of hydroxy- or alkoxy-substituted allylbenzenes, obtained through Claisen rearrangement of substituted allyloxybenzenes, were assessed against the cabbage looper, Trichoplusia ni, in laboratory bioassays. Most of the compounds/sets strongly deterred larval feeding, with some exhibiting mild toxic and oviposition deterrent effects as well. Some of the compounds/sets were more active than the commercial insect repellent, DEET (N,N-diethyl-m-toluamide), as both feeding and oviposition deterrents against the cabbage looper. On the basis of the obtained oviposition data a general hypothesis was proposed regarding the oviposition sites: one binding mode with the alkyl and allyl groups on the same side of the benzene ring resulted in deterrence, the other with alkyl and allyl groups on opposite sides of the benzene ring resulted in stimulation. The results suggest some structure-activity relationships useful in improving the efficacy of the compounds and designing new, nontoxic insect control agents for agriculture.
- Akhtar, Yasmin,Yu, Yang,Isman, Murray B.,Plettner, Erika
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scheme or table
p. 4983 - 4991
(2011/08/06)
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- Sn(IV) phosphonates as catalysts in solvent-free Baeyer-Villiger oxidations using H2O2
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We have designed a new family of layered Sn(iv)phosphonate (SnPP) materials which are very efficient catalysts in the BV oxidation of aromatic aldehydes without any solvent and using aqueous H2O2 (30%) as the oxidant. The Royal Society of Chemistry.
- Kirumakki, Sharath,Samarajeewa, Sandani,Harwell, Robert,Mukherjee, Atashi,Herber, Rolfe H.,Clearfield, Abraham
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scheme or table
p. 5556 - 5558
(2009/04/13)
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- Screening of dialkoxybenzenes and disubstituted cyclopentene derivatives against the cabbage looper, Trichoplusia ni, for the discovery of new feeding and oviposition deterrents
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The antifeedant, oviposition deterrent, and toxic effects of dialkoxybenzene minilibraries and of disubstituted cyclopentene minilibraries (i.e., consisting of four to five compounds) along with their pure constituent compounds were assessed against third instar larvae and adults of the cabbage looper, Trichoplusia ni, in laboratory bioassays in a search for new insect control agents. These compounds mimic naturally occurring bioactive odorants and tastants and are relatively easily prepared from commodity chemicals. Most of these libraries strongly deterred larval feeding, with some exhibiting strong toxic and oviposition deterrent effects as well. Our results suggest some structure-function relationships within these libraries. Replacement of a methyl group with larger alkyl substituents increased the feeding deterrent effects in most cases. The presence of a free hydroxyl group, irrespective of the carbon framework or alkyl substituent, served to reduce feeding deterrent effects in all series of compounds. Further, exceeding a certain group size also generally had a detrimental effect. This information will be useful in designing new insect control agents for agriculture. Some of these libraries and compounds may have potential for development as commercial insecticides.
- Akhtar, Yasmin,Isman, Murray B.,Paduraru, Peggy M.,Nagabandi, Srinivas,Nair, Ranjeet,Plettner, Erika
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scheme or table
p. 10323 - 10330
(2009/10/02)
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- (2R)-2-Methylchromane-2-carboxylic acids: Discovery of selective PPARα agonists as hypolipidemic agents
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A SAR study was conducted on chromane-2-carboxylic acid toward selective PPARα agonisim. As a result, highly potent, and selective PPARα agonists were discovered. The optimized compound 43 exhibited robust lowering of total cholesterol levels in hamster and dog animal models.
- Koyama, Hiroo,Boueres, Julia K.,Miller, Daniel J.,Berger, Joel P.,MacNaul, Karen L.,Wang, Pei-Ran,Ippolito, Marc C.,Wright, Samuel D.,Agrawal, Arun K.,Moller, David E.,Sahoo, Soumya P.
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p. 3347 - 3351
(2007/10/03)
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- Monooxygenation of aromatic compounds by dioxygen with bioinspired systems using non-heme iron catalysts and tetrahydropterins: Comparison with other reducing agents and interesting regioselectivity favouring meta-hydroxylation
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Monooxygenation of aromatic compounds by dioxygen in the presence of catalytic amounts of an iron(II) salt and tetrahydropterins as reducing agents occurs with a regioselectivity favouring meta-hydroxylation of arenes bearing an electron-donating substituent, such as anisole, phenetole, toluene, and ethylbenzene. Comparison of similar systems using various reducing agents showed that only tetrahydropterins and ascorbate led to such a major meta-hydroxylation. The tetrahydropterin- and ascorbate-dependent systems should be useful for the preparation of meta-hydroxylated metabolites of aromatic drugs, as shown here in the case of diclofenac.
- Mathieu, Delphine,Bartoli, Jean Fran?ois,Battioni, Pierrette,Mansuy, Daniel
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p. 3855 - 3862
(2007/10/03)
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- One-pot synthesis of phenols from aromatic aldehydes by Baeyer-Villiger oxidation with H2O2 using water-tolerant Lewis acids in molecular sieves
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The heterogeneous oxidation systems Sn-Beta/H2O2 and Al-Beta/H2O2 were both active for the Baeyer-Villiger oxidation of aromatic aldehydes. With alkoxy substituents in ortho and especially in para position, the corresponding formate ester was the primary reaction product with excellent selectivity. The highest selectivity toward the ester was obtained with the Sn-Beta catalyst in dioxane as solvent. High selectivities of the corresponding phenol could be obtained by employing ethanol or aqueous acetonitrile as solvent with Sn-Beta. Al-Beta was more efficient as catalyst for both Baeyer-Villiger oxidation and ester hydrolysis and, thus achieved high yields for the corresponding alcohol. However, this was a less selective catalyst than Sn-Beta zeolite. Sn-Beta was a chemoselective catalyst when the aldehyde reactant contained olefinic groups in an alkyl chain. With these reactants, the Al-zeolite gave no activity. Other classical BV oxidants, e.g., peracids, also yielded the epoxidation products. Thus, Sn-Beta catalysts open a new entry to aromatic phenols with unsaturated alkyl substituents that are interesting intermediates in the chemical industry.
- Corma, Avelino,Fornes, Vicente,Iborra, Sara,Mifsud, Maria,Renz, Michael
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- Demand-based thiolate anion generation under virtually neutral conditions: Influence of steric and electronic factors on chemo- and regioselective cleavage of aryl alkyl ethers
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Thiolate anions have been generated in a "demand-based" fashion under virtually neutral conditions for chemoselective deprotection of aryl alkyl ethers. Solvents play the critical role in making the reaction effective and should have high values of ε (>30), molecular polarizabilities (>10), and DN (>27) and low values of AN (>14). However, it is the combined effect of all of these physical properties that make a particular solvent effective. The reaction rates of cleavage of various aryl alkyl ethers are dependent on the steric crowding around the O-alkyl carbon and follow the order propargyl ≈ allyl ≈ benzyl > methyl > ethyl. Electron-withdrawing substituents increase the rate of ether cleavage reaction. The influence of the steric and electronic factors have been successfully exploited for selective deprotection of aryl alkyl ethers during inter- and intramolecular competitions.
- Chakraborti, Asit K.,Sharma, Lalima,Nayak, Mrinal K.
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p. 6406 - 6414
(2007/10/03)
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- Design and synthesis of a novel and potent series of inhibitors of cytosolic phospholipase A2 based on a 1,3-disubstituted propan-2-one skeleton
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Using knowledge of the substrate specificity of cPLA2 (phospholipases A2), a novel series of inhibitors of this enzyme were designed based upon a three point model of inhibitor binding to the enzyme active site comprising a lipophilic anchor, an electrophilic serine "trap", and an acidic binding moiety. The resulting 1,3-diheteroatom-substituted propan-2-ones were evaluated as inhibitors of cPLA2 in both aggregated bilayer and soluble substrate assays. Systematic variation of the lipophilic, electrophilic, and acidic groups revealed a well-defined structure-activity relationship against the enzyme. Optimization of each group led to compound 22 (AR-C70484XX), which contains a decyloxy lipophilic side chain, a 1,3-diaryloxypropan-2-one moiety as a unique serine trap, and a benzoic acid as the acidic binding group. AR-C70484XX was found to be among the most potent in vitro inhibitors of cPLA2 described to date being more than 20-fold more active against the isolated enzyme (IC50 = 0.03 μM) than the standard cPLA2 inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3), and also greater than 10-fold more active than AACOCF3 against the cellular production of arachidonic acid by HL60 cells (IC50 = 2.8 μM).
- Connolly, Stephen,Bennion, Colin,Botterell, Sarah,Croshaw, Pamela J.,Hallam, Catherine,Hardy, Kim,Hartopp, Paul,Jackson, Clive G.,King, Sarah J.,Lawrence, Louise,Mete, Antonio,Murray, David,Robinson, David H.,Smith, Gillian M.,Stein, Linda,Walters, Iain,Wells, Edward,Withnall, W. John
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p. 1348 - 1362
(2007/10/03)
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- Novel synthesis of monoethers of hydroquinone and resorcinol on soluble polymer-supports
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Monoethers of hydroquinone and resorcinol were easily prepared using PEG as soluble polymer-supports, monoprotection group and phase transfer catalyst with good yields and high selectivity of functionlization in homogenous solution.
- Yang, Guichun,Chen, Zuxing,Zhang, Zhaojun,Qiu, Xiaoling
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p. 3637 - 3642
(2007/10/03)
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- Iron polynitroporphyrins bearing up to eight β-nitro groups as interesting new catalysts for H2O2-dependent hydrocarbon oxidation: Unusual regioselectivity in hydroxylation of alkoxybenzenes
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A series of iron porphyrins bearing one to eight β-nitro substituents were synthesized and evaluated as catalysts for hydrocarbon oxidation with H2O2; iron porphyrins bearing five or six β-nitro groups were the best catalysts for cyclooctene epoxidation and adamantane or anisole hydroxylation without need of a cocatalyst, and led to very different regioselectivities with either H2O2 or PhIO as oxidants, as shown by an unusual ortho-hydroxylation of alkoxybenzenes highly favored in the H2O2-dependent oxidations.
- Bartoli,Barch,Palacio,Battioni,Mansuy
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p. 1718 - 1719
(2007/10/03)
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- β1- and β2-adrenoceptor antagonist activity of a series of para- substituted N-isopropylphenoxypropanolamines
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To further explore the structure-activity relationships of β- adrenoceptor (β-AR) antagonists, a series of 25 para-substituted N- isopropylphenoxy-propanolamines were synthesised, nine of which are new compounds. All have been examined for their ability to antagonise β1-ARs in rat atria and β2-ARs in rat trachea. Substitution in the para-position of the phenyl ring is thought to confer β3-specificity and the selectivity of these compounds for the β1-AR ranges from 1.5-234. None of the compounds tested were selective for the β2-AR. Of the 25 compounds studied, 22 had reasonable (pA2 > 7) potencies for the rat β1-AR. Only compound 1 displayed reasonable (pA2 > 7) potency for the rat β2-AR. Twenty two compounds were used as the training set for comparative molecular field analysis (CoMFA) of antagonist potency (pA2) at the rat β1- and β2-ARs. The inclusion of a number of additional physical characteristics improved the QSAR analysis over models derived solely using the CoMFA electrostatic and steric fields. The final models predicted the β1- and β2-AR potency of the compounds in the training set with high accuracy (r2 = 0.93 and 0.86 respectively). The final β1-AR model predicted the β1-potencies of two out of the three test compounds, not included in the training set, with residual PA2 values 2-AR model (residual pA2 values -0.38).
- Louis, Simon N.,Nero, Tracy L.,Iakovidis, Dimitri,Colagrande, Felicia M.,Jackman, Graham P.,Louis, William J.
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p. 919 - 937
(2007/10/03)
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- Color-stabilized basic monomers, process for producing the same and method for handling the same
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Color-stabilized basic monomers are provided. Said basic monomers are obtained by adding, to a basic monomer ?e.g. an N,N-dialkylaminoalkyl (meth)acrylate or an N,N-dialkylaminoalkyl (meth)acrylamide!, at least one member selected from the group consisting of amido group-containing compounds, phosphorous acid esters, phosphoric acid esters and phosphines and at least one phenol compound represented by the general formula: STR1 wherein R5, R6, R8 and R9 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and R7 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The color-stabilized basic monomers are more resistant to coloration when they are handled under such conditions that the oxygen concentration in the gas phase contacting therewith is 0.01 to 10% by volume.
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- O-alkylation of phenolic compounds via rare earth orthophosphate catalysts
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Carbocyclic/aliphatic ethers, for example anisole, quaicol, guaethol, p-methoxyphenol and ethylene dioxybenzene, are selectively prepared, in good yield, by reacting a phenolic compound, for example a phenol, hydroquinone, pyrocatechin, naphthol, or the like, with an alcohol, for example methanol, ethanol, isopropanol, ethylene glycol, etc., in gaseous phase, in the presence of a catalytically effective amount of a trivalent rare earth metal orthophosphate, for example a lanthanum, cerium or samarium orthophosphate, optionally doped with an alkali or alkaline earth metal, preferably cesium.
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- Synthesis of p-Di[1-13C]ethoxybenzene from [1-13C]iodoethane with high labeling efficiency
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p-Di[1-13C]ethoxybenzene was synthesized in high yield and with high labeling efficiency from hydroquinone and [1-13C]iodoethane in the presence of a base in dry acetone. Some p-[1-13C]ethoxyphenol was also formed, from which further p-di[1-13C]ethoxybenzene could be synthesized.
- Iida, Katsumi,Kajiwara, Masahiro
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p. 235 - 241
(2007/10/03)
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- Reductive-alkylation and aromatic coupling reactions of 1,4-benzoquinone derivatives promoted by ethylaluminum dichloride
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Reactions of several substituted 1,4-benzoquinones with ethylaluminum dichloride in dichloromethane were studied. It was found that some quinones undergo a new radical aromatic coupling under these conditions, while others undergo a 1,6-reductive O-alkylation.
- Ferreira, Vitor F.,Schmitz, Francis J.
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- Tilt Angle Variation as a Function of Chain Length and Temperature in the Smectic C Phases of p,Alkoxyphenyl-p,Alkoxybenzoates
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The variation of the tilt angle with temperature in the smectic C phase has generally been shown to be non-existent or very slow for compounds or mixtures with the nematic-smectic C transition, while in the case of systems with the smectic A-smectic C transition, a relation between the steepness of this variation, near the transition, and the width of the smectic A domain has been observed.In this work, the variation of tilt angle in the smectic C phase is described for p-alkoxyphenyl-p-alkoxybenzoate homologous series, for which the evolution of polymorphism can be controlled systematically, by varying stepwise the length of the aliphatic chains, and for which large domains can be obtained for each type of phase sequence, nematic-, smectic A- and isotropic-smectic C.After completing the discussion made previously on the incidence of chain length on polymorphism, we confirm that the variation of tilt angle with temperature is slowest for compounds with intermediate chain lengths corresponding to the largest smectic A temperature range; this variation becomes continuously steeper when the smectic A domain becomes narrow.In addition, we show that the same description can be extended to the other types of phase sequences, by using the hypothesis of a virtual smectic A-smectic C transition above the observed nematic- or isotropic-smectic C transition.In fact, short chain lengths for homologues with a nematic/smectic C transition, or long chain lengths for homologues with an isotropic/smectic C transition, lead to an increase of the tilt angle at the phase transition and to a decrease of the amplitude of its variation with temperature; in our description, this behaviour corresponds to an increase of the temperature range between the real and virtual transitions.As a consequence, the homologues with very short and very long chain lengths show a quasi temperature-independent tilt angle, while the other homologues present a tilt angle variation similar to that observed for compounds exhibiting a smectic C/smectic A transition.This feature indicates that there is no need to distinguish between different types of smectic C phase.
- Heinrich, B.,Guillon, D.
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- Hydride-promoted Demethylation of Methyl Phenyl Ethers
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Solutions of L-Selectride or SuperHydride in refluxing THF efficiently deprotect methyl phenyl ethers.L-Selectride is the more effective reagent, while electron-poor arenes work best.Unlike other hydride sources, these reagents permit ether cleavage without the reduction of aryl halides.
- Majetich, George,Zhang, Yong,Wheless, Karen
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p. 8727 - 8730
(2007/10/02)
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- Synthesis of 4-alkoxyaryl β-D-glucopyranosides and their inhibitory effects on histamine release from rat peritoneal mast cells induced by concanavalin A
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The inhibitory effects of newly synthesized 4-alkoxyaryl β-D- glucopyranosides on histamine release from rat peritoneal mast cells induced by concanavalin A were examined. A plot of hydrophobicity (k') against inhibitory activity of the compounds showed a distinct maximum, and 4- decyloxy-2,3,6-trimethylphenyl β-D-glucopyranoside was the most potent inhibitor among the tested compounds.
- Wang,Furukawa,Nihro,Kakegawa,Matsumoto,Satoh
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p. 570 - 575
(2007/10/02)
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- Synthesis and anti lipid-peroxidation activity of hydroquinone monoalkyl ethers
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A series of hydroquinone monoalkyl ethers was synthesized and evaluated for anti lipid-peroxidation activity in rat liver microsomes. 4-Hexyloxy- 2,3,6-trimethylphenol (9), having a low redox potential, as well as ascorbic acid exhibited the strongest anti lipid-peroxidation activity (IC50 = 4.2 x 10-7 M). Structure-activity relationship studies demonstrated that the inhibitory effect of hydroquinone monoalkyl ethers on lipid peroxidation was increased by the acquisition of an optimum hydrophobicity and decreased by an insufficient or excessive hydrophobicity.
- Nihro,Furukawa,Sogawa,Wang,Miyataka,Matsumoto,Miki,Satoh
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p. 576 - 579
(2007/10/02)
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- Process for the preparation of mono-ethers of hydroquinones
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Mono-ethers of hydroquinones of formula (I) STR1 wherein R represents alkyl, alkoxy-alkyl, cycloalkyl, aryl-alkyl, or cycloalkyl-alkyl, and R1 is hydrogen or alkyl, cycloalkyl, aryl-alkyl, or cycloalkyl-alkyl, are prepared by contacting the corresponding hydroquinones with the corresponding alcohols ROH, in the presence of a catalytic mixture consisting of (a) a strong acid (b) a halogen or a hydrohalic acid selected from HBr, HI, I2, and Br2, and (c) H2 O2 in a molar amount lower than that of the starting hydroquinone.
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- Process for the preparation of mono-ethers of hydroquinones
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Mono-ethers of hydroquinones of formula (I) wherein, R represents alkyl, alkoxy-alkyl, cycloalkyl, aryl-alkyl, or cycloalkyl-alkyl, and, R1 is hydrogen or alkyl, cycloalkyl, aryl-alkyl, or cycloalkyl-alkyl,are prepared by contacting the corresponding hydroquinones with the corresponding alcohols ROH, in the presence of a catalytic mixture consisting of a) a strong acid b) a halogen or a hydrohalic acid selected from HBr, HI, I2, and Br2, and c) H2O2 in a molar amount lower than that of the starting hydroquinone.
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- REACTION OF MONOSUBSTITUTED AROMATIC HYDROCARBONS WITH STYRENE
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1,1-Phenylarylethanes were obtained by the reaction of styrene with some monosubstituted aromatic hydrocarbons in the presence of titanium tetrachloride.It was established that electron-donating substituents have an effect on the yield of the arylalkylation products.
- Grushin, A. I.,Grigor'ev, V. V.,Prokof'ev, K. V.,Kozlova, N. M.
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p. 1991 - 1993
(2007/10/02)
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- ON THE 1,6-ADDITION OF ALKYLALUMINIUM COMPOUNDS TO para-QUINONES
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Ethyl, n-butyl and i-butylaluminium dichlorides undergo 1,6-addition to a conjugated bond system O=C-C=C-C=O of para-quinones.Methylaluminium dichloride is inactive in this addition, and triethylaluminium gives low yields.The reactivities of the quinones vary with their electron affinities, and the highest yields of 1,6-addition are obtained in the reactions of chlorine derivatives of 1,4-benzoquinone.The results are discussed in terms of a radical mechanism involving a homolytic cleavage of the Al-C bond in the donor-acceptor complex formed between the reactants followed by combination of alkyl radicals and aluminium derivatives of semiquinone within a cage.The stable donor-acceptor complexes and aluminium derivative of semiquinone were isolated and characterized from the reactions of aluminium trichloride with 2,3,5,6-tetramethyl-1,4-benzoquinone and 2,3,5,6-tetrachloro-1,4-benzoquinone, respectively.
- Florjanczyk, Zbigniew,Szymanska-Zachara, Ewa
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p. 127 - 138
(2007/10/02)
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- LIQUID CRYSTALLINE PROPERTIES OF 4-N-ALKOXYPHENYL 4-NITROBENZOATES.
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Twelve 4-alkoxyphenyl esters of 4-nitrobenzoic acid were synthesized. The mesophases were identified and the transition temperatures and enthalpies determined. The above series shows considerable similarity to the reverse analogues, i. e. , the 4-nitro-phenyl 4-n-alkoxybenzoates.
- Galewski,Sobczyk
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