- Multifunctional Luminescence Sensors Assembled with Lanthanide and a Cyclotriveratrylene-Based Ligand
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By using a cyclotriveratrylene-based ligand 5,12,19-trimethoxy-6,13,20-tricarboxy-methoxy-cyclotriveratrylene (H3L), four lanthanide-based compounds, Eu(L)(DMF)2 (1), Tb(L)(DMF)2 (2), Gd(L)(DMF)2 (3), and Yb(L)(
- Ma, Li,Zhang, Qin,Wu, Hua,Yang, Jin,Liu, Ying-Ying,Ma, Jian-Fang
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- Design and Synthesis of Novel 4-Hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one Derivatives for Use as Herbicides and Evaluation of Their Mode of Action
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In order to develop a novel herbicide containing the β-triketone motif, a series of 4-hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one derivatives were designed and synthesized. The bioassay results showed that compound II15 had good pre-emergent herbicidal activity even at a dosage of 187.5 g ha-1. Moreover, compound II15 showed a broader spectrum of weed control when compared with a commercial herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), and displayed good crop safety to Triticum aestivum L. and Zea mays Linn. when applied at 375 g ha-1 under pre-emergence conditions, which indicated its great potential as a herbicide. More importantly, studying the molecular mode of action of compound II15 revealed that the novel triketone structure is a proherbicide of its corresponding phenoxyacetic acid auxin herbicide, which has a herbicidal mechanism similar to that of 2,4-D. The present work indicates that the 4-hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one motif may be a potential lead structure for further development of novel auxin-type herbicides.
- Lei, Kang,Li, Pan,Yang, Xue-Fang,Wang, Shi-Ben,Wang, Xue-Kun,Hua, Xue-Wen,Sun, Bin,Ji, Lu-Sha,Xu, Xiao-Hua
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p. 10489 - 10497
(2019/10/02)
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- Highly effective C-C bond cleavage of lignin model compounds
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A highly effective method is developed for the C-C bond cleavage of lignin model compounds. The inert Cα-Cβ or Cα-Cphenyl bond of oxidized lignin model compounds was successfully converted to an active ester bond through the classic organic name reaction, Baeyer-Villiger (BV) oxidation, and thus acetal esters and aryl esters were produced in high yields (up to 99%) at room temperature. Next, K2CO3 catalyzed the alcoholysis of the resulting ester products at 45 °C, affording various useful chemical platforms in excellent yields (up to 99%), such as phenols and multifunctional esters. This method uses commercially available reagents, is transition-metal free and simple, but highly effective, and involves mild reaction conditions.
- Wang, Yinling,Wang, Qianyi,He, Jianghua,Zhang, Yuetao
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supporting information
p. 3135 - 3141
(2017/07/24)
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- Ytterbium complex of hydroxyl-substituted cyclotriveratrylene and preparation method thereof
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The invention discloses an ytterbium complex of hydroxyl-substituted cyclotriveratrylene. The structural formula of the ytterbium complex is Yb(L)(DMF)(H2O). The ytterbium complex is synthesized through a solvothermal method by coordinating with a rare ea
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Paragraph 0010
(2017/08/31)
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- SELECTIVE CARBON-CARBON BOND CLEAVAGE BY EARTH ABUNDANT VANADIUM COMPOUNDS UNDER VISIBLE LIGHT PHOTOCATALYSIS
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Provided herein a vanadium(V) complex of formula I, where R1 to R8 are as defined herein. Also provided herein are reactions making use of the vanadium(V) complex of formula I, such as selective sp3-sp3 carbon-carbon bond cleavage under visible light photocatalysis and photodegradation of lignin.
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- Solar photochemical oxidation of alcohols using catalytic hydroquinone and copper nanoparticles under oxygen: Oxidative cleavage of lignin models
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Alcohols are converted into to their corresponding carbonyl compounds using catalytic amounts of 1,4-hydroquinone with a copper nanoparticle electron transfer mediator with oxygen as the terminal oxidant in acetone as solvent under visible light irradiation. These conditions employing biorenewable hydroquinone as reagent were developed from initial experiments using stoichiometric amounts of 1,4-benzoquinone as oxidant. A range of benzylic and aliphatic primary and secondary alcohols are oxidized, affording the corresponding aldehydes or ketones in moderate to excellent yields. The methodology is also applicable to the oxidative degradation of lignin model compounds that undergo C-C bond cleavage to give simple aromatic compounds.
- Mitchell, Lorna J.,Moody, Christopher J.
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p. 11091 - 11100
(2015/01/08)
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- Catalyst-free photoredox addition-cyclisations: Exploitation of natural synergy between aryl acetic acids and maleimide
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Suitably functionalised carboxylic acids undergo a previously unknown photoredox reaction when irradiated with UVA in the presence of maleimide. Maleimide was found to synergistically act as a radical generating photoxidant and as a radical acceptor, negating the need for an extrinsic photoredox catalyst. Modest to excellent yields of the product chromenopyrroledione, thiochromenopyrroledione and pyrroloquinolinedione derivatives were obtained in thirteen preparative photolyses. In situ NMR spectroscopy was used to study each reaction. Reactant decay and product build-up were monitored, enabling reaction profiles to be plotted. A plausible mechanism, whereby photo-excited maleimide acts as an oxidant to generate a radical ion pair, has been postulated and is supported by UV/Vis. spectroscopy and DFT computations. The radical-cation reactive intermediates were also characterised in solution by EPR spectroscopy. UVA photolyses of aryloxy-, arylthio- and arylamino-acetic acids with maleimide yield oxa-, thia- and aza-tricyclo pyrroledione derivatives in the absence of a photoredox catalyst (see scheme). An intriguing mechanism has been proposed and has been supported and supplemented by NMR monitoring experiments, DFT computations and UV/Vis and EPR spectroscopy.
- Manley, David W.,Mills, Andrew,O'Rourke, Christopher,Slawin, Alexandra M. Z.,Walton, John C.
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supporting information
p. 5492 - 5500
(2014/05/20)
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- The discovery of N -[5-(4-bromophenyl)-6-[2-[(5-bromo-2-pyrimidinyl)oxy] ethoxy]-4-pyrimidinyl]- N ′-propylsulfamide (macitentan), an orally active, potent dual endothelin receptor antagonist
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Starting from the structure of bosentan (1), we embarked on a medicinal chemistry program aiming at the identification of novel potent dual endothelin receptor antagonists with high oral efficacy. This led to the discovery of a novel series of alkyl sulfamide substituted pyrimidines. Among these, compound 17 (macitentan, ACT-064992) emerged as particularly interesting as it is a potent inhibitor of ETA with significant affinity for the ET B receptor and shows excellent pharmacokinetic properties and high in vivo efficacy in hypertensive Dahl salt-sensitive rats. Compound 17 successfully completed a long-term phase III clinical trial for pulmonary arterial hypertension.
- Bolli, Martin H.,Boss, Christoph,Binkert, Christoph,Buchmann, Stephan,Bur, Daniel,Hess, Patrick,Iglarz, Marc,Meyer, Solange,Rein, Josiane,Rey, Markus,Treiber, Alexander,Clozel, Martine,Fischli, Walter,Weller, Thomas
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supporting information
p. 7849 - 7861
(2012/10/29)
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- Hydrogenolysis of β-O-4 lignin model dimers by a ruthenium-xantphos catalyst
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Hydrogenolysis reactions of so-called lignin model dimers using a Ru-xantphos catalyst are presented (xantphos = 4,5-bis(diphenylphosphino)-9,9- dimethylxanthene). For example, of some nine models studied, the alcohol, 2-(2-methoxyphenoxy)-1-phenylethanol (1), with 5 mol% Ru(H)2(CO) (PPh3)(xantphos) (18) in toluene-d8 at 135 °C for 20 h under N2, gives in ~95% yield the C-O cleavage hydrogenolysis products, acetophenone (14) and guaiacol (17), and a small amount (1H NMR spectroscopy. The in situ Ru(H)2(CO)(PPh 3)3/xantphos system gives similar findings, confirming a recent report (J. M. Nichols et al., J. Am. Chem. Soc., 2010, 132, 12554). The active catalyst is formulated 'for convenience' as 'Ru(CO)(xantphos)'. The hydrogenolysis mechanism proceeds by initial dehydrogenation to give the ketone 4, which then undergoes hydrogenolysis of the C-O bond to give 14 and 17. Hydrogenolysis of 4 to 14 and 17 also occurs using the Ru catalyst under 1 atm H2; in contrast, use of 3-hydroxy-2-(2-methoxyphenoxy)-1-phenyl-1- propanone (7), for example, where the CH2 of 4 has been changed to CHCH2OH, gives a low yield (≤15%) of hydrogenolysis products. Similarly, the diol substrate, 2-(2-methoxyphenoxy)-1-phenyl-1,3-propanediol (9), gives low yields of hydrogenolysis products. These low yields are due to formation of the catalytically inactive complexes Ru(CO)(xantphos)[C(O)C(OC 6H4OMe)C(Ph)O] (20) and/or Ru(CO)(xantphos)[C(O)CHC(Ph)O] (21), where the organic fragments result from dehydrogenation of CH 2OH moieties in 7 and 9. Trace amounts of Ru(CO)(xantphos)(OC 6H4O), a catecholate complex, are isolated from the reaction of 18 with 1. Improved syntheses of 18 and lignin models are also presented.
- Wu, Adam,Patrick, Brian O.,Chung, Enoch,James, Brian R.
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p. 11093 - 11106
(2012/10/30)
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- Aryloxyacetic esters structurally related to α-Asarone as potential antifungal agents
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A series of aryloxyacetic ester analogues 8-13 was synthesized based on the potential pharmacophores of the antifungal agents α-Asarone (1) and 2-5. Their antifungal activity was tested in vitro for their growth inhibitory activities against pathogenic fungi. The in vitro antifungal evaluation of these alkyl and aryl esters shows that derivatives 10 displayed the highest antifungal and fungicidal activities against Cryptococcus neoformans and C. gattii. These results support the idea that the phenoxyacetic frame is a potent pharmacophore for the design of potential antifungal drugs. Graphical Abstract: [Figure not available: see fulltext.]
- Jimenez, Fabiola,Cruz, Maria Del Carmen,Zuniga, Clara,Martinez, Maria A.,Chamorro, German,Diaz, Francisco,Tamariz, Joaquin
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experimental part
p. 33 - 57
(2010/10/20)
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- Applicability of Hammett Equation to Kinetics of Acid-catalysed Esterification of ortho-Substituted Phenoxyacetic, Phenylmercaptoacetic and Phenylsulphonylacetic Acids by Methanol
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Correlation analysis of the title rate data shows that the steric effects of ortho-substituents are absent at the reaction centre.
- Baliah, V.,Gurumurthy, R.
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p. 257 - 258
(2007/10/02)
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- Applicability of Hammett Equation to Insulated Systems - Kinetics of Alkaline Hydrolysis of ortho-Substituted Methyl Phenoxyacetates
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Kinetics of alkaline hydrolysis of some ortho-substituted methyl phenoxyacetates in methanol-water (85percent wt/wt) at 10 deg, 15 deg and 20 deg are reported.The application of Taft's steric energy relationship shows that the reaction is not susceptible
- Gurumurthy, R.,Balakrishnan, N.
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p. 1114 - 1115
(2007/10/02)
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