- Discovery, Biocatalytic Exploration and Structural Analysis of a 4-Ethylphenol Oxidase from Gulosibacter chungangensis
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The vanillyl-alcohol oxidase (VAO) family is a rich source of biocatalysts for the oxidative bioconversion of phenolic compounds. Through genome mining and sequence comparisons, we found that several family members lack a generally conserved catalytic aspartate. This finding led us to study a VAO-homolog featuring a glutamate residue in place of the common aspartate. This 4-ethylphenol oxidase from Gulosibacter chungangensis (Gc4EO) shares 42 % sequence identity with VAO from Penicillium simplicissimum, contains the same 8α-N3-histidyl-bound FAD and uses oxygen as electron acceptor. However, Gc4EO features a distinct substrate scope and product specificity as it is primarily effective in the dehydrogenation of para-substituted phenols with little generation of hydroxylated products. The three-dimensional structure shows that the characteristic glutamate side chain creates a closely packed environment that may limit water accessibility and thereby protect from hydroxylation. With its high thermal stability, well defined structural properties and high expression yields, Gc4EO may become a catalyst of choice for the specific dehydrogenation of phenolic compounds bearing small substituents.
- Alvigini, Laura,Fraaije, Marco W.,Gran-Scheuch, Alejandro,Guo, Yiming,Mattevi, Andrea,Saifuddin, Mohammad,Trajkovic, Milos
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p. 3225 - 3233
(2021/10/04)
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- Non-plasmonic Ni nanoparticles catalyzed visible light selective hydrogenolysis of aryl ethers in lignin under mild conditions
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Light-driven catalysis on catalytically versatile group VIII metals, which has been widely used in thermal catalysis, holds great potential in solar-to-chemical conversion. We report a novel photocatalysis process for the selective hydrogenolysis of aryl ethers in lignin on a heterogeneous catalyst of non-precious Ni nanoparticles supported on ZrO2. Three aryl ether bonds in lignin were successfully cleaved under mild conditions with excellent conversion and good to excellent selectivity under visible light irradiation. We also used solar irradiation to demonstrate a significant reduction in the total energy consumption. The light irradiation excited interband transitions in Ni nanoparticles and the resultant energetic electrons enhanced the activity of reductive cleavage of the aryl ethers. Its application potential was illustrated by the depolymerization of dealkaline lignin to give a total monomer yield of 9.84 wt% with vanillin, guaiacol, and apocynin as the three major products.
- Baeyens, Jan,Li, Peifeng,Ouyang, Yixuan,Sarina, Sarina,Su, Haijia,Xiao, Gang,Zhao, Yilin,Zhu, Huai-Yong
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supporting information
p. 7780 - 7789
(2021/10/12)
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- AN IMPROVED AND COMMERCIALLY VIABLE PROCESS FOR PREPARATION OF ARYL KETONES
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The present disclosure provides a process for preparing an aryl ketone of Formula I, comprising reacting a substituted benzene of Formula II with a carboxylic acid of formula IIIa and/or a carboxylic anhydride of formula IIIb in presence of an alkyl sulfonic acid acting as catalyst cum solvent/contacting medium. I, II, IIIa, IIIb, wherein, R1, R2, R3 and R4 are as defined in the description.
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Paragraph 0085; 0087
(2020/09/12)
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- A convenient synthetic approach to dioncoquinone B and related compounds
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A total synthesis of dioncoquinone B and related compounds, including ancistroquinones B, C and malvon A, is presented. The strategy is based on available reagents and can be used as a preparative synthesis of a number of natural and synthetic biologically active (3-alkyl)-2,7,8-di(tri)methoxy(hydroxy)-1,4-naphthoquinones.
- Khmelevskaya, Ekaterina A.,Pelageev, Dmitry N.
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supporting information
p. 1022 - 1024
(2019/03/13)
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- Ethacrynic acid as a lead structure for the development of potent urease inhibitors
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Ethacrynic acid and a series of its analogues were synthesized and subsequently evaluated for their inhibitory effect on jack bean urease. Ethacrynic acid showed, even at low concentrations, very potent inhibitory activity against the enzyme. For ethacrynic acid, the inhibition potential increased with increasing preincubation time of ethacrynic acid and enzyme, whereas for some other compounds a higher preincubation time lead to a significant reduction of their activity. We could demonstrate that the α,β-unsaturated carbonyl unit of our compounds is mandatory to inhibit the enzyme, possibly due to its ability to bind to cysteine residues in the active site of the jack bean urease.
- Janser, Ingo,Vortolomei, Caitlyn M.,Meka, Ranjith K.,Walsh, Courtney A.,Janser, Romy F.J.
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p. 660 - 664
(2013/08/15)
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- NOVEL ARYLALKENE DERIVATIVES AND USE THEREOF AS SELECTIVE ESTROGEN RECEPTOR MODULATORS
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The invention provides novel ethylene derivatives represented by Formula I, which may be used as selective estrogen receptor modulators (SERMs) and useful in the prophylaxis and/or treatment of estrogen-dependent conditions or conditions.
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- Ethacrynic acid analogues lacking the α,β-unsaturated carbonyl unit-Potential anti-metastatic drugs
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A series of ethacrynic acid analogues, lacking the α,β-unsaturated carbonyl unit, was synthesized and subsequently evaluated for their ability to inhibit the migration of human breast cancer cells, MCF-7/AZ. Several of the analogues were already active in the low micromolar range, whereas ethacrynic acid itself shows no potential to inhibit the migration of these cancer cells. Preliminary studies show that the presence of one or more methoxy groups at the phenyl ring of ethacrynic acid is important in order for the ethacrynic acid analogues to demonstrate an inhibitory effect on the migration.
- Janser, Romy F.J.,Meka, Ranjith K.,Bryant, Zack E.,Adogla, Enoch A.,Vogel, Elizabeth K.,Wharton, Jaimie L.,Tilley, Cynthia M.,Kaminski, Catherine N.,Ferrey, Seth L.,Van slambrouck, Severine,Steelant, Wim F.A.,Janser, Ingo
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experimental part
p. 1848 - 1850
(2010/07/06)
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- Microwave- and ultrasound-assisted semisynthesis of natural methoxylated propiophenones from isomeric mixture of phenylpropenes in minutes
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A rapid and practical semisynthesis of natural methoxylated propiophenones (3a-3f) is realized by reacting stereo- and regio-isomeric mixture of phenylpropenes (1a-1f) with a catalytic amount of palladium chloride - sodium formate in formic acid, methanol, and water (2:1:2) into single product phenylpropanes (2a-2f) followed by its oxidation with 2,3-dichloro-5,6- dicyanobenzoquinone (DDQ) in wet dioxane, containing a few drops of formic acid. Conventional, ultrasound, and microwave heating were compared through these studies.
- Joshi, Bhupendra P.,Sharma, Anuj,Sinha, Arun K.
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p. 1826 - 1832
(2007/10/03)
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- Methoxyphenols from burning of Scandinavian forest plant materials
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Semivolatile compounds in smoke from gram-scale incomplete burning of plant materials were assessed by gas chromatography and mass spectrometry. Gas syringe sampling was shown to be adequate by comparison with adsorbent sampling. Methoxyphenols as well as 1,6-anhydroglucose were released in amounts as large as 10 mg kg-1 of dry biomass at 90% combustion efficiency. Wood, twigs, bark and needles from the conifers Norway spruce and Scots pine emitted 12 reported 2-methoxyphenols in similar proportions. Grass, heather and birchwood released the same 2-methoxyphenols but also the corresponding 2,6-dimethoxyphenols which are characteristic of angiosperms. The methoxyphenols are formed from lignin and differ in structure by the group in para position relative to the phenolic OH group. Prominent phenols were those with trans-l-propenyl and ethenyl groups in that position. Vanillin, 4- hydroxy-3-methoxybenzaldehyde, was a prominent carbonyl compound from the conifer materials. (C) 2000 Elsevier Science Ltd.
- Kjaellstrand, Jennica,Ramnaes, Olle,Petersson, Goeran
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p. 735 - 741
(2007/10/03)
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- Synthesis of Apocynin, a Choleretic Constituent of Picrorhiza kurroa and Its Homologues
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Apocynin (4-hydroxy-3-methoxyacetophenone) and a few of its side chain homologues have been synthesized by a simple two-step procedure.The key step in the synthesis involves Grignard reaction between vanillin acetate and different haloalkanes.The carbinols thus generated have been dehydrogenated to the desired compounds by stirring with DDQ in benzene.The synthesised compounds show consistent choleretic activity in experimental animals.
- Suri, O. P.,Bindra, R. S.,Satti, N. K.,Khajuria, R. K.
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p. 587 - 588
(2007/10/02)
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