- Four interpenetrating hydrogen-bonded three-dimensional networks in divanillin
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The crystal structure of divainillin (systematic name: 6,6′-dihydroxy-5,5′-dimethoxy-[1,1′-biphenyl]-3,3′-dicarbaldehyde), C16H14O6, was determined from laboratory powder X-ray diffraction data using the software EXPO2013 (direct methods) and WinPSSP (direct-space approach). Divanillin molecules crystallize in the orthorhombic space group Pba2 (No. 32), with two molecules per unit cell (Z′ =). Each divanillin molecule, with twofold symmetry, is linked through strong alcohol–aldehyde hydrogen bonds to four equivalent molecules, defining a three-dimensional hydrogen-bonding network, with rings made up of six divanillin units (a diamond-like arrangement). Each molecule is also connected through π–π interactions to a translation-equivalent molecule along c. Four consecutive molecules stacked along [001] belong to four different three-dimensional hydrogen-bonding networks defining a quadruple array of interpenetrating networks. This complex hydrogen-bonding array is proposed as an explanation for the aging process experienced by divanillin powders.
- Imer, Marcos R.,Aldabalde, Virginia,Pagola, Silvina,Streek, Jacco van de,Suescun, Leopoldo
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- The early oxidative biodegradation steps of residual kraft lignin models with laccase
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A number of model compounds resembling the fundamental bonding patterns of residual kraft lignin, including a series of stilbenes, were incubated with laccase from Trametes versicolor in the presence and absence of delignification 'mediators' ABTS and HBT. The condensed kraft lignin model compounds seem to undergo initial degradation by laccase mainly via benzylic oxidation, demethylation and hydroxylation reactions. Phenolic 5-5', diphenylmethane and α-5 lignin models were found to be degraded mainly via side-chain oxidation reactions. Among the models studied, a phenolic stilbene was found to be the most reactive, yielding several products showing side-chain oxidation/transposition, demethoxylation and hydroxylation reactions. Non-phenolic 5-5', diphenylmethane and stilbene model compounds were found unreactive even in the presence of the laccase-mediator system. Copyright (C) 1997 Elsevier Science Ltd.
- Crestini, Claudia,Argyropoulos, Dimitris S.
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- Electrochemical synthesis of biobased polymers and polymer building blocks from vanillin
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Vanillin, one of the few biobased aromatic compounds available on an industrial level, is an attractive candidate for the synthesis of biobased polymers and polymer building blocks. This study presents a detailed investigation of the reductive electrochemical coupling process by pinacolization of vanillin and divanillin in an electrochemical H-type cell setup to the polymer building block hydrovanilloin and to polyvanillin, respectively. Therein, different cathode materials are screened by linear sweep voltammetry for their capability and activity of hydrodimerization of phenolic aromatic aldehydes in alkaline aqueous media. Product distributions and faradaic efficiencies of the electrochemical vanillin reduction are investigated in bulk electrolysis experiments. Dependencies on electrochemical parameters such as current densities, applied charges and cathode materials are studied. Furthermore, the polyvanillin synthesis from divanillin is also investigated by bulk electrolysis experiments. The effects of selected electrochemical parameters (current density, applied charge and electrode material) on yield and structural features (weight-average molecular weight (MW), number-average molecular weight (MN), polydispersity (MW/MN)) measured by size exclusion chromatography of the obtained polyvanillin were evaluated. Structural features of isolated polyvanillin were determined by 2D-NMR (HSQC,13C/1H) analyses and by31P-NMR analyses afterin situlabeling with Cl-TMDP and possible pathways for their generation are discussed. These two promising electro-synthetic processes studied are free of hazardous materials and reagents and highlight the contributions of preparative electrochemistry to green chemistry and further pave the way toward the application of electrochemistry in the synthesis of biobased building blocks and polymers.
- Kunkel, Robin,Schmidt, Volkmar M.,Cremers, Carsten,Müller, Dominik,Schmiedl, Detlef,Tübke, Jens
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- Adsorption and anti-corrosion characteristics of vanillin Schiff bases on mild steel in 1 M HCl: Experimental and theoretical study
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Herein, two Schiff base derivatives of vanillin and divanillin with 2-picolylamine, namely, 2-methoxy-4-((pyridin-2-ylmethylimino)methyl)phenol (compound A) and 3,3′-dimethoxy-5,5′-bis-((pyridin-2-ylmethylimino)methyl)-[1,1′-biphenyl]-2,2′-diol (compound B), respectively, were synthesized. Additionally, their adsorption characteristics and corrosion inhibition behavior were compared for mild steel in 1 M HCl using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss methods. Compound B was found to impart a better anti-corrosive effect (around 95% inhibition efficiency at 313 K) than compound A. The inhibitors act as effective mixed-type inhibitors and exhibit Langmuir-type adsorption behaviour. The kinetic-thermodynamic parameters together with the data obtained from density functional theory (DFT) and molecular dynamics (MD) simulations illustrate the mechanism of corrosion and mode of adsorption of both inhibitors on the metal surface. The better corrosion mitigation propensity of the dimeric form of the inhibitor (compound B) over the monomeric form (compound A) was tested experimentally and explained according to the theoretical data.
- Banerjee, Priyabrata,Saha, Sourav Kr.,Satpati, Sanjoy,Suhasaria, Aditya,Sukul, Dipankar
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- 5,5′-bis-vanillin derivatives as discriminating sensors for trivalent cations
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Abstract Several bis-vanillin derivatives containing semicarbazone moieties have been prepared and used in discriminating trivalent cations. The prepared probes are readily obtained and they are usually highly crystalline. Depending on the ligand and the studied cations, quenching, enhancement or no changes in the fluorescence spectrum were observed. Using a series of the prepared ligands allows distinguishing between Fe3+, Cr3+ and Al3+. Detection limits and selectivity in front of divalent cations have been evaluated.
- Costero, Ana M.,Gil, Salvador,Parra, Margarita,Mancini, Pedro M.E.,Kneeteman, María N.,Quindt, Matías I.
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- Induction of axial chirality in divanillin by interaction with bovine serum albumin
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Vanillin is a plant secondary metabolite and has numerous beneficial health applications. Divanillin is the homodimer of vanillin and used as a taste enhancer compound and also a promissory anticancer drug. Here, divanillin was synthesized and studied in the context of its interaction with bovine serum albumin (BSA). We found that divanillin acquires axial chirality when complexed with BSA. This chiroptical property was demonstrated by a strong induced circular dichroism (ICD) signal. In agreement with this finding, the association constant between BSA and divanillin (3.3 × 105 mol-1L) was higher compared to its precursor vanillin (7.3 × 104 mol-1L). The ICD signal was used for evaluation of the association constant, demonstration of the reversibility of the interaction and determination of the binding site, revealing that divanillin has preference for Sudlow's site I in BSA. This property was confirmed by displacement of the fluorescent markers warfarin (site I) and dansyl-L-proline (site II). Molecular docking simulation confirmed the higher affinity of divanillin to site I. The highest scored conformation obtained by docking (dihedral angle 242°) was used for calculation of the circular dichroism spectrum of divanillin using Time-Dependent Density Functional Theory (TDDFT). The theoretical spectrum showed good similarity with the experimental ICD. In summary, we have demonstrated that by interacting with the chiral cavities in BSA, divanillin became a atropos biphenyl, i.e., the free rotation around the single bound that links the aromatic rings was impeded. This phenomenon can be explained considering the interactions of divanillin with amino acid residues in the binding site of the protein. This chiroptical property can be very useful for studying the effects of divanillin in biological systems. Considering the potential pharmacological application of divanillin, these findings will be helpful for researchers interested in the pharmacological properties of this compound.
- Venturini, Diego,De Souza, Aguinaldo Robinson,Caracelli, Ignez,Morgon, Nelson Henrique,Da Silva-Filho, Luiz Carlos,Ximenes, Valdecir Farias
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- Evaluation of antioxidant activity of vanillin by using multiple antioxidant assays
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Background: Vanillin, a compound widely used in foods, beverages, cosmetics and drugs, has been reported to exhibit multifunctional effects such as antimutagenic, antiangiogenetic, anti-colitis, anti-sickling, and antianalgesic effects. However, results of studies on the antioxidant activity of vanillin are not consistent. Methods: We systematically evaluated the antioxidant activity of vanillin using multiple assay systems. DPPH radical-, galvinoxyl radical-, and ABTS+-scavenging assays, ORAC assay and an oxidative hemolysis inhibition assay (OxHLIA) were used for determining the antioxidant activity. Results and conclusion: Vanillin showed stronger activity than did ascorbic acid and Trolox in the ABTS+-scavenging assay but showed no activity in the DPPH radical- and galvinoxyl radical-scavenging assays. Vanillin showed much stronger antioxidant activity than did ascorbic acid and Trolox in the ORAC assay and OxHLIA. In the ABTS+-scavenging assay, ORAC assay and OxHLIA, vanillin reacted with radicals via a self-dimerization mechanism. The dimerization contributed to the high reaction stoichiometry against ABTS + and AAPH-derived radicals to result in the strong effect of vanillin. Oral administration of vanillin to mice increased the vanillin concentration and the antioxidant activity in plasma. These data suggested that antioxidant activity of vanillin might be more beneficial than has been thought for daily health care. General significance: Based on the results of the present study, we propose the addition of antioxidant capacity to the multifunctionality of vanillin.
- Tai, Akihiro,Sawano, Takeshi,Yazama, Futoshi,Ito, Hideyuki
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- Homodimers of Vanillin and Apocynin Decrease the Metastatic Potential of Human Cancer Cells by Inhibiting the FAK/PI3K/Akt Signaling Pathway
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The spread of cancer cells to distant organs, in a process called metastasis, is the main factor that contributes to most death in cancer patients. Vanillin, the vanilla flavoring agent, has been shown to suppress metastasis in a mouse model. Here, we evaluated the antimetastatic potential of the food additive divanillin, the homodimer of vanillin, and their structurally related compounds, apocynin and diapocynin, in hepatocellular carcinoma cells. The Transwell invasion assay showed that the dimeric forms exhibited a potency higher than those of vanillin and apocynin in inhibiting invasion, with IC50 values of 23.3 ± 7.4 to 41.3 ± 4.2 μM for the dimers, which are 26-34-fold lower than IC50 values of vanillin and apocynin (p 0.05). Both monomeric and dimeric forms target regulation of the invasion process by inhibiting phosphorylation of FAK and Akt. Molecular docking studies suggested that the dimers should bind more tightly than vanillin and apocynin to the Y397 pocket of the FAK FERM domain. Thus, the food additive divanillin has antimetastatic potential greater than that of the flavoring agent vanillin.
- Jantaree, Phatcharida,Lirdprapamongkol, Kriengsak,Kaewsri, Wilailak,Thongsornkleeb, Charnsak,Choowongkomon, Kiattawee,Atjanasuppat, Korakot,Ruchirawat, Somsak,Svasti, Jisnuson
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- Antiatherogenic effect of bisvanillyl-hydralazone, a new hydralazine derivative with antioxidant, carbonyl scavenger, and antiapoptotic properties
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Reactive oxygen species (ROS) generated within the vascular wall trigger low-density lipoprotein (LDL) oxidation, lipid peroxidation, and carbonyl stress that are involved in atherogenesis. We recently reported that the antihypertensive drug, hydralazine, exhibits carbonyl scavenger and antiatherogenic properties, but only moderate antioxidant activity, so that high concentrations are required for inhibiting LDL oxidation. We aimed to develop agents sharing both antioxidant and carbonyl scavenger properties. We have synthesized a new hydralazine derivative, the bisvanillyl-hydralazone (BVH). BVH strongly inhibited LDL oxidation induced by copper and by human endothelial cells (HMEC-1), and prevented the formation of macrophagic foam cells. BVH reduced both the extracellular generation of ROS (superoxide anion and hydrogen peroxide) induced by oxidized LDL (oxLDL), as well as intracellular oxidative stress and proteasome activation, NFkappaB activation, and oxLDL-mediated proinflammatory signaling. In parallel, BVH prevented the carbonyl stress induced by oxLDL on cellular proteins, and blocked the apoptotic cascade as assessed by the inhibition of Bid cleavage, cytochrome C release, and DEVDase activation. Lastly, BVH prevented atherogenesis and carbonyl stress in apoE -/- mice. In conclusion, BVH is the prototype of a new class of antioxidant and carbonyl scavenger agents designed for new therapeutical approaches in atherosclerosis. Mary Ann Liebert, Inc.
- Bouguerne, Benaissa,Belkheiri, Nadji,Bedos-Belval, Florence,Vindis, Cecile,Uchida, Koji,Duran, Hubert,Grazide, Marie-Helene,Baltas, Michel,Salvayre, Robert,Negre-Salvayre, Anne
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- Selective laccase-catalyzed dimerization of phenolic compounds derived from lignin: Towards original symmetrical bio-based (bis) aromatic monomers
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A laccase-catalyzed process was developed to prepare, selectively, in high yield, dimers of lignin-based phenolic compounds without any purification. The influence of experimental parameters such as laccase loading, nature of solvent and the presence of oxygen on the conversion of vanillin was investigated. After the dimerization, the product obtained as a precipitate is filtered off and the solution containing the enzyme can be re-used several times, which improves the process economics. A phenolic-substrate screening reveals that such process enables to dimerize regioselectively, six ortho-methoxy-para-substituted phenols (vanillin, 4-hydroxy-3-methoxybenzonitrile, acetovanillon, methyl vanillate, 2-methoxy-4-methylphenol, and eugenol) with yields ranging from 87% to 96% and one ortho-disubstituted phenol (2,6-dimethoxyphenol) with 80% yield.
- Llevot, Audery,Grau, Etienne,Carlotti, Stéphane,Grelier, Stéphane,Cramail, Henri
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- Convenient preparation and quantification of 5,5′-diferulic acid
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5,5′-Diferulic acid (5,5′-DFA), which is one of the cross-linking residues in plant cell walls, was prepared by using a facile procedure. The phenol oxidation of vanillin with Fe Cl3 gave divanillin, which was further devoted to a Perkin reaction to give the desired product. It was found on 13C-NMR that the chemical shift of C-5 of ferulic acid (FA) clearly shifted downfield, when this carbon is quaternarized by the oxidative dimerizaton to 5,5′-DFA, while those of other carbons of 5,5′-DFA are fundamentally same as those of FA. Also prepared was [9,9′-13C2]-5,5′-DFA, which was proved to be a good internal standard on GC-MS quantification of endogenous 5,5′-DFA from plant tissues.
- Yamamoto, Hirotaka,Hoshino, Tsutomu,Uchiyama, Takeo
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- Compositional analysis of organosolv poplar lignin by using high-performance liquid chromatography/high-resolution multi-stage tandem mass spectrometry
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Organosolv treatment is an efficient and environmentally friendly process to degrade lignin into small compounds. The capability of characterizing the individual compounds in the complex mixtures formed upon organosolv treatment is essential for the optimization of the further lignin conversion processes and for the rational genetic engineering of plants used to produce lignin in order to improve lignin properties. In this study, an organosolv poplar lignin sample was initially analyzed by high-resolution mass spectrometry coupled with negative-ion mode electrospray ionization ((?)ESI HRMS). Lignin monomers and dimers were found to constitute the majority of the compounds in the organosolv lignin sample. Larger lignin oligomers, such as trimers and tetramers, and some not lignin-related compounds, were also detected. A high-performance liquid chromatograph/linear quadrupole ion trap/orbitrap mass spectrometer capable of multi-stage high-resolution tandem mass spectrometry experiments (HRMSn), equipped with an (?)ESI source (HPLC/(?)ESI HRMSn), was employed to separate the unknown compounds in the organosolv mixture and to obtain structural information for the deprotonated compoundsviacollision-activated dissociation (CAD) HRMSnexperiments. To improve the understanding of the CAD behavior of deprotonated lignin-related compounds, 16 deprotonated model compounds with different functionalities and linkage types were examined. This approach enabled the assignment of likely structures for several lignin monomers, dimers, trimers, and tetramers, and some not lignin-related compounds, most likely fatty acids. Based on the proposed structures, compounds in the organosolv lignin sample contain β-O-4, 5-5, β-5, and possibly also 4-O-5 linkages. Most compounds contain G- and S-monomeric units although a small amount of H-units were also detected.
- Zhang, Jifa,Jiang, Yuan,Easterling, Leah F.,Anstner, Anton,Li, Wanru,Alzarieni, Kawthar Z.,Dong, Xueming,Bozell, Joseph,Kentt?maa, Hilkka I.
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supporting information
p. 983 - 1000
(2021/02/09)
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- A selective colorimetric chemosensor for detection of Cu(II) ions in aqueous samples
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In this work we report a selective colorimetric chemosensor (S) for Cu2+ ion detection in aqueous media. It has been synthesized by a condensation reaction between 1-hydrazinophtalazine and 6,60-dihydroxy-5,50dimethoxy-(1,10-biphenyl)-3,30-dicarbaldehyde. The interaction between S and Cu2+ was studied and the results showed a bathochromic shift at 420 nm in UV–Vis spectra. The absorbance enhancement of S was attributed to complex formation with Cu2+ by 2:1 stoichiometry. The proposed analytical method can be applied to Cu2+ quantification with a linear range covering from 5.0 to 315.8 μM, and can be used to routinely analyze Cu2+ in environmental aqueous samples with satisfactory results.
- Ferretti, Cristián Alejandro,Guntero, Vanina Alejandra,Gutierrez, Leandro Gabriel,Kneeteman, María Nelida,Noriega, Pablo Javier
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- Hydrothermal polymerization towards fully biobased polyazomethines
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Microwave assisted polycondensation for the synthesis of (partially) biobased polyazomethines in water (hydrothermal polymerization) was investigated for the first time in this study. The polyazomethines prepared via this environmentally friendly and simple method show comparable characteristics as the polymers prepared via traditional methods in organic solvents.
- Bernaerts, Katrien V.,Gebben, Bert,Li, Guotai,Meeusen-Wierts, Monique H. M.,Noordijk, Jurrie,Oude Lohuis, Petra A. M.,Schotman, Anton H. M.,Yu, Kui
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supporting information
p. 9194 - 9197
(2020/08/26)
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- Efficient and sustainable laccase-catalyzed iodination of: P -substituted phenols using KI as iodine source and aerial O2 as oxidant
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The laccase-catalyzed iodination of p-hydroxyarylcarbonyl- and p-hydroxyarylcarboxylic acid derivatives using KI as iodine source and aerial oxygen as the oxidant delivers the corresponding iodophenols in a highly efficient and sustainable manner with yields up to 93% on a preparative scale under mild reaction conditions.
- Sdahl, Mark,Conrad, Jürgen,Braunberger, Christina,Beifuss, Uwe
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p. 19549 - 19559
(2019/07/05)
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- Process for preparing biphenyl compounds
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The present invention relates to a process for preparing a compound having the formula (I), said process comprising the following steps: a) the addition of an oxygen source into a solution of a compound of formula (II), in a water-miscible solvent, b) the addition of a laccase in the solution obtained after step a); and c) the possible recovering of the compound of formula (I) thus obtained.
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Page/Page column 18; 22-24
(2019/01/04)
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- A new highly selective chromogenic and fluorogenic chemosensor for copper (II)
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A new fluorogenic and chromogenic probe (L) for the selective, sensitive and naked-eye detection of Cu2+ is reported. Complexation constant, complex stoichiometry and quantum chemical (DFT) calculation for Cu2+ complex has been determined. Also, detection limits and the selectivity in front of other divalent and trivalent cations have been evaluated.
- Quindt, Matías I.,Gutierrez, Leandro G.,Kneeteman, María N.,Mancini, Pedro M. E.,Parra, Margarita,Gil, Salvador,Costero, Ana M.
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p. 659 - 664
(2018/07/14)
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- Facile synthesis of vanillin-based novel bischalcones identifies one that induces apoptosis and displays synergy with Artemisinin in killing chloroquine resistant Plasmodium falciparum
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The inherent affinity of natural compounds for biological receptors has been comprehensively exploited with great success for the development of many drugs, including antimalarials. Here the natural flavoring compound vanillin has been used as an economical precursor for the synthesis of a series of novel bischalcones whose in vitro antiplasmodial activities have been evaluated against erythrocytic stages of Plasmodium falciparum. Bischalcones 9, 11 and 13 showed promising antiplasmodial activity {Chloroquine (CQ) sensitive Pf3D7 IC50 (μM): 2.0, 1.5 and 2.5 respectively}but only 13 displayed potent activities also against CQ resistant PfDd2 and PfIndo strains exhibiting resistance indices of 1.4 and 1.5 respectively. IC90 (8 μM) of 13 showed killing activity against ring, trophozoite and schizont stages. Further, 13 initiated the cascade of reactions that culminates in programmed cell death of parasites including translocation of phosphatidylserine from inner to outer membrane leaflet, loss of mitochondrial membrane potential, activation of caspase like enzyme, DNA fragmentation and chromatin condensation. The combinations of 13 + Artemisinin (ART) exhibited strong synergy (ΣFIC50:0.46 to 0.58) while 13 + CQ exhibited mild synergy (ΣFIC50: 0.7 to 0.98) to mild antagonism (ΣFIC50: 1.08 to 1.23) against PfIndo. In contrast, both combinations showed marked antagonism against Pf3D7(ΣFIC50: 1.33 to 3.34). These features of apoptosis and strong synergy with Artemisinin suggest that bischalcones possess promising antimalarial drug-like properties and may also act as a good partner drugs for artemisinin based combination therapies (ACTs) against Chloroquine resistant P. falciparum.
- Sharma, Upendra K.,Mohanakrishnan, Dinesh,Sharma, Nandini,Equbal, Danish,Sahal, Dinkar,Sinha, Arun K.
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p. 623 - 638
(2018/06/26)
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- Synthesis of nitrogenated lignin-derived compounds and reactivity with laccases. Study of their application in mild chemoenzymatic oxidative processes
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The chemical synthesis of a series of lignin-derived nitrogenated compounds was performed in high yields (73-99%) through simple conventional chemical transformations starting from natural monomers such as vanillin, syringaldehyde or 3,4-dihydroxybenzaldehyde. The study of the vanillin-derived compounds as substrates for commercially available laccases from Trametes versicolor and Myceliophthora thermophila in oxidative transformations, generally led to the isolation of several dimeric species in high to excellent conversions (>70%), while for hydrazone derivatives a more rapidly oxidative coupling was evidenced by the formation of oligomers and/or polymers. Remarkably, vanillin was obtained due to the hydrolysis of some of the nitrogenated functional groups, such as the hydrazone or the hydrazono tetrazole. The three families of lignin-derived compounds can provide a great source of new laccase-mediator systems (LMS), the possibility of employing them for lignin modification being particularly attractive. Preliminary experiments showed promising levels of activity towards the oxidation of a monomer (veratryl alcohol, up to 70% conversion) and a dimer (adlerol, up to 22% conversion) lignin models, higher than those achieved with the natural vanillin and syringaldehyde (up to 7% conversion with veratryl alcohol and almost negligible conversion with adlerol), these processes being also highly influenced by the pH of the reaction medium.
- Albarrán-Velo, Jesús,López-Iglesias, María,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
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p. 50459 - 50471
(2017/11/10)
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- The test compound is evaluated [...] bond cleavage (by machine translation)
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[A] compounds of specific molecules in a reaction model for evaluating [...] bond cleavage to prevent inversion of the evaluation test for the new compound [...] bond cleavage, and its manufacturing method. The specific structure of the "1" [a] [...] bond cleavage evaluation test for the new compound, "2" for the evaluation test of the method of manufacturing compound [...] bond cleavage, "3" for a particular compound having a structure, "4" and the method of producing the compound. [Drawing] no (by machine translation)
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Paragraph 0051
(2017/04/25)
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- Synthesis of new ferrocenyl dehydrozingerone derivatives and their effects on viability of PC12 cells
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A series of novel compounds deriving from the conjugation of ferrocene with curcumin-related bioactive molecules as dehydrozingerone, zingerone and their biphenyl dimers was prepared by Claisen-Schmidt condensation of the suitable aromatic aldehydes and acetylferrocene in different conditions according to the starting material. The obtained compounds were fully characterized by NMR spectroscopy and cyclic voltammetry and reversible electrochemical behavior was recorded for monomer derivatives. The cell viability of PC12 cells after exposure to the organometallic compounds was also evaluated and a reduced toxicity with respect to the ferrocene was detected. In comparison with biphenyl 4, a compound that manifested antiproliferative and apoptotic activities and was quite toxic on PC12 cells, the exposure to the ferrocenyl analogue 14 resulted in roughly fourfold increase in the cell viability. Ferrocenyl chalcones 14 and 16-18 significantly increased the oxidative stress generated by hydrogen peroxide, a molecule generally accumulated in cancer cells and, recently, studied as prodrug.
- Pedotti, Sonia,Patti, Angela,Dedola, Sonia,Barberis, Antonio,Fabbri, Davide,Dettori, Maria Antonietta,Serra, Pier Andrea,Delogu, Giovanna
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- The synthesis and analysis of advanced lignin model polymers
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If the lignin-first biorefinery concept becomes a reality, high quality lignins close in structure to native lignins will become available in large quantities. One potential way to utilise this renewable material is through depolymerisation to aromatic chemicals. This will require the development of new chemical methods. Here, we report the synthesis and characterisation of advanced lignin model polymers to be used as tools to develop these methods. The controlled incorporation of the major linkages in lignin is demonstrated to give complex hardwood and softwood lignin model polymers. These polymers have been characterised by 2D HSQC NMR and GPC analysis and have been compared to isolated lignins.
- Lancefield,Westwood
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supporting information
p. 4980 - 4990
(2015/11/16)
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- Chemoenzymatic total synthesis of a naturally occurring (5-5′)/(8′-O-4-″) dehydrotrimer of ferulic acid
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The cross-linking of plant cell walls by ferulate dehydrodimerization reactions is well established. Recently, a (5-5′)/(8′-O-4-″) dehydrotrimer of ferulic acid (A) was isolated from alkali extracts of maize bran. Its structure was elucidated on the basis of an extensive structural analysis (UV, MS, 1D and 2D NMR). This first identified ferulic acid dehydrotrimer has revealed that parietal polysaccharide chains can be more extensively cross-linked than has been previously recognized. To produce the (5-5′)/(8′-O-4-″) dehydrotrimer (A) in sufficient high-purity quantities and allow the development of analytical methodologies (e.g., LC/GC, immunohistochemistry) to identify and quantify this peculiar trimer in plant extracts or samples, its first total convergent synthesis has been achieved in 10 steps and in 18 % yield starting from commercially available vanillin by horseradish peroxidase mediated enzymatic aryl-aryl coupling, aldolization/crotonization, and Wittig olefination reactions as the key steps. The first total convergent synthesis of the naturally occurring (5-5′)/(8′-O-4-″) dehydrotrimer of ferulic acid (A) has been achieved in 10 steps and in 18 % yield starting from commercially available vanillin using horseradish peroxidase mediated enzymatic aryl-aryl coupling, aldolization/crotonization, and Wittig olefination reactions as the key steps. Copyright
- Mouterde, Louis M. M.,Flourat, Amandine L.,Cannet, Molly M. M.,Ducrot, Paul-Henri,Allais, Florent
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p. 173 - 179
(2013/02/23)
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- Small molecules interacting with α-synuclein: Antiaggregating and cytoprotective properties
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Curcumin, a dietary polyphenol, has shown a potential to act on the symptoms of neurodegenerative disorders, including Alzheimer's and Parkinson's diseases, as a consequence of its antioxidant, anti-inflammatory and anti-protein aggregation properties. Unfortunately, curcumin undergoes rapid degradation at physiological pH into ferulic acid, vanillin and dehydrozingerone, making it an unlikely drug candidate. Here, we evaluated the ability of some curcumin by-products: dehydrozingerone (1), its O-methyl derivative (2), zingerone (3), and their biphenyl analogues (4-6) to interact with α-synuclein (AS), using CD and fluorescence spectroscopy. In addition, the antioxidant properties and the cytoprotective effects in rat pheochromocytoma (PC12) cells prior to intoxication with H2O 2, MPP+ and MnCl2 were examined while the Congo red assay was used to evaluate the ability of these compounds to prevent aggregation of AS. We found that the biphenyl zingerone analogue (6) interacts with high affinity with AS and also displays the best antioxidant properties while the biphenyl analogues of dehydrozingerone (4) and of O-methyl-dehydrozingerone (5) are able to partially inhibit the aggregation process of AS, suggesting the potential role of a hydroxylated biphenyl scaffold in the design of AS aggregation inhibitors.
- Marchiani, Anna,Mammi, Stefano,Siligardi, Giuliano,Hussain, Rohanah,Tessari, Isabella,Bubacco, Luigi,Delogu, Giovanna,Fabbri, Davide,Dettori, Maria A.,Sanna, Daniele,Dedola, Sonia,Serra, Pier A.,Ruzza, Paolo
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p. 327 - 338
(2013/08/23)
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- Vanillin based polymers: I. An electrochemical route to polyvanillin
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Electrochemical reductive polymerization of divanillin in aqueous sodium hydroxide using a lead cathode gives polyvanillin in 91% yield. The product was characterized by elemental analysis, UV-Vis, FT-IR, 1H, 13C NMR, TGA-DTGA, and GPC.
- Amarasekara, Ananda S.,Wiredu, Bernard,Razzaq, Ashfaqur
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supporting information
p. 2395 - 2397
(2013/02/22)
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- On the reactions of two fungal laceases differing in their redox potential with lignin model compounds: products and their rate of formation
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Laceases (EC 1.10.3.2) are multicopper oxidases able to oxidize phenolic compounds such as lignin-related polyphenols. Since the discovery that so-called mediators effectively extend the family of lacease substrates, direct interactions between lignin-like materials and lacease have gained much less attention. In this work, the aim was to characterize oxidation products formed in direct laccase-catalyzed oxidation of different guaiacylic and syringylic lignin model compounds with two different laceases: a low redox potential Melanocarpus alborneces lacease and a high redox potential Trametes hirsuta lacease. By following the formation of different, mainly biphenylic (5-5) and benzylic oxidation products, it was found that although both of these enzymes generated practically the same pattern of products with particular types of syringyl and guaiacyl compounds, in some cases a clear difference in the rates of their formation was observed. The results also confirm further to the suggestions that syringylic compounds are able to act as mediators in their own oxidation reactions and also that in some instances acetylation of phenolic material may produce altered, unexpected structures.
- Maarit, Lahtinen,Kristiina, Kruus,Petri, Heinonen,Jussi, Sipilae
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experimental part
p. 8357 - 8365
(2010/08/19)
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- Development of novel antiatherogenic biaryls: Design, synthesis, and reactivity
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On the basis of the 5,5′-bisvanillin scaffold, a series of compounds has been synthesized presenting symmetric or dissymmetric frames on each phenolic moiety. These frames are α,β-unsaturated (fluoro)phosphonate and/or α,β-unsaturated hydrazone(s) formed by coupling aldehydic with isoniazid or hydralazine. All compounds were tested for their ability to inhibit cell-mediated low-density lipoprotein oxidation. Oxidized low-density lipoprotein induced cytotoxicity was also evaluated along with the carbonyl scavenger properties of selected compounds. The most efficient agents were found to be those possessing at least one hydralazinone frame, with the most potent being the symmetrical compound: 4,4′-dihydroxy-3,3′-dimethoxy-5, 5′-biphenyl-1,1′-(diphthalazin-1-yl)methylhydrazone hydrochloride.
- Delomenède, Mélanie,Bedos-Belval, Florence,Duran, Hubert,Vindis, Cécile,Baltas, Michel,Nègre-Salvayre, Anne
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experimental part
p. 3171 - 3181
(2009/04/11)
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- Studies of nitrile oxide cycloadditions, and the phenolic oxidative coupling of vanillin aldoxime by Geobacillus sp. DDS012 from Italian rye grass silage
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During studies directed towards the discovery of nitrile hydrolysing enzymes from thermophiles, vanillin aldoxime was incubated with the thermophilic organism, Geobacillus sp. DDS012 isolated from Italian rye grass (Lolium multiflorum) silage. The predominant product was a dihydro-dimer, which could only be characterised by LC-MS. This was initially imagined to be the product of cycloaddition of vanillin aldoxime with the corresponding nitrile oxide, but preparation of the supposed adduct and model studies excluded this possibility. The rate constant for the second order dimerisation of 4-O-acetyl vanillin nitrile oxide was measured (1.21 × 10-4 M-1 s -1, 0.413 M, 25 °C) and the 13C-NMR signal for the nitrile oxide carbon was observed (δC 34.4, br. t 1J13C,14N circa 50 Hz). Treatment of vanillin aldoxime with potassium persulfate and iron sulfate gave material with the same LC-MS properties as the natural product, which is therefore identified as 5,5′-dehydro-di-(vanillin aldoxime) 1d formed by phenolic oxidative coupling. This journal is The Royal Society of Chemistry.
- Kelly, David R.,Baker, Simon C.,King, David S.,De Silva, Deepa S.,Lord, Gwyn,Taylor, Jason P.
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p. XX787-796
(2008/09/17)
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- Structural modification of phenylpropanoid-derived compounds and the effects on their participation in redox processes
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Oxidation and reduction processes are fundamental to many of the proposed mechanisms by which dietary phytochemicals are thought to exert protective effects against cardiovascular disease and some cancers. An understanding of the redox chemistry of these compounds is essential in assessing their potential to participate in these processes. Phenylpropanoid-derived compounds were selected and synthesised where required to represent many of the structural features found in this important group of compounds. Using electron paramagnetic resonance spectroscopy and computational chemistry a structure-redox activity relationship was obtained. Good correlation of computational and experimental results was observed for the mono-hydroxylated compounds. This demonstrated the value of computational chemistry in obtaining information about compounds, not readily available and the effect of electron delocalisation on parent radical stability. For compounds containing more than one hydroxyl, the relationship was found to be more complex. The importance of quinone formation in compounds containing more than one hydroxyl substituent was highlighted, as this was found to have a significant effect on stabilisation and therefore, their participation in redox processes.
- Russell, Wendy R.,Scobbie, Lorraine,Chesson, Andrew
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p. 2537 - 2546
(2007/10/03)
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- Structural diversity of peroxidase-catalyzed oxidation products of o-methoxyphenols
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Equation presented. The biocatalytjc oxidation of o-methoxyphenolic compounds led to a variety of oligophenols (dimers to pentamers) and some of their oxidation products. The reaction was carried out in an aqueous medium at room temperature with hydrogen peroxide as the terminal oxidant in a facile and green route to potentially bioactive compounds. Detailed structural information on the products of peroxidase-catalyzed oxidation of o-methoxyphenols is presented for the first time.
- Antoniotti, Sylvain,Santhanam, Lakshmi,Ahuja, Disha,Hogg, Michael G.,Dordick, Jonathan S.
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p. 1975 - 1978
(2007/10/03)
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- Chemopreventive potential of cyclic diarylheptanoids.
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Eleven cyclic diarylheptanoids and seven related compounds were screened as potential antitumor promoters by using the in vitro short-term 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus early antigen (EBV-EA) activation assay. In addition, the cyclic diarylheptanoid myricanone (2) was examined for antitumor initiating activity in a two-stage carcinogenesis assay of mouse skin tumors induced by peroxynitrite as an initiator and TPA as a promoter. Myricanone (2) exhibited significant antitumor-initiating effect on mouse skin. These data suggest that cyclic, as well as linear, diarylheptanoids might be valuable chemopreventors.
- Ishida, Junko,Kozuka, Mutsuo,Tokuda, Harukuni,Nishino, Hoyoku,Nagumo, Seiji,Lee, Kuo Hsiung,Nagai, Masahiro
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p. 3361 - 3365
(2007/10/03)
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- Attempt to approach the role of phenolic phenylpropenol structures in the photoyellowing of softwood mechanical pulps
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Three biphenyl (I, II, III) compounds and a benzylarylether (IV) compound were synthesized to detect and quantify the presence of phenolic phenylpropenols in unbleached, peroxide-bleached, or sodium borohydride-reduced mechanical softwood pulps. The methodology used is based on a gas chromatography - mass spectrometry search of the prepared compounds in the residue obtained after ethylation, thioacidolysis, and desulfurization of the pulps. Detection of biphenyl I (≈4 × 10-6 mol g-1) in unbleached and NaBH4-reduced pulps is indicative of the presence of phenolic coniferaldehyde units in these pulps. Traces of biphenyl II, found in the peroxide-bleached pulp, probably came from ferulic acid units formed by oxidation of coniferaldehyde by H2O2. No biphenyl ether III or benzylaryl ether IV were detected in the three pulps. This result indicates that phenolic phenylpropenol units are not present in softwood mechanical pulps and do not contribute to the fast part of their photoyellowing.
- Ruffin, Brigitte,Grelier, Stephane,Nourmamode, Aziz,Castellan, Alain
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p. 1223 - 1231
(2007/10/03)
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- Structural studies on bioactive compounds. 32. Oxidation of tyrphostin protein tyrosine kinase inhibitors with hypervalent iodine reagents
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Hydroxylated styrenes (tyrphostins) undergo oxidation by hypervalent iodine oxidants such as [(diacetoxy)iodo]benzene (DAIB) to give a range of products depending on the structure of the phenolic substrate, the solvent, the oxidant stoichiometry, and the purification strategy. Conditions have been developed to modify the phenolic component of the tyrphostin without affecting the appended substituted-vinyl moiety. Novel products include: unstable 2-acyloxy-2-methoxy-4-(substituted-vinyl)cyclohexadienones and their rearrangement products 2-acyloxy-4-hydroxy-3-methoxy-1-(substituted- vinyl)benzenes; phenyliodoniophenolates and their rearrangement products iodophenoxytyrphostins; and 3,3'-dialkoxy-2,2'-dihydroxy-5,5'-di(substituted- vinyl)biphenyls. None of these oxidation products displayed enhanced activity in vitro in the NCI 60-cell line panel or in a panel of human breast cancer cell lines, compared to their tyrphostin precursors. The inhibitory activity of three representative tyrphostins (3e,n, 28) was not modulated by aerobic/anaerobic conditions in MCF-7 and MDA 468 cells and was independent of EGFR status in clones of ZR75B cells transfected with this receptor. Basal growth of MCF-7 cells was unaffected by co-administration of the growth factors EGF, TGF-α, IGF-I, and IGF-II, and the new agents did not inhibit EGFR and c-erbB2 autophosphorylation in cell lysates from MDA 468 or SkBr3 cells, respectively, suggesting that receptor tyrosine kinases are not targets for these compounds. Growth stimulation by the tyrphostin 3n in the ER+ breast cell lines MCF-7, T47D, and ZR75-1 was abolished by 1 μM tamoxifen, suggesting that this compound has estrogen agonist activity.
- Wells, Geoffrey,Seaton, Angela,Steven, Malcolm F. G.
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p. 1550 - 1562
(2007/10/03)
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- Characterization of high molecular mass fractions of receiving waters and sediments of a pulp mill by CuO-oxidation and HPLC
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High molecular mass fractions were separated by ultrafiltration from water samples collected at four sampling stations downstream and one upstream of a kraft pulp mill. These fractions and three sediment samples containing high molecular mass organic compound were degraded by alkaline cupric oxide oxidation. Lignin and humic compounds in fractions were characterized analyzing their oxidation products by reversed phase HPLC and photodiode array detection. -from Authors
- Hyotylainen,Knuutinen,Vilen
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p. 891 - 906
(2007/10/03)
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- OXOAMMONIUM SALTS. 4. A NEW REAGENT FOR PHENOL COUPLING
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Oxoammonium salts, such as 2,2,6,6-tetramethylpiperidine-1-oxonium tetrafluoroborate, oxidatively couple phenols to dihydroxybiphenyls in good yield.Furthermore, these compounds can be used to dehydrogenate tertiary amines to iminium salts and to oxidize certain phenols to quinones.
- Bobbitt, James M.,Ma, Zhenkun
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p. 641 - 648
(2007/10/02)
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