- Continuous flow study of isoeugenol to vanillin: A bio-based iron oxide catalyst
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The use of a biorefinery co-product, such as humins, in combination with an iron precursor in a solvent-free method yields a catalytic material with potential use in selective oxidative cleavage reactions. In particular, this catalyst was found active in the hydrogen-peroxide assisted oxidation of a naturally extracted molecule, isoeugenol, to high added-value flavouring agent, vanillin. By carrying out the reaction in continuous flow, not only a better understanding of the reaction mechanism and of the catalyst deactivation can be achieved, but also important insights for optimised conditions can be developed. The findings of this paper could pave the way to a more sustainable process for the production of a valuable food and perfume additive, vanillin.
- Filiciotto, Layla,Márquez-Medina, María Dolores,Pineda, Antonio,Balu, Alina M.,Romero, Antonio A.,Angelici, Carlo,de Jong, Ed,van der Waal, Jan C.,Luque, Rafael
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p. 281 - 290
(2019/12/25)
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- (±)-trans-2-phenyl-2,3-dihydrobenzofurans as leishmanicidal agents: Synthesis, in vitro evaluation and SAR analysis
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Leishmaniasis, a neglected tropical disease caused by parasites of the genus Leishmania, causes a serious burden of disease around the world, represents a threat to the life of millions of people, and therefore is a major public health problem. More effective and non-toxic new treatments are required, especially for visceral leishmaniasis, the most severe form of the disease. On the backdrop that dihydrobenzofurans have previously shown antileishmanial activity, we present here the synthesis of a set of seventy trans-2-phenyl-2,3-dihydrobenzofurans and evaluation of their in vitro activity against Leishmania donovani as well as a discussion of structure-activity relationships. Compounds 8m-o and 8r displayed the highest potency (IC50 4.6). Nonetheless, structural optimization as further requirement was inferred from the high clearance of the most potent compound (8m) observed during determination in vitro of its metabolic stability. On the other hand, chiral separation of 8m and subsequent biological evaluation of its enantiomers demonstrated no effect of chirality on activity and cytotoxicity. Holistic analysis of in silico ADME-like properties and ligand efficiency metrics by a simple scoring function estimating druglikeness highlighted compounds 16c, 18 and 23 as promising candidates for further development. Overall, the potential of trans-2-phenyl-2,3-dihydrobenzofurans as leishmanicidal agents was confirmed.
- Bernal, Freddy A.,Gerhards, Marcel,Kaiser, Marcel,Wünsch, Bernhard,Schmidt, Thomas J.
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- Task-Specific Catalyst Development for Lignin-First Biorefinery toward Hemicellulose Retention or Feedstock Extension
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A catalytic reductive fractionation method for lignocellulosic biomass, termed lignin-first biorefinery, has emerged, which emphasises preferential depolymerization of the protolignin. However, in most studies, the lignin-first biorefinery is only effective for hardwood that has a high syringyl/guaiacol (S/G) ratio of lignin building blocks, and the degradation of hemicellulose also takes place simultaneously to a certain degree. In this study, two task-specific catalysts were developed to realize hemicellulose retention and feedstock extension through the development of an objective performance–structure relationship. It is found that MoxC/carbon nanotube (CNT) is highly selective in the cleavage of bonds between carbohydrates and lignin and ether bonds in lignin during the catalytic reductive fractionation of hardwood, leading to a carbohydrate (both cellulose and hemicellulose) retention degree in the solid product close to the theoretical maximum and a delignification degree as high as 98.1 %. Ru/CMK-3 is demonstrated to be effective in the catalytic reductive fractionation of softwood and grass, resulting from its weak acidity and high mesoporosity.
- Qiu, Shi,Guo, Xuan,Huang, Yong,Fang, Yunming,Tan, Tianwei
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p. 944 - 954
(2019/01/08)
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- Synthesis and characterization of di-μ-oxidovanadium(V), oxidoperoxido-vanadium(V) and polymer supported dioxidovanadium(V) complexes and catalytic oxidation of isoeugenol
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The tridentate ONN donor ligand, Hbzpy-fah (I) (Hbzpy-fah = Schiff base derived from 2-benzoylpyridine and 2-furoylhydrazide) upon reaction with [VIVO(acac)2] in methanol followed by aerial oxidation give a dinuclear complex, [{VVO(bzpy-fah)}2(μ-O)2] (1) having [{VVO}2(μ-O)2]2+ core. Treatment of 1 with H2O2 in methanol results in the formation of dinuclear peroxido complex, [{VVO(bzpy-fah)}2(μ-O2)2] (2). The molecular structure of 2 was determined by single-crystal X-ray diffraction, confirming the ONN binding mode of I and μ-bis(peroxido) with side-on coordination. Reaction of 1 with imidazolomethylpolystyrene cross-linked with 5% divinylbenzene (PS-im) in DMF gives the polymer-supported complex 3 (abbreviated as PS-im[VVO2(bzpy-fah)]) which was characterized by field-emission scanning electron micrographs (FE-SEM) as well as energy dispersive X-ray (EDAX), atomic force microscopy (AFM) and thermal analysis along with usual spectroscopic techniques. Complexes 1 and 3 have been used as catalyst precursors for the oxidation of isoeugenol in the presence of aqueous H2O2 as oxidant and gave vanillin, vanillic acid and dehydrodiisoeugenol. The polymer-supported complex showed higher conversion than its neat counterpart. This has also allowed for recyclable catalytic system with increased catalyst lifetime and thus proved to be better over the homogeneous counterpart.
- Maurya, Mannar R.,Uprety, Bhawna,Chaudhary, Nikita,Avecilla, Fernando
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p. 230 - 238
(2015/06/30)
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- Selective Activation of C=C Bond in Sustainable Phenolic Compounds from Lignin via Photooxidation: Experiment and Density Functional Theory Calculations
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Lignocellulosic biomass can be converted to high-value phenolic compounds, such as food additives, antioxidants, fragrances and fine chemicals. We investigated photochemical and heterogeneous photocatalytic oxidation of two isomeric phenolic compounds from lignin, isoeugenol and eugenol, in several nonprotic solvents, for the first time by experiment and the density functional theory (DFT) calculations. Photooxidation was conducted under ambient conditions using air, near-UV light and commercial P25 TiO2 photocatalyst, and the products were determined by TLC, UV-Vis absorption spectroscopy, HPLC-UV and HPLC-MS. Photochemical and photocatalytic oxidation of isoeugenol proceeds via the mild oxidative "dimerization" to produce the lignan dehydrodiisoeugenol (DHDIE), while photooxidation of eugenol does not proceed. The DFT calculations suggest a radical stepwise mechanism for the oxidative "dimerization" of isoeugenol to DHDIE as was calculated for the first time.
- Zielinski, Morgan,Burke, Luke A.,Samokhvalov, Alexander
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p. 1332 - 1339
(2015/11/10)
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- Oxidovanadium(iv) and dioxidovanadium(v) complexes of hydrazones of 2-benzoylpyridine and their catalytic applications
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Reactions between the tridentate ONN donor ligands, Hbzpy-tch (I) and Hbzpy-inh (II), with [VIVO(acac)2] in dry methanol give two different types of complexes, [VIVO(acac)(bzpy-tch)] (1) and [VIVO(OMe)(bzpy-inh)] (2), respectively. Irrespective of their nature in methanol upon aerial oxidation and precipitation both yield dinuclear [{VVO(bzpy-tch)}2(μ-O)2] (3) and [{VVO(bzpy-inh)}2(μ-O)2] (4). Treatment of 1 or 2 in methanol with H2O2 yields the oxidomonoperoxidovanadium(v) complexes [{VVO(bzpy-tch)}2(μ-O2)2] (5) and [VVO(O2)(bzpy-inh)] (6). Reactions of 3 and 4 with imidazolomethylpolystyrene cross-linked with 5% divinylbenzene (PS-im) in DMF give the polymer-supported PS-im[VVO2(bzpy-inh)] (7) and PS-im[VVO2(bzpy-tch)] (8). The compounds are characterized by various spectroscopic techniques and compounds 7 and 8 were also analyzed by thermal, atomic force microscopy (AFM), field-emission scanning electron micrographs (FE-SEM) as well as energy dispersive X-ray (EDAX) studies. The molecular structures of 3-5 and of [VVO(O2)(bzpy-inh)(H2O)]·0.5MeOH (6a) were determined by single-crystal X-ray diffraction, confirming the μ-bis(O) and ONN binding mode in the dinuclear complexes 3 and 4, as well as the side-on coordination of the peroxido ligand in 5 and 6a. The polymer-grafted compounds 7 and 8 were used for the catalytic oxidation of isoeugenol using aqueous H2O2 as an oxidant. The intermediate peroxido species, expected to be involved during catalytic action, were also generated from solutions of 1-4 and studied by UV-Vis and 51V NMR. The catalytic activity of the several systems was tested and the polymer-supported versions showed higher conversions than their neat counterparts. The polymer-supported complexes allow for recyclable catalytic systems, thus providing additional advantages over their homogeneous counterparts in terms of increased catalyst lifetime and easier separation from the reaction mixture. This journal is
- Maurya, Mannar R.,Chaudhary, Nikita,Avecilla, Fernando,Ad?o, Pedro,Costa Pessoa, Jo?o
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p. 1211 - 1232
(2015/02/02)
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- Radical synthesis of tetrameric lignin model compound
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Abstract The lack of suitable lignin model compound limits the understanding of the characteristics of lignin, and hence hinders the efficient utilization of this kind of bioresource. A tetramer phenolic lignin model compound composed of 5-5, α-O-4 and β-
- Ouyang, Xin-Ping,Yang, Yun,Zhu, Guo-Dian,Qiu, Xue-Qing
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p. 980 - 982
(2015/08/18)
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- USE OF DIHYDRODEHYDRODIISOEUGENOL AND PREPARATIONS COMPRISING DIHYDRODEHYDRODIISOEUGENOL
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This invention relates to cosmetic and pharmaceutical preparations comprising (i) a diastereomer or a mixture of two or more diastereomers of the compound of formula (I) or (ii) a salt of a diastereomer or of a mixture of two or more diastereomers of the compound of formula (I) or (iii) a mixture of two or more salts of a diastereomer or of a mixture of two or more diastereomers of the compound of formula (I), a diastereomer, salt or a mixture as defined above as a drug for topical application and/or for the treatment of lipoatrophy; the non-therapeutic use of a diastereomer, salt or a mixture as defined above for the prevention, treatment or reduction of skin aging, especially skin wrinkles; the use of a diastereomer, salt or a mixture as defined above for the production of an orally administered non-pharmaceutical preparation.
- -
-
Paragraph 0192; 0193
(2013/05/08)
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- Cerium ammonium nitrate-mediated the oxidative dimerization of p-alkenylphenols: A new synthesis of substituted (±)-trans- dihydrobenzofurans
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A new method for the preparation of substituted dihydrobenzofurans is described. The p-alkenylphenols, mediated by cerium ammonium nitrate (CAN), undergo the oxidative dimerization to generate substituted dihydrobenzofurans including (±)-conocarpan, (±)-licarin A, (±)-acuminatin, as well as their related substituted dihydrobenzofurans.
- Chen, Po-Yuan,Wu, Yi-Hua,Hsu, Mon-Huei,Wang, Tzu-Pin,Wang, Eng-Chi
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p. 653 - 657
(2013/07/27)
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- Anodic oxidation on a boron-doped diamond electrode mediated by methoxy radicals
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Direct evidence: The existence of methoxy radical species formed during an anodic oxidation in MeOH on a boron-doped diamond (BDD) electrode was confirmed by ESR spectroscopy. Effective production of a neolignan, licarinA, was accomplished by the BDD-medi
- Sumi, Takenori,Saitoh, Tsuyoshi,Natsui, Keisuke,Yamamoto, Takashi,Atobe, Mahito,Einaga, Yasuaki,Nishiyama, Shigeru
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supporting information; experimental part
p. 5443 - 5446
(2012/07/14)
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- Oxidative cleavage of isoeugenol to vanillin under molecular oxygen catalysed by cobalt porphyrin intercalated into lithium taeniolite clay
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Three types of Co-porphyrin complexes differing in their porphyrin-ring substituents and nonionic or cationic structure were intercalated into lithium taeniolite (LiTN) using a simple cation exchange method. All the intercalated catalysts displayed expanded clearance spaces (in the range of 0.30-0.51 nm) compared with that of the parent LiTN (0.24 nm). The catalysts were applied for the oxidative cleavage of isoeugenol to vanillin with molecular oxygen as the sole oxidant, and the reaction proceeded effectively under mild reaction conditions. The highest vanillin selectivity of 72% was obtained with CoTPyP/TN, which had the widest clearance space among the three Co-porphyrin catalysts. These intercalated catalysts showed high stability during oxidation, enabling their recycling for at least three runs.
- Adilina, Indri Badria,Hara, Takayoshi,Ichikuni, Nobuyuki,Shimazu, Shogo
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experimental part
p. 72 - 79
(2012/08/08)
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- Screening of plant cell cultures for their capacity to dimerize eugenol and isoeugenol: Preparation of dehydrodieugenol
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Nine plant cell cultures were used to catalyze the oxidative coupling reaction of eugenol and isoeugenol. All the evaluated plant cell cultures carried out the oxidative reaction. The calli of Medicago sativa and the cell suspension of Coriandrum sativum
- Hernandez-Vazquez, Liliana,Olivera-Flores, Ma. Teresa De Jesus,Ruiz-Teran, Francisco,Ayala, Ivon,Navarro-Ocana, Arturo
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experimental part
p. 102 - 106
(2012/07/01)
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- Metabolic characterization of newly isolated Pseudomonas nitroreducens Jin1 growing on eugenol and isoeugenol
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Newly isolated soil bacterium strain Jin1 was able to grow on both eugenol and isoeugenol each as sole source of carbon and energy. Based on bacterial 16S rDNA analysis, Jin1 belongs to Pseudomonas nitroreducens with a similarity of 98.92% (14/1297). P. nitroreducens Jin1 was found to biotransform eugenol and isoeugenol to vanillin by different pathways. Eugenol was biotransformed to vanillin through coniferyl alcohol and ferulic acid similarly to the pathway shown previously by Pseudomonassp. HR199 and vanillin produced from eugenol was rapidly metabolized to vanillic acid. Contrastively, Pseudomonas nitroreducens Jin1 did not appear to produce metabolic intermediates during the biotransformation of isoeugenol to vanillin which was finally biotransformed to vanillic acid with much slower rate. These results indicate that there seems to be different metabolic regulation systems for the biotransformation of eugenol and isoeugenol by this bacterium. Herein, we report on Pseudomonas nitroreducens Jin1, a novel bacterium that produces vanillin from eugenol and isoeugenol by two different metabolic pathways.
- Unno, Tatsuya,Kim, Soo-Jin,Kanaly, Robert A.,Ahn, Joong-Hoon,Kang, Su-Il,Hur, Hor-Gil
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experimental part
p. 8556 - 8561
(2009/09/29)
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- Simple synthesis of benzofuranoid neolignans from Myristica fragrans
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The total synthesis of four neolignans - fragnasols A (1), B (2), and C (3) and dehydrodiisoeugenol (4) - starting from the readily available phenol derivative isoeugenol (5) was accomplished. The key step of the synthesis of these natural products is a n
- Juhasz, Laszlo,Kuerti, Laszlo,Antus, Sandor
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p. 866 - 870
(2007/10/03)
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- Oxidative Studies on trans-(3-Phenyl-2-propenyl)phenols and 2-Methoxy-4-(2-propenyl)phenol and 2-Methoxy-4-(1-propenyl)phenol
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Oxidative reaction on trans-2-(3-phenyl-2-propenyl)phenols (1-4) and para-alkenylphenols have been studied.The products formed include benzofurane (5-8) and neolignane (16-18).
- Iyer, Meera R.,Baskaran, S.,Trivedi, Girish K.
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p. 341 - 344
(2007/10/02)
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- Regio- and Diastereo-selective Synthesis of Dimeric Lignans Using Oxidative Coupling
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The oxidative dimerization of monolignols such as (E)-isoeugenol (1), (E)-methyl ferulate (2) and (E)-coniferyl alcohol (3) has been performed using two catalytic systems: horseradish peroxidase (HRP)-H2O2 and tetraphenylporphyrinatomanganese(III) acetate
- Chioccara, Francesco,Poli, Sonia,Rindone, Bruno,Pilati, Tullio,Brunow, Goesta,et al.
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p. 610 - 616
(2007/10/02)
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- Photosensitized oxidation of isoeugenol in protic and aprotic solvents
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Sensitized photooxygenation of isoeugenol gave seven products in methanol, seven products in ethanol, six products in acetone, and five products in acetonitrile. One of the products is a 7,7'-linked lignan of a type which has not yet been observed in nature. The structures of these products were elucidated and the mechanisms of their formation are discussed.
- Kuo,Chen,Wang
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p. 2196 - 2200
(2007/10/02)
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- HORSERADISH PEROXIDASE-MEDIATED PREPARATION OF DIMERS FROM EUGENOL AND ISOEUGENOL
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Coupling of eugenol (I) and isoeugenol (II) by means of horseradish peroxidase and hydrogen peroxide resulted in ca. 20percent yield of dimeric compounds: 5,5'-diallyl-2,2'-dihydroxy-3,3'-dimethoxy-biphenyl (III) and 2-(4'-hydroxy-3'-methoxy)phenyl-7-meth
- Krawczyk, Andrzej R.,Lipkowska, Ewa,Wrobel, Jerzy T.
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p. 1147 - 1150
(2007/10/02)
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