- Microbial production of 4-vinylguaiacol from ferulic acid by Bacillus cereus SAS-3006
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Ferulic acid is an abundant cinnamic acid derivative found in the plant kingdom. It is a commercially available substrate utilized to produce flavor compounds such as 4-vinylguaiacol (4-VG), vanillin, and vanillic acid. The isolate Bacillus cereus SAS-3006 was screened and selected based on its ability to produce 4-VG upon ferulic acid biotransformation. It was identified based on morphological and physiochemical characteristics and its 16S ribosomal DNA sequence (GenBank accession number: KF699134). A maximum amount (79.4 mg/L) of 4-VG accumulation was observed on the 5th day of incubation when the culture was grown on 2.5 mM ferulic acid as sole carbon source. Further conversion of 4-VG to other intermediates such as vanillin, vanillic acid, protocatechuic acid, acetovanillone, and vanillyl alcohol was not observed. In-vitro conversion of ferulic acid to 4-VG was also studied with cell extracts of B. cereus SAS-3006. The present study provides the first evidence for production of 4-VG as the sole product using B. cereus SAS-3006.
- Mishra, Shashank,Sachan, Ashish,Vidyarthi, Ambarish Sharan,Sachan, Shashwati Ghosh
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- Synthesis of styrenes through the biocatalytic decarboxylation of trans-cinnamic acids by plant cell cultures
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A novel method for producing styrenes from trans-cinnamic acids was developed. When trans-cinnamic acid was incubated with plant cell cultures at room temperature, styrene was obtained. 4-Hydroxy-3-methoxystyrene (2a), 3-nitrostyrene (2f) and furan (2g) were synthesized quantitatively.
- Takemoto,Achiwa
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- Bioinspired Selective Synthesis of Heterodimer 8-5′ or 8- O-4′ Neolignan Analogs
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The bioinspired synthesis of heterodimer neolignan analogs is reported by single-electron oxidation of both alkenyl phenols and phenols individually, followed by a combination of the resultant radicals. This oxidative radical cross-coupling strategy can afford heterodimer 8-5′ or 8-O-4′ neolignan analogs selectively with the use of air as the terminal oxidant and copper acetate as the catalyst at room temperature.
- Dong, Kui,Zhao, Chuang-Yuan,Wang, Xiao-Ju,Wu, Li-Zhu,Liu, Qiang
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- The bio-based phthalocyanine resins with high Tg and high char yield derived from vanillin
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The conversion of bio-based vanillin into the heat-resistant polymers is investigated. Firstly, converting the aldehyde group of vanillin into a vinyl group obtained 2-methoxy-4-vinylphenol (S1), which was then treated with nitro-phthalonitrile to give 4-(2-methoxy-4-vinylphenoxy)phthalonitrile (S2). Secondly, thermal polymerization between S1 and S2 in a different molar ratio gave a series of vanillin–based phthalocyanine (V-PN) resins that display high char yield and high Tg. The best result was obtained when the molar ratio between S1 and S2 was 1–50 and the obtained V-PN resin displayed a char yield of up to 76%, a Tg over 400 °C. These data are much better than those of the widely used petroleum-based phthalocyanine resins, suggesting that these bio-based functional monomers derived from vanillin are suitable as the precursors for the fabrication of the ablation-resistant materials in the application of the aerospace industry.
- Wang, Caiyun,Shi, Manling,Fang, Linxuan,Dai, Menglu,Huang, Gang,Sun, Jing,Fang, Qiang
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- Rapid transformation of ferulic acid to 4-vinyl guaiacol by Bacillus pumilus S-1
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A Bacillus pumilus strain S-1, earlier reported to efficient in converting of isoeugenol to vanillin, was found to have the biotransformation ability of ferulic acid. This strain rapidly dissimilated 1 g L-1 ferulic acid within 3 h and 4-vinyl guaiacol was identified as the main product. The highest concentration of 4-vinyl guaiacol, 0.72 g L-1, was obtained with a molar yield of 93.1 %. Different from former reports, 4-vinyl guaiacol was not further metabolized and no other vanilla flavour compounds were found.
- Hua, Dong-Liang,Liang, Xiao-Hui,Zhang, Xiao-Dong,Zhang, Jie,Xu, Hai-Peng,Li, Yan,Xu, Ping
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- Host attractants for red weevil, Rhynchophorus ferrugineus: Identification, electrophysiological activity, and laboratory bioassay
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A steam distillate from the freshly cut young bark of coconut palm Cocos nucifera was analyzed by gas chromatography, combined gas chromatography-electroantennographic detection (GC-EAD) and GC-MS to detect host attractants for the curculionid weevil Rhynchophorus ferrugineus, one of the major coconut pests in Sri Lanka. A twin FID peak consisting of a minor and a major component was shown to possess electrophysiological (EAG) activity. The minor peak was identified as γ-nonanoic lactone 2, while the major peak was identified as 4-hydroxy-3-methoxystyrene 2. In an EAG assay the synthetic racemic nonanoic lactone 1 did not elicit a considerable response in the antenna of R. ferrugineus, whereas the laboratory synthesized 2 showed activity. In a laboratory bioassay using a Y-type olfactometer, synthetic 1 and 2 elicited moderate attractant properties to R. ferrugineus, whereas a 1:1 mixture of the compounds showed increased attraction over that of the individual compounds.
- Gunawardena, Neelakanthi E.,Kern, Friedrich,Janssen, Edelgard,Meegoda, Chandana,Schaefer, Doris,Vostrowsky, Otto,Bestmann, Hans Juergen
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- Synthesis, Surface Properties and Effect of an Amino Acid Head Group of 11-(2-Methoxy-4-vinylphenoxy)undecanoicacid-Based Anionic Surfactants
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Our present research describes the surface properties of three biobased anionic surfactant synthesized from vinylguaiacol and 11-bromo undecanoic acid. To further improve its hydrophobicity and bioavailability, amino acid head group incorporation was carried out. All these synthesized compounds were thoroughly characterized using NMR and mass spectroscopy. The performance properties such as foaming, wetting, emulsification value and calcium tolerance were evaluated. The studied surfactants possess excellent emulsion stability and moderate calcium tolerance as compared to commercially available surfactant sodium lauryl sulfate (SLS). The micelle formation and the thermodynamics involved at the air–water interface were estimated from surface tension measurements. These surfactants showed a higher tendency towards adsorption at the air–water interface than micellization. Dynamic light scattering and steady state fluorescence anisotropy study were carried out to shed light on the bulk micellization properties of the synthesized surfactant. Along with spherical micelles of?5?nm size, larger aggregates (35–84?nm) were observed with higher anisotropy values. FESEM images further confirmed the larger spherical micelles formed by these surfactants. The surfactants formed chiral aggregates above the critical micelle concentration as indicated by circular dichroism spectra. These surfactants may be suitable candidates for additives to detergents to improve their calcium tolerance especially in the case of hard water. Furthermore, a low foaming ability along with high emulsion stability may find these surfactants to be better replacement of the conventional surfactant used as emulsifiers in many industrial applications.
- Darapureddi, Prabhakara Rao,Nayak, Rati Ranjan
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- Synthesis of Lipophilic Antioxidants by a Lipase-B-Catalyzed Addition of Peracids to the Double Bond of 4-Vinyl-2-methoxyphenol
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4-Vinyl guaiacol (2) was lipophilized through the electrophilic addition of peracids to its vinylic double bond. Those peracids were formed in situ, by the Candida antarctica lipase-B-assisted perhydrolysis of carboxylic acids ranging from C2 to C18, in hydrogen peroxide solution. The addition of peracids with 4-8 carbons in their alkyl chains led to the formation of two regioisomers, with the prevalence of hydroxyesters bearing a primary free hydroxyl (4c-4e). This prevalence became more pronounced when peracids with longer alkyl chains (C10-C18) were used. In this case, only isomers 4f-4h were formed. The antioxidant activity of the resulting hydroxyesters was assessed by means of the conjugated autoxidizable triene (CAT) assay, and it was found out that the 4-vinyl guaiacol antioxidant activity was significantly increased by grafting alkyl chains with 2-8 carbons.
- Zago, Erika,Durand, Erwann,Barouh, Nathalie,Lecomte, Jér?me,Villeneuve, Pierre,Aouf, Chahinez
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- Rapid biosynthesis of phenolic glycosides and their derivatives from biomass-derived hydroxycinnamates
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Biomass-derived hydroxycinnamates (mainly includingp-coumaric acid and ferulic acid), which are natural sources of aromatic compounds, are highly underutilized resources. There is a need to upgrade them to make them economically feasible. Value-added phenolic glycosides and their derivatives, both belonging to a class of plant aromatic natural products, are widely used in the nutraceutical, pharmaceutical, and cosmetic industries. However, their complex aromatic structures make their efficient biosynthesis a challenging process. To overcome this issue, we created three novel synthetic cascades for the biosynthesis of phenolic glycosides (gastrodin, arbutin, and salidroside) and their derivatives (hydroquinone, tyrosol, hydroxytyrosol, and homovanillyl alcohol) fromp-coumaric acid and ferulic acid. Moreover, because the biomass-derived hydroxycinnamates directly provided aromatic units, the cascades enabled efficient biosynthesis. We achieved substantially high production rates (up to or above 100-fold enhancement) relative to the glucose-based biosynthesis. Given the ubiquity of the aromatic structure in natural products, the use of biomass-derived aromatics should facilitate the rapid biosynthesis of numerous aromatic natural products.
- Zhao, Mingtao,Hong, Xulin,Abdullah,Yao, Ruilian,Xiao, Yi
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p. 838 - 847
(2021/02/09)
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- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
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The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
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supporting information
p. 20042 - 20048
(2021/12/03)
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- 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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- Efficient synthesis of styrene derivatives through ethenolysis of renewable propenylbenzenes
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Functionalized styrenes were obtained by the ethenolysis of renewable 1-propenylbenzenes in a very efficient synthetic pathway. Some of the products are valuable food & flavor ingredients (4-vinylguaiacol) or locust pheromone (4-vinylanisole). The catalysts employed were ruthenium-alkylidene complexes bearing a N-heterocyclic carbene as a ligand, which bulkiness proved to be important for the catalysis output. The judicious choice the reaction conditions was critical to enable near quantitative yields under mild conditions in short reaction times. More strikingly, the catalyst load could be reduced to 0.01 mol%, keeping good conversion and selectivity.
- Avenda?o Villarreal, Jesus A.,Delolo, Fábio G.,Granato, Artur V.,dos Santos, Eduardo N.
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- The first one-pot metathesis-hydroformylation procedure: a straight synthesis of 2-arylpropanals from renewable 1-propenylbenzenes
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Hydroformylation is a consolidated synthetic tool in the chemical industry, both in commodity and in the fine chemicals industry. Olefin metathesis has been largely employed in the petrochemical sector, and, more recently, in the synthesis of specialty chemicals. Although these reactions may be involved in the same synthetic route for various industrial chemicals, to the best of our knowledge, they have never been combined in a one-pot procedure. As a proof of concept, we have demonstrated in the present work that the ruthenium-catalyzed ethenolysis of renewable 1-propenylbenzenes followed by the rhodium-catalyzed hydroformylation of functionalized styrenes formed in the first step could be done in one pot. The integration of these reactions was not straightforward once the catalyst of the first step interfered with the catalyst of the second step. Under optimized conditions, it was possible to synthesize 2-arylpropanals, a class of compounds valuable as synthetic intermediates to access non-steroidal anti-inflammatory drugs, in overall yields of 85-90%, at low catalyst loadings.
- Avenda?o Villarreal, Jesus Alberto,Delolo, Fábio Godoy,Granato, Artur Vicari,Gusevskaya, Elena Vitalievna,dos Santos, Eduardo Nicolau
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p. 8007 - 8013
(2021/12/27)
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- New hybrids based on curcumin and resveratrol: Synthesis, cytotoxicity and antiproliferative activity against colorectal cancer cells
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We synthesized twelve hybrids based on curcumin and resveratrol, and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated against SW480 human colon adenocarcinoma cells, its metastatic derivative SW620, along with the non-malignant CHO-K1 cell line. Among the tested compounds, hybrids 3e and 3i (for SW480) and 3a, 3e and 3k (for SW620) displayed the best cytotoxic activity with IC50 values ranging from 11.52 ± 2.78 to 29.33 ± 4.73 μM for both cell lines, with selectivity indices (SI) higher than 1, after 48 h of treatment. Selectivity indices were even higher than those reported for the reference drug, 5-fluorouracil (SI = 0.96), the starting compound resveratrol (SI = 0.45) and the equimolar mixture of curcumin plus resveratrol (SI = 0.77). The previous hybrids showed good antiproliferative activity.
- Cardona-G, Wilson,Hernández, Cristian,Herrera-R, Angie,Moreno, Gustavo
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- Cross-Coupling Reactions with 2-Amino-/Acetylamino-Substituted 3-Iodo-1,4-naphthoquinones: Convenient Synthesis of Novel Alkenyl- And Alkynylnaphthoquinones and Derivatives
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Functionalized 1,4-naphthoquinones have been employed as versatile synthons in organic synthesis, in addition to presenting a large array of biological activities. Herein, the applications of 2-amino-/ acetylamino-substituted 3-iodo-1,4-naphthoquinones in cross-coupling reactions are described to successfully afford sixteen novel 3-styryl-1,4-naphthoquinones (amino-stilbene-quinone hybrids) and four 3-alkynyl-1,4-naphthoquinone in overall good yields. Interestingly, the alkynylated derivatives could be obtained from ligand- and Pd-free Cu I -mediated cross-coupling reactions, after extensive investigations to exclude Pd as a co-catalyst. Lastly, the desilanized terminal alkyne was subjected to click chemistry reactions to give two novel triazole-1,4-naphthoquinone hybrids.
- Demidoff, Felipe C.,Rodrigues Filho, Eduardo José P.,De Souza, Andréa Luzia F.,Netto, Chaquip D.,De Carvalho, Leandro L.
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supporting information
p. 4097 - 4109
(2021/08/31)
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- Selective catalytic transformation of lignin with guaiacol as the only liquid product
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Guaiacol is an important feedstock for producing various high-value chemicals. However, the current production route of guaiacol relies heavily on fossil resources. Using lignin as a cheap and renewable feedstock to selectively produce guaiacol has great potential, but it is a challenge because of its heterogeneity and inert reactivity. Herein, we discovered that La(OTf)3 could catalyze the transformation of lignin with guaiacol as the only liquid product. In the reaction, La(OTf)3 catalyzed the hydrolysis of lignin ether linkages to form alkyl-syringol and alkyl-guaiacol, which further underwent decarbonization and demethoxylation to produce guaiacol with a yield of up to 25.5 wt%, and the remaining residue was solid. In the scale-up experiment, the isolated yield of guaiacol reached up to 21.2 wt%. To our knowledge, this is the first work to produce pure guaiacol selectively from lignin. The bio-guaiacol may be considered as a platform to promote lignin utilization.
- Shen, Xiaojun,Meng, Qinglei,Mei, Qingqing,Liu, Huizhen,Yan, Jiang,Song, Jinliang,Tan, Dongxing,Chen, Bingfeng,Zhang, Zhanrong,Yang, Guanying,Han, Buxing
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p. 1347 - 1352
(2020/02/15)
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- Structural features and antioxidant activities of Chinese quince (Chaenomeles sinensis) fruits lignin during auto-catalyzed ethanol organosolv pretreatment
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Chinese quince fruits (Chaenomeles sinensis) have an abundance of lignins with antioxidant activities. To facilitate the utilization of Chinese quince fruits, lignin was isolated from it by auto-catalyzed ethanol organosolv pretreatment. The effects of three processing conditions (temperature, time, and ethanol concentration) on yield, structural features and antioxidant activities of the auto-catalyzed ethanol organosolv lignin samples were assessed individually. Results showed the pretreatment temperature was the most significant factor; it affected the molecular weight, S/G ratio, number of β-O-4′ linkages, thermal stability, and antioxidant activities of lignin samples. According to the GPC analyses, the molecular weight of lignin samples had a negative correlation with pretreatment temperature. 2D-HSQC NMR and Py-GC/MS results revealed that the S/G ratios of lignin samples increased with temperature, while total phenolic hydroxyl content of lignin samples decreased. The structural characterization clearly indicated that the various pretreatment conditions affected the structures of organosolv lignin, which further resulted in differences in the antioxidant activities of the lignin samples. These results can be helpful for controlling and optimizing delignification during auto-catalyzed ethanol organosolv pretreatment, and they provide theoretical support for the potential applications of Chinese quince fruits lignin as a natural antioxidant in the food industry.
- Cheng, Xi-Chuang,Guo, Xin-Ran,Liu, Hua-Min,Liu, Yu-Lan,Qin, Zhao,Wang, Xue-De
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p. 4348 - 4358
(2020/09/22)
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- Selective hydrodeoxygenation of hydroxyacetophenones to ethyl-substituted phenol derivatives using a FeRu?SILP catalyst
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The selective hydrodeoxygenation of hydroxyacetophenone derivatives is achieved opening a versatile pathway for the production of valuable substituted ethylphenols from readily available substrates. Bimetallic iron ruthenium nanoparticles immobilized on an imidazolium-based supported ionic liquid phase (Fe25Ru75?SILP) show high activity and stability for a broad range of substrates without acidic co-catalysts. This journal is
- Bordet, Alexis,Goclik, Lisa,Leitner, Walter,Offner-Marko, Lisa
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supporting information
p. 9509 - 9512
(2020/09/02)
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- Monitoring hydroxycinnamic acid decarboxylation by lactic acid bacteria using high-throughput UV-Vis spectroscopy
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Hydroxycinnamic acid (HCA) decarboxylation by lactic acid bacteria (LAB) results in the production of 4-vinylplenols with great impact on the sensorial characteristics of foods. The determination of LAB decarboxylating capabilities is key for optimal strain selection for food production. The activity of LAB strains from the Ohio State University-Parker Endowed Chair (OSU-PECh) collection potentially capable of synthesizing phenolic acid decarboxylase was evaluated after incubation with HCAs for 36 h at 32 °C. A high-throughput method for monitoring HCAs decarboxylation was developed based on hypsochromic shifts at pH 1.0. Out of 22 strains evaluated, only Enterococcus mundtii, Lactobacillus plantarum and Pediococcus pentosaceus were capable of decarboxylating all p-coumaric, caffeic and ferulic acids. Other strains only decarboxylated p-coumaric and caffeic acid (6), only p-coumaric acid (2) or only caffeic acid (1), while 10 strains did not decarboxylate any HCA. p-Coumaric acid had the highest conversion efficiency, followed by caffeic acid and lastly ferulic acid. Results were confirmed by HPLC-DAD-ESI-MS analyses, showing the conversion of HCAs into their 4-vinylphenol derivatives. This work can help improve the sensory characteristics of HCA-rich foods where fermentation with LAB was used during processing.
- García-Cano, Israel,Giusti, M. Monica,Jiménez-Flores, Rafael,Miyagusuku-Cruzado, Gonzalo,Rocha-Mendoza, Diana
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- One-pot Cu/TiO2 nanoparticles synthesis for trans-ferulic acid conversion into vanillin
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In this study, the co-synthesis of TiO2 and Cu metallic nanoparticles obtained via one-pot cost-efficient hydrothermal process has been addressed. Different nanocatalysts with Cu contents were characterized by X-ray diffraction, nitrogen porosimetry, scanning electron microscopy, and transmission electron microscopy. The TiO2 and Cu metallic nanoparticles were synthesized with copper loading up to one (Cu/Ti atomic ratio). Synthesized catalysts exhibited pore sizes in the mesoporous range and high surface areas above 150 m2/g. The particle size for TiO2 presented a homogeneous distribution of approximately 8 nm, moreover, Cu nanoparticles varied from 12 to >100 nm depending on the metal loading. The nanostructured materials were successfully tested in the conversion of trans-ferulic acid into vanillin under sustainable conditions, achieving the best performance for 0.3 Cu/Ti atomic ratio (70% vanillin yield).
- Gómez-López, Paulette,Lázaro, Noelia,Alvarado-Beltrán, Clemente G.,Pineda, Antonio,Balu, Alina M.,Luque, Rafael
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- Comprehensive kinetic and substrate specificity analysis of an arylsulfatase from Helix pomatia using mass spectrometry
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Sulfatases hydrolyze sulfated metabolites to their corresponding alcohols and are present in all domains of life. These enzymes have found major application in metabolic investigation of drugs, doping control analysis and recently in metabolomics. Interest in sulfatases has increased due to a link between metabolic processes involving sulfated metabolites and pathophysiological conditions in humans. Herein, we present the first comprehensive substrate specificity and kinetic analysis of the most commonly used arylsulfatase extracted from the snail Helix pomatia. In the past, this enzyme has been used in the form of a crude mixture of enzymes, however, recently we have purified this sulfatase for a new application in metabolomics-driven discovery of sulfated metabolites. To evaluate the substrate specificity of this promiscuous sulfatase, we have synthesized a series of new sulfated metabolites of diverse structure and employed a mass spectrometric assay for kinetic substrate hydrolysis evaluation. Our analysis of the purified enzyme revealed that the sulfatase has a strong preference for metabolites with a bi- or tricyclic aromatic scaffold and to a lesser extent for monocyclic aromatic phenols. This metabolite library and mass spectrometric method can be applied for the characterization of other sulfatases from humans and gut microbiota to investigate their involvement in disease development.
- Correia, Mário S.P.,Ballet, Caroline,Meistermann, Hannes,Conway, Louis P.,Globisch, Daniel
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p. 955 - 962
(2019/02/09)
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- Bio-based vinylphenol family: Synthesis via decarboxylation of naturally occurring cinnamic acids and living radical polymerization for functionalized polystyrenes
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A series of bio-based vinylphenols or hydroxystyrenes is prepared by simple decarboxylation of various naturally occurring cinnamic acids such as o-, m-, and p-coumaric; caffeic; ferulic; and sinapinic acids, which possess hydroxy groups and other substituents at different positions on the aromatic ring. After protection of the phenolic moieties with trialkylsilyl groups, reversible addition–fragmentation chain-transfer polymerization is accomplished with cumyl dithiobenzoate to afford various bio-based hydroxyl-protected polystyrenes with controlled molecular weights and narrow molecular weight distributions. Subsequent deprotection of the silyl groups under mild conditions results in a series of well-defined functionalized polystyrenes possessing different numbers (mono-, di-, tri-) of hydroxy groups at different positions (o, m, p). The obtained functionalized polystyrenes show unique thermal properties depending on the substituents, and those with phenol and catechol groups serve as reducing agents for silver ions.
- Takeshima, Hisaaki,Satoh, Kotaro,Kamigaito, Masami
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- Copper-Catalyzed Oxidative Difunctionalization of Terminal Unactivated Alkenes
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The copper(II)-promoted free-radical oxidative difunctionalization of terminal alkenes to access ketoazides by utilizing molecular oxygen has been reported. A series of styrene derivatives have been evaluated and were found to be compatible to give the desired difunctionalized products in moderate to good yields. The role of molecular oxygen both as an oxidant and oxygen atom source in this catalytic transformation has been unquestionably demonstrated by 18O-labeling studies and a radical mechanistic pathway involving the oxidative formation of azidyl radicals is also designed. This environment-friendly catalytic oxidative protocol can transform aldehyde to nitrile.
- Hussain, Muhammad Ijaz,Feng, Yangyang,Hu, Liangzhen,Deng, Qingfu,Zhang, Xiaohui,Xiong, Yan
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p. 7852 - 7859
(2018/05/30)
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- Synthesis and antiproliferative activity of 3- and 7-styrylcoumarins
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A series of styrylcoumarins were obtained via Mizoroki-Heck reactions between 3-bromo-4-methyl-7-(octyloxy)-2H-chromen-2-one or 2-oxo-2H-chromen-7-yl trifluoromethanesulfonate and functionalized styrenes. The structures of the products were elucidated by spectroscopic analysis. All compounds were evaluated against SW480 and CHO-K1 cell lines. A number of hybrids showed good antiproliferative activity. Among the tested compounds, hybrids 6e, 10c, and 10d, exhibited the highest activity (IC50- SW480/48h = 6,92; 1,01 and 5,33 μM, respectively) and selectivity (IS48h = >400; 67,8 and 7,2, respectively). In addition, these compounds were able to preserve their activities over time. The results achieved by these hybrids were even better than the lead compounds (coumarin and resveratrol) and the standard drug (5-FU). As regards structure-activity relationship it seems that the location of the styryl group on the coumarin structure and the presence of the hydroxyl group on the phenyl ring were determinant for the activity.
- Herrera-R, Angie,Castrillón, Wilson,Otero, Elver,Ruiz, Esneyder,Carda, Miguel,Agut, Raúl,Naranjo, Tonny,Moreno, Gustavo,Maldonado, Maria Elena,Cardona-G, Wilson
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p. 1893 - 1905
(2018/06/25)
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- Multienzyme One-Pot Cascade for the Stereoselective Hydroxyethyl Functionalization of Substituted Phenols
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The operability and substrate scope of a redesigned vinylphenol hydratase as a single biocatalyst or as part of multienzyme cascades using either substituted coumaric acids or phenols as stable, cheap, and readily available substrates are reported.
- Payer, Stefan E.,Pollak, Hannah,Schmidbauer, Benjamin,Hamm, Florian,Juri?i?, Filip,Faber, Kurt,Glueck, Silvia M.
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supporting information
p. 5139 - 5143
(2018/09/13)
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- Terminal Alkenes from Acrylic Acid Derivatives via Non-Oxidative Enzymatic Decarboxylation by Ferulic Acid Decarboxylases
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Fungal ferulic acid decarboxylases (FDCs) belong to the UbiD-family of enzymes and catalyse the reversible (de)carboxylation of cinnamic acid derivatives through the use of a prenylated flavin cofactor. The latter is synthesised by the flavin prenyltransferase UbiX. Herein, we demonstrate the applicability of FDC/UbiX expressing cells for both isolated enzyme and whole-cell biocatalysis. FDCs exhibit high activity with total turnover numbers (TTN) of up to 55000 and turnover frequency (TOF) of up to 370 min?1. Co-solvent compatibility studies revealed FDC's tolerance to some organic solvents up 20 % v/v. Using the in-vitro (de)carboxylase activity of holo-FDC as well as whole-cell biocatalysts, we performed a substrate profiling study of three FDCs, providing insights into structural determinants of activity. FDCs display broad substrate tolerance towards a wide range of acrylic acid derivatives bearing (hetero)cyclic or olefinic substituents at C3 affording conversions of up to >99 %. The synthetic utility of FDCs was demonstrated by a preparative-scale decarboxylation.
- Aleku, Godwin A.,Prause, Christoph,Bradshaw-Allen, Ruth T.,Plasch, Katharina,Glueck, Silvia M.,Bailey, Samuel S.,Payne, Karl A. P.,Parker, David A.,Faber, Kurt,Leys, David
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p. 3736 - 3745
(2018/08/03)
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- Development and scaling-up of the fragrance compound 4-ethylguaiacol synthesis via a two-step chemo-enzymatic reaction sequence
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The transformation of (abundant) oxygenated biomass-derived building blocks via chemo-enzymatic methods is a valuable concept for accessing useful compounds, as it combines the high selectivity of enzymes and the versatility of chemical catalysts. In this work, we demonstrate a straightforward combination of a phenolic acid decarboxylase (PAD) and palladium on charcoal (Pd/C) that affords the flavor compound 4-ethylguaiacol from ferulic acid. The use of a two-phase system proved to be advantageous in terms of enzyme activity, stability, and volumetric productivity and allows us to carry out the hydrogenation step directly in the organic layer containing exclusively the intermediate, vinylguaiacol. The enzymatic decarboxylation step in the biphasic system afforded 89% conversion of 100 mM (19 g L-1) ferulic acid with an isolated yield of 75%. By extracting 4- vinylguaiacol continuously into the organic phase, conversion was enhanced to 92% using 170 mM (33 g L-1) ferulic acid, which was only possible in the continuous extraction and distillation setup developed. The reaction cascade (PAD-Pd/C) is demonstrated at gram scale, affording the target product 4-ethylguaiacol (1.1 g) in 70% isolated yield in a two-step two-pot process. The enzymatic step was characterized in detail to overcome major constraints, and the process favorably compares in terms of the environmental impact with traditional approaches.
- Pesci, Lorenzo,Baydar, Maik,Glueck, Silvia,Faber, Kurt,Liese, Andreas,Kara, Selin
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- Selective Oxidation of Aromatic Olefins Catalyzed by Copper(II) Complex in Micellar Media
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Abstract: The selective oxidation of aromatic olefins 1,2-dimethoxy-4-vinylbenzene (DEVB) and 2-methoxy-4-vinylphenol (MOVP) by H2O2 into 1-(3,4-dime-thoxyphenyl)ethanol (MVA) and 1-(4-hydroxy-3-methoxyphenyl)ethanol (HMOPE) catalyzed by copper(II) complex CuL (L = 6,8,15,17-tetramethyl-7,16-dihydrodibenzo-1,4,8,11-tetraazacyclotetradecine) were achieved in cationic surfactant cetyl trimethylammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS) and nonionic surfactant Triton X-100 (TX-100) micellar media, respectively. Micelle showed great influence on both reaction rate and selectivity of product. Aromatic olefins could be oxidized into corresponding aromatic ketones in aqueous solution, but into secondary alcohols in micellar media. The combination of TEMPO and CuL/H2O2 resulted in relatively fast reaction rate and S > 96% selectivity of aromatic ketones. The reaction rate constants, k1, k2 and k3 for three oxidation reactions pathways: olefin to ketone, olefin to alcohol and alcohol to ketone were obtained, respectively. The kinetic study indicated that the CuL catalyzed oxidation of olefins by H2O2 to alcohols was a relatively rapid and major reaction and ketone was generated by the direct oxidation of olefins, not by further oxidation of alcohol in micellar media. Graphical Abstract: [Figure not available: see fulltext.].
- Li, Xiao-Hong,Mi, Chun,Liao, Xiao-Hong,Meng, Xiang-Guang
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p. 2508 - 2514
(2017/09/06)
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- Synthesis of Stilbene-Quinone Hybrids through Heck Reactions in PEG-400
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Styrenes were coupled with 3-iodolawsone in PEG-400 at 90 °C, leading stereoselectively to (E)-stilbene-quinone hybrids through Heck reactions. The best reaction conditions were found to be the use of NaOH (3 equiv) and 10 mol% of palladium acetate at 90 °C for 15 minutes. The chemical yields of the Heck reactions using styrenes with electron-withdrawing groups (65-98%) were greater than styrenes bearing electron-donating groups (7-32%) on the aromatic ring. In particular, the chemical yields of Heck reactions involving nitrostyrenes were the best ones observed.
- Demidoff, Felipe C.,De Souza, Fabrícia P.,Netto, Chaquip D.
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supporting information
p. 5217 - 5223
(2017/11/28)
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- Efficient synthesis of functionalized olefins by Wittig reaction using Amberlite resin as a mild base
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A convenient procedure for the synthesis of olefins by the reaction of stabilized, semistabilized, and nonstabilized phosphorous ylides with various aldehydes or ketone using Amberlite resin as a mild base is described. Our developed method offers facile and racemization-free synthesis of α,β-unsaturated amino esters and chiral allylic amine. The developed methodology offers mild reaction conditions, high efficiency, and facile isolation of the final products, a practical alternative to known procedures.
- Valkute, Tushar R.,Aratikatla, Eswar K.,Bhattacharya, Asish K.
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p. 581 - 589
(2017/03/15)
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- Method for manufacturing styrene derivative
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PROBLEM TO BE SOLVED: To provide a method of simply producing a styrene derivative with high yield using a reagent which is relatively cheap and easily removed, and relatively mild condition.SOLUTION: A production method of a styrene derivative comprises a step of decarboxylating a derivative of hydroxycinnamic acid in a solvent containing at least one kind of amide bond-containing solvent, in the presence of water and/or a hydroxy group-containing compound.
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Paragraph 0067
(2018/10/16)
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- Switching the Cleavage Sites in Palladium on Carbon-Catalyzed Carbon-Carbon Bond Disconnection
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We have demonstrated a palladium on carbon-catalyzed approach to regioselectively alter the cleavage sites of the C-C bonds of cinnamaldehyde derivatives by a slight change in the reaction conditions in isopropanol under an O2 atmosphere. Styrene derivatives could be selectively formed by the addition of Na2CO3 in association with the dissociation of carbon monoxide, while benzaldehyde derivatives were generated by the addition of CuCl and morpholine instead of Na2CO3. (Chemical Equation Presented).
- Hattori, Tomohiro,Takakura, Ryoya,Ichikawa, Tomohiro,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
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p. 2737 - 2743
(2016/04/26)
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- Synthesis of bio-based epoxy monomers from natural allyl- and vinyl phenols and the estimation of their affinity to the estrogen receptor α by molecular docking
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Diepoxydized diphenyls from eugenol, 4-vinyl guaiacol and 4-vinyl syringol (canolol) were synthesized as sustainable alternatives to the diglycidyl ether of bisphenol A (DGEBA). In the first step, glycidylated derivatives were produced by reaction with epichlorohydrin. Then, the dimerization of these derivatives was performed by cross metathesis (CM) reaction in the presence of the Grubbs II catalyst. From the CM reaction, a set of epoxy phenolic dimers was obtained in good yields with a high diastereoselectivity. Estimation by molecular docking calculations of the affinity of the synthesized products and their hydrolysed structures to the intranuclear estrogen receptor ERα showed that the epoxy forms presented a moderate affinity to the antagonistic conformation of the receptor (six to forty times lower than bisphenol A and in the same order of magnitude as DGEBA) and mostly no binding in the agonist conformation. The hydrolysed forms of the epoxy products, which are expected to be predominant in the human body cells, exhibited a relatively weak affinity to the ERα LBD in its both agonistic and antagonistic conformations.
- Zago, Erika,Dubreucq, Eric,Lecomte, Jér?me,Villeneuve, Pierre,Fine, Frédéric,Fulcrand, Hélène,Aouf, Chahinez
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p. 7701 - 7710
(2016/09/12)
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- CSJ acting as a versatile highly efficient greener resource for organic transformations
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Simple, new, greener and efficient alternatives to the existing protocols have been developed for the reduction of aromatic aldehydes to their corresponding alcohols, decarboxylation of substituted benzoic acids (C6-C1) and substituted cinnamic acids (C6-C3) with a hydroxyl group at the para position with respect to the acid group to corresponding phenolic compounds and vinyl phenols respectively by using a natural feedstock, cucumber juice (CSJ), which acts as a greener solvent system, performing a substrate-selective reaction. Additionally, the hydrolysis of the acetyl as well as the benzoyl group of aromatic compounds has been carried out to afford excellent yield by CSJ.
- Maity, Himadri Sekhar,Misra, Kaushik,Mahata, Tanushree,Nag, Ahindra
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p. 24446 - 24450
(2016/03/15)
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- A One-Pot Cascade Reaction Combining an Encapsulated Decarboxylase with a Metathesis Catalyst for the Synthesis of Bio-Based Antioxidants
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The combination of enzymes with traditional chemical catalysts unifies the high selectivity of the former with the versatility of the latter. A major challenge of this approach is the difference in the optimal reaction conditions for each catalyst type. In this work, we combined a cofactor-free decarboxylase with a ruthenium metathesis catalyst to produce high-value antioxidants from bio-based precursors. As suitable ruthenium catalysts did not show satisfactory activity under aqueous conditions, the reaction required the use of an organic solvent, which in turn significantly reduced enzyme activity. Upon encapsulation of the decarboxylase in a cryogel, the decarboxylation could be conducted in an organic solvent, and the recovery of the enzyme after the reaction was facilitated. After an intermediate drying step, the subsequent metathesis in pure organic solvent proved to be straightforward. The synthetic utility of the cascade was demonstrated by the synthesis of the antioxidant 4,4′-dihydroxystilbene in an overall yield of 90 %.
- Gómez Baraibar, álvaro,Reichert, Dennis,Mügge, Carolin,Seger, Svenja,Gr?ger, Harald,Kourist, Robert
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supporting information
p. 14823 - 14827
(2016/11/23)
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- Isofunctional enzymes PAD1 and UbiX catalyze formation of a novel cofactor required by ferulic acid decarboxylase and 4-hydroxy-3-polyprenylbenzoic acid decarboxylase
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The decarboxylation of antimicrobial aromatic acids such as phenylacrylic acid (cinnamic acid) and ferulic acid by yeast requires two enzymes described as phenylacrylic acid decarboxylase (PAD1) and ferulic acid decarboxylase (FDC). These enzymes are of interest for various biotechnological applications, such as the production of chemical feedstocks from lignin under mild conditions. However, the specific role of each protein in catalyzing the decarboxylation reaction remains unknown. To examine this, we have overexpressed and purified both PAD1 and FDC from E. coli. We demonstrate that PAD1 is a flavin mononucleotide (FMN)-containing protein. However, it does not function as a decarboxylase. Rather, PAD1 catalyzes the formation of a novel, diffusible cofactor required by FDC for decarboxylase activity. Coexpression of FDC and PAD1 results in the production of FDC with high levels cofactor bound. Holo-FDC catalyzes the decarboxylation of phenylacrylic acid, coumaric acid and ferulic acid with apparent kcat ranging from 1.4-4.6 s-1. The UV-visible and mass spectra of the cofactor indicate that it appears to be a novel, modified form of reduced FMN; however, its instability precluded determination of its structure. The E. coli enzymes UbiX and UbiD are related by sequence to PAD1 and FDC respectively and are involved in the decarboxylation of 4-hydroxy-3-octaprenylbenzoic acid, an intermediate in ubiquinone biosynthesis. We found that endogenous UbiX can also activate FDC. This implies that the same cofactor is required for decarboxylation of 4-hydroxy-3-polyprenylbenzoic acid by UbiD and suggests a wider role for this cofactor in metabolism.
- Lin, Fengming,Ferguson, Kyle L.,Boyer, David R.,Lin, Xiaoxia Nina,Marsh, E. Neil G.
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p. 1137 - 1144
(2015/07/07)
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- Selective oxidative cleavage of terminal olefins into aldehydes catalyzed by copper(II) complex
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A simple method for oxidative C=C bond cleavage of terminal olefins to aldehydes with H2O2 catalyzed by copper(II) complex LCu consisted of copper(II) and macrocyclic ligand 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene (L) was described. This study indicated that the copper(II) complex displayed excellent catalytic ability for the selective oxidation of terminal olefins to aldehydes with high selectivity (S > 90%) in CH3CN at 30 °C. The possible catalytic reaction mechanism of oxidation of terminal olefins was discussed.
- Mi, Chun,Meng, Xiang-Guang,Liao, Xiao-Hong,Peng, Xiao
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p. 69487 - 69492
(2015/09/01)
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- Preparation of functional styrenes from biosourced carboxylic acids by copper catalyzed decarboxylation in PEG
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A general protocol for the copper-catalyzed decarboxylation of α,β-unsaturated carboxylic acids in PEG, particularly of biosourced cinnamic acid analogues, is reported. Moderate to high isolated yields (31-96%) towards the styrene derivatives were obtained. For the first time, decarboxylation of α-amino acids to the corresponding amines was successfully performed with good to high yields and extended to the decarboxylation of a few condensed heterocyclic compounds. Both the use of PEG as a green solvent and direct separation of the pure product of the reaction by distillation permitted the reuse of the solvent and the Cu-based catalytic system over several cycles without deactivation. This was extended to the synthesis of 4-vinylguaiacol on the laboratory scale in an average 92% yield. This journal is the Partner Organisations 2014.
- Cadot, Stephane,Rameau, Nelly,Mangematin, Stephane,Pinel, Catherine,Djakovitch, Laurent
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supporting information
p. 3089 - 3097
(2014/06/10)
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- Correlating lignin structural features to phase partitioning behavior in a novel aqueous fractionation of softwood Kraft black liquor
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In this work, a set of softwood lignins were recovered from a Kraft black liquor using a novel pH-based fractionation process involving sequential CO 2 acidification and separation of the solvated aqueous lignin fraction. These recovered lignin fractions were characterized with respect to properties that may be responsible for their phase partitioning behavior as well as properties that may render the lignins more suitable for materials applications. Lignin fractions were recovered between a pH range of 12.8 and 9.5 with the bulk of the lignin (90%) recovered between a pH of 11.1 and 10.0. While all the fractions were found to consist primarily of lignin as validated by sample methoxyl content, the first fractions to phase separated were found to be especially enriched in aliphatic extractives and polysaccharides. From the bulk of the lignin that was recovered between a pH of 11.1 and 10.0 a number of noteworthy trends were discernible from the data. Specifically, the phenolic hydroxyl content was found to exhibit a strong negative correlation to the fractionation pH and exhibited a nearly 50% increase with recovery at decreasing pH, while the GPC-estimated molecular weights and 13C NMR-estimated β-O-4 content showed strong positive correlations to the pH at recovery. The aliphatic hydroxyl content exhibited minimal differences between recovery conditions. Overall, these results suggest that this fractionation approach can generate lignin fractions enriched in select physical or structural properties that may be important for their application as feedstocks for renewable chemicals or materials.
- Stoklosa, Ryan J.,Velez, Julian,Kelkar, Shantanu,Saffron, Christopher M.,Thies, Mark C.,Hodge, David B.
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supporting information
p. 2904 - 2912
(2013/10/08)
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- Isomerizing ethenolysis as an efficient strategy for styrene synthesis
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A shrinking chain: A bimetallic system consisting of [{Pd(μ-Br)(tBu 3P)}2] and a ruthenium metathesis catalyst has been found to efficiently promote the cross-metathesis between substituted alkenes and ethylene, while continuously migrating the double bond along the alkenyl chain (see scheme). When alkenylarenes, such as the natural products eugenol, safrol, or estragol, were treated with this catalyst under an ethylene atmosphere, they were cleanly converted into the corresponding styrenes and propylene gas. Copyright
- Baader, Sabrina,Ohlmann, Dominik M.,Goossen, Lukas J.
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supporting information
p. 9807 - 9810
(2013/08/23)
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- Resveratrol derived butyrylcholinesterase inhibitors
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Novel polyhydroxylated (E)-stilbenes were synthesized by Mizoroki-Heck reactions and tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them are good inhibitors of butyrylcholinesterase; one of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase. Novel polyhydroxylated (E)-stilbenes synthesized by Mizoroki-Heck reactions were tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them were found to be good inhibitors of butyrylcholinesterase. One of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase.
- Csuk, Rene,Albert, Sabrina,Kluge, Ralph,Stroehl, Dieter
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p. 499 - 503
(2013/07/26)
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- Synthesis and radical scavenging activities of resveratrol analogs
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Highly substituted polyhydroxylated (E)-stilbenes were synthesized by Mizoroki-Heck reactions and tested for their ability to act as radical scavenger. One of the 56 stilbenes included in this study and investigated in DPPH assays gave an SC50 value of 11.0 μM, hence exhibiting an about 9.3 times higher activity than resveratrol. As shown in a photometric SRB assay using mouse NiH 3T3 fibroblasts, this compound is not cytotoxic up to concentrations of 30 μM. Highly substituted polyhydroxylated (E)-stilbenes synthesized by Mizoroki-Heck reactions were tested for their ability to act as radical scavengers. One of the 56 stilbenes included exhibited about 9.3 times higher activity than resveratrol. At concentrations 30 μM, this compound was not cytotoxic.
- Csuk, Rene,Albert, Sabrina,Siewert, Bianka
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p. 504 - 510
(2013/07/26)
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- Structural characterization of lignin isolated from coconut (Cocos nucifera) coir fibers
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The structure of the isolated milled wood lignin from coconut coir has been characterized using different analytical methods, including Py-GC/MS, 2D NMR, DFRC, and thioacidolysis. The analyses demonstrated that it is a p-hydroxyphenyl-guaiacyl-syringyl (H-G-S) lignin, with a predominance of G units (S/G ratio 0.23) and considerable amounts of associated p-hydroxybenzoates. Two-dimensional NMR indicated that the main substructures present in this lignin include β-O-4′ alkyl aryl ethers followed by phenylcoumarans and resinols. Two-dimensional NMR spectra also indicated that coir lignin is partially acylated at the γ-carbon of the side chain with p-hydroxybenzoates and acetates. DFRC analysis showed that acetates preferentially acylate the γ-OH in S rather than in G units. Despite coir lignin's being highly enriched in G-units, thioacidolysis indicated that β-β′ resinol structures are mostly derived from sinapyl alcohol. Finally, we find evidence that the flavone tricin is incorporated into the coconut coir lignin, as has been recently noted for various grasses.
- Rencoret, Jorge,Ralph, John,Marques, Gisela,Gutiérrez, Ana,Martínez, ángel T.,Del Río, José C.
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p. 2434 - 2445
(2013/05/09)
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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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- DEPOLYMERIZATION OF LIGNIN USING SOLID ACID CATALYSTS
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The invention provides for a process for the depolymerization of lignin in an inert atmosphere to result in substituted phenolic monomer compounds. The process is catalysed by heterogeneous solid acid catalysts and is carried out in batch or continuous mode.
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Page/Page column 6; 7
(2012/12/13)
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- ONE POT MULTICOMPONENT SYNTHESIS OF SOME NOVEL HYDROXY STILBENE DERIVATIVES WITH ALPHA, BETA-CARBONYL CONJUGATION UNDER MICROWAVE IRRADIATION
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The present invention provides a method for the preparation of some novel multiconjugated 2- or 4-hydroxy substituted stilbenes. The method provides one pot multicomponent approach wherein 3-4 step reaction sequences viz. condensation, decarboxylation and Heck coupling occur simultaneously which results in an enhanced yield of desired products and reduced reaction times
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Page/Page column 6
(2012/07/13)
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- New greener alternatives for bioreduction of aromatic aldehydes and decarboxylation of aromatic acids using juice of fruits
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Cocos nucifera L. and Borassus flabellifer L. juices act as bio catalytic system for the reduction of aromatic aldehydes to alcohols and selective decarboxylation of substituted cinnamic acid to styrene and substituted benzoic acid to polyphenolic compound. Both juices exhibit good activity when aromatic aldehydes and aromatic acids contain electron-donating groups at specific positions. Moreover, C. nucifera juice exhibits good result for the reduction and decarboxylation properties than B. flabellifer juice under the same reaction condition.
- Misra, Kaushik,Maity, Himadri Sekhar,Chanda, Subhankar,Nag, Ahindra
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experimental part
p. 92 - 95
(2012/09/22)
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- Aromas Kit
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An Aromas kit uses containers of certain discrete molecules to provide odors suitable for an olfactory education of wine properties. The disclosed molecules may be found within certain wines and provide a useful olfactory reference when smelling a finished wine sample, even when the wine sample contains a myriad of other conflicting or competing molecule smells.
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- Pd-catalyzed orthogonal Knoevenagel/Perkin condensation-decarboxylation- heck/Suzuki sequences: Tandem transformations of benzaldehydes into hydroxy-functionalized antidiabetic stilbene-cinnamoyl hybrids and asymmetric distyrylbenzenes
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Tandem reactions that involve chemoselective Knoevenagel/Perkin condensation-decarboxylation-Heck/Suzuki coupling or Heck-aldol sequences have been achieved. This enabled the first concise and efficient synthesis of several important hydroxy-functionalized compound classes, such as stilbene-cinnamoyl hybrids (potent protein tyrosine phosphatase1B inhibitors), cinnamoyl-cinnamic acid hybrids, asymmetric distyrylbenzenes, and biarylstyrenes. Previously reported synthesis require multiple steps and protection/deprotection manipulations.
- Sharma, Naina,Sharma, Abhishek,Shard, Amit,Kumar, Rakesh,Saima,Sinha, Arun K.
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body text
p. 10350 - 10356
(2011/10/12)
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- Synthesis and biological evaluation of isosteric analogs of mandipropamid for the control of oomycete pathogens
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A series of isosteric analogs of mandipropamid were designed and synthesized via 'click chemistry'. The amide bond of mandipropamid was substituted by a 1,2,3-triazole functional group. The bioassay results have indicated that some of the title compounds exhibited moderate fungicidal activity against Pseudoperonospora cubensis, and the activity has been systematically studied as a function of molecular structure. The low activity of the mandipropamid analog that contains a lipid chain is likely due to the presence of a weak hydrogen bond donor in the 1,2,3-triazole. Furthermore, we have performed the molecular modeling and found that N-methylamide could be more effective than amide as the surrogates to 1,2,3-triazole, which ultimately leads to a longer distance (1.1A longer) between the two substitutes in the 1,4-disubstituted 1,2,3-triazole compound.
- Su, Na,Wang, Zhen-Jun,Wang, Li-Zhong,Zhang, Xiao,Dong, Wei-Li,Wang, Hong-Xue,Li, Zheng-Ming,Zhao, Wei-Guang
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scheme or table
p. 101 - 111
(2012/06/01)
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- Antioxidant properties of 4-vinyl derivatives of hydroxycinnamic acids
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The compounds 4-vinylphenol (4-VP), 4-vinylguaiacol (4-VG), 4-vinylsyringol (4-VS) and 4-vinylcatechol (4-VC) were prepared by thermal decarboxylation of the corresponding hydroxycinnamic acids p-coumaric, ferulic, sinapic and caffeic acid, respectively. For confirmation of the synthesised products LC-MS followed by NMR analysis was used. To evaluate their antioxidant potential, their reducing power and efficiency in scavenging the alkylperoxyl radical generated in an emulsion system, the 2,2-diphenyl-1-picrylhydrazyl (DPPH ·) radical and the superoxide anion radical (O2-) were determined. All tested 4-vinyl derivatives revealed weaker antioxidant activity in a homogeneous polar medium than the corresponding phenolic acids. In the emulsion system the activity for 4-vinyl derivatives was higher than was the activity of their corresponding phenolic acids, with 4-VG as the most active among the tested phenolic compounds.
- Terpinc, Petra,Polak, Toma?,?egatin, Nata?a,Hanzlowsky, Andrej,Ulrih, Nata?a Poklar,Abramovi?, Helena
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experimental part
p. 62 - 69
(2012/03/22)
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- Photoisomerization of ionic liquid ammonium cinnamates: One-pot synthesis-isolation of Z-cinnamic acids
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Photoisomerization presents the only direct method for contra-thermodynamic E-Z isomerization of olefins. Synthetic applications of this method have been limited by its reversible nature, which leads to a photostationary-state mixture of both isomers. For the first time, a highly efficient one-pot preparation-isolation of solid ionic liquid Z-cinnamic acids by photoisomerization in acetonitrile solution of ionic liquid E-cinnamic acids is described.
- Salum, Maria L.,Robles, Cecilia J.,Erra-Balsells, Rosa
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supporting information; experimental part
p. 4808 - 4811
(2011/01/03)
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