- Isolation and identification of a potent radical scavenger (canolol) from roasted high erucic mustard seed oil from nepal and its formation during roasting
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Roasting of high erucic mustard (HEM) seed has been reported to give a typical flavor and increase the oxidative stability of the extracted oil. A potent radical scavenging compound was successfully isolated from roasted HEM seed oil in a single-step chromatographic separation using an amino solid-phase extraction column. Nuclear magnetic resonance and mass spectrometry spectra revealed the compound as 2,6-dimethoxy-4-vinylphenol (generally known as canolol), and its identity was fully confirmed by chemical synthesis. The formation of canolol during roasting was compared among HEM varieties (Brassica juncea, B. juncea var. oriental, Brassica nigra, and Sinapis alba) together with a low erucic rapeseed variety. HEM varieties were shown to produce less than one-third of canolol compared to rapeseed at similar roasting conditions. This observation was linked to a lower free sinapic acid content together with a lower loss of sinapic acid derivatives in the HEM varieties compared to rapeseed. Around 50% of the canolol formed in the roasted seed was shown to be extracted in the oil. Roasting of HEM seed before oil extraction was found to be a beneficial step to obtain canolol-enriched oil, which could improve the oxidative stability.
- Shrestha, Kshitij,Stevens, Christian V.,De Meulenaer, Bruno
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- Antioxidant canolol production from a renewable feedstock via an engineered decarboxylase
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Canolol (4-vinylsyringol, VS), a potent antioxidant and an alkylperoxyl radical scavenger originally discovered in crude canola oil (rapeseed), is produced by decarboxylation of sinapic acid (SA) during canola seed roasting. Chemical syntheses of VS from SA require thermal or microwave induced decarboxylation in the presence of a base. A laboratory-evolved enzyme, designated SA decarboxylase (SAD), was developed in this study. In a biphasic bioreactor system, SAD was shown to produce VS from SA extracts prepared from canola meal with an overall yield of 3.0 mg VS per g of canola meal. In addition, we investigated the application of VS in polymerization to produce polyvinylsyringol (PVS) as a potential biodegradable polymer. The characteristics of PVS determined by thermogravimetric analysis, differential scanning calorimetry and nanoindentation tests are described.
- Morley, Krista L.,Grosse, Stephan,Leisch, Hannes,Lau, Peter C. K.
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- Production of canolol from canola meal phenolics via hydrolysis and microwave-induced decarboxylation
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A potent antioxidant, anti-inflammatory and anti-mutagenic agent; 4-vinyl-2,6-dimethoxyphenol (canolol) was obtained from canola meal in a significant yield via alkaline (NaOH)/enzymatic (ferulic acid esterase) hydrolysis followed by microwave-assisted decarboxylation. The hydrolysis was carried out either through using canola meal directly as a substrate or by using the 70 % aqueous methanolic extract filtrates. The hydrolyzed extracts underwent RP-HPLC analysis which showed that 81.0 and 94.8 % of the total phenolics were hydrolyzed to sinapic acid after the alkaline hydrolysis of the meal and the methanolic extracts, respectively. The enzymatic hydrolysis showed lower conversion rates (49.5 and 58.3 %). The hydrolyzed extracts were consequently decarboxylated using 8-diazabicyclo[5.4.0]undec-7-ene under microwave irradiation at different conditions. The HPLC profiling of decarboxylated extracts showed that using microwave at 300 Wof microwave power for 12 min brought the highest sinapic acid conversion to canolol (58.3 %) yielding 4.2 mg canolol from each gram of canola meal suggesting that the process could be commercially economical. AOCS 2013.
- Khattab, Rabie Y.,Eskin, Michael N.A.,Thiyam-Hollander, Usha
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- Studies on the key aroma compounds in raw (unheated) and heated japanese soy sauce
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An investigation using the aroma extract dilution analysis (AEDA) technique of the aroma concentrate from a raw Japanese soy sauce and the heated soy sauce revealed 40 key aroma compounds including 7 newly identified compounds. Among them, 5(or 2)-ethyl-4-hydroxy-2(or 5)-methyl-3(2H)-furanone and 3-hydroxy-4,5-dimethyl-2(5H)-furanone exhibited the highest flavor dilution (FD) factor of 2048, followed by 3-(methylthio)propanal, 4-ethyl-2-methoxyphenol, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone having FD factors from 128 to 512 in the raw soy sauce. Furthermore, comparative AEDAs, a quantitative analysis, and a sensory analysis demonstrated that whereas most of the key aroma compounds in the raw soy sauce were common in the heated soy sauce, some of the Strecker aldehydes and 4-vinylphenols contributed less to the raw soy sauce aroma. The model decarboxylation reactions of the phenolic acids during heating of the raw soy sauce revealed that although all reactions resulted in low yields, the hydroxycinnamic acid derivatives were much more reactive than the hydroxybenzoic acid derivatives due to the stable reaction intermediates. Besides the quantitative analyses of the soy sauces, the estimation of the reaction yields of the phenolic compounds in the heated soy sauce revealed that although only the 4-vinylphenols increased during heating of the raw soy sauce, they might not mainly be formed as decarboxylation products from the corresponding hydroxycinnamic acids but from the other proposed precursors, such as lignin, shakuchirin, and esters with arabinoxylan.
- Kaneko, Shu,Kumazawa, Kenji,Nishimura, Osamu
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- Antioxidant activity of soybean oil containing 4-vinylsyringol obtained from decarboxylated sinapic acid
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4-Vinylsyringol was produced by decarboxylation from sinapic acid. To evaluate the antioxidant activity of 4-vinylsyringol, 500 ppm of 4-vinylsyringol, sinapic acid, or α-tocopherol was added to soybean oil and the oxidation processes were monitored by the peroxide value (PV), the thiobarbituric acid reactive substances value (TBARS) assay, and 1H-NMR spectroscopy. The results obtained by PV and TBARS indicated that soybean oil containing 4-vinylsyringol (SBO-VS) showed the highest oxidative stability. 1H-NMR analysis also showed concurring results. After 19 days of oxidation, the degradation rates of linoleic acid (4.2 %) and linolenic acid (4.4 %) in SBO-VS were significantly lower than those in other oils. Secondary oxidation products (i.e. aldehydes) were undetectable in SBO-VS by 1H NMR, whereas concentrations of such compounds in soybean oils containing α-tocopherol or sinapic acid were 38.0 ± 0.4 and 2.75 ± 0.2 mM oil, respectively. In addition, synergistic antioxidant effect between any two antioxidants was not observed.
- Wang, Xiang-Yu,Yang, Dan,Jia, Cai-Hua,Shin, Jung-Ah,Hong, Soon Taek,Lee, Ki-Teak,Zhang, Hua,Lee, Yong-Hwa,Jang, Young-Seok
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- Isolation, identification, and structure of a potent alkyl-peroxyl radical scavenger in crude canola oil, canolol
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Alkylhydroperoxides in oxidized oil are undesirable components because they become alkylperoxyl radicals (ROO?) in the presence of heme, hemoglobin, or myoglobin in red meat. ROO? are biochemically reactive and damage nucleic acids and proteins, thereby harming living cells. We isolated a component, a highly potent ROO? scavenger, from crude canola oil (rapeseed), which we designated canolol, and identified its chemical structure, 4-vinyl-2,6-dimethoxyphenol. The canolol content of crude canola oil greatly increased after the seed was roasted as compared with that from unroasted seed, but it decreased in highly purified oil. This anti-ROO? activity was highest in crude oil, deceased after each refining step, and was lowest in highly purified refined oil. Canolol was thus generated during roasting. As shown previously, canolol is one of the most potent anti-ROO? components in crude canola oil and its potency is much greater than that of well-known antioxidants, including α-tocopherol, vitamin C, β-carotene, rutin, and quercetin.
- Wakamatsu, Daisuke,Morimura, Shigeru,Sawa, Tomohiro,Kida, Kenji,Nakai, Chiaki,Maeda, Hiroshi
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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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- A kinetic approach in the evaluation of radical-scavenging efficiency of sinapic acid and its derivatives
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A kinetic approach was used to determine the radical scavenging activities of sinapic acid and its derivatives: sinapine, 4-vinylsyringol, syringic acid, syringaldehyde, and ethyl, propyl and butyl sinapate. The responses were expressed as rates of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging (RS), superoxide radical (O2-) scavenging (RFF), and β-carotene bleaching in the emulsion system (RB). For RS and RB, the esters of sinapic acid showed the highest responses while, for RFF, this was seen for syringic acid. The effectiveness of the selected compounds for scavenging these free radicals was also determined at a fixed endpoint. The early response parameters were demonstrated to be good discriminators in assessing differences for antioxidants with comparable fixed endpoint activity. The primary feature that ranks the kinetic data and the endpoint determinations is interpreted in terms of the mechanisms of the reactions involved in each of the assays conducted.
- Niciforovi?, Neda,Polak, Toma?,Makuc, Damjan,Ulrih, Nata?a Poklar,Abramovic, Helena,McPhee, Derek J.
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- Photoacid-Enabled Synthesis of Indanes via Formal [3 + 2] Cycloaddition of Benzyl Alcohols with Olefins
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An environmentally friendly and highly diastereoselective method for synthesizing indanes has been developed via a metastable-state photoacid system containing catalytic protonated merocyanine (MEH). Under visible-light irradiation, MEH yields a metastable spiro structure and liberated protons, which facilitates the formation of carbocations from benzyl alcohols, thus delivering diverse molecules in the presence of various nucleophiles. Mainly, a variety of indanes could be easily obtained from benzyl alcohols and olefins, and water is the only byproduct.
- Yang, Biao,Dong, Kui,Li, Xiang-Sheng,Wu, Li-Zhu,Liu, Qiang
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supporting information
p. 2040 - 2044
(2022/03/17)
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- Amino Group Functionalized Hf-Based Metal-Organic Framework for Knoevenagel-Doebner Condensation
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A Hf(IV) metal-organic framework (MOF) with di-amino functionalized linker was obtained as a crystalline solid with UiO-67 topology under solvothermal reaction conditions. The guest free form of Hf(IV) MOF (1′) was efficiently employed as a heterogeneous catalyst to synthesize cinnamic acid derivatives via Knoevenagel-Doebner reaction for the first time. The catalyst (1′) was efficiently active to directly achieve cinnamic acid from benzaldehyde and malonic acid. The solid retained its activity up to 6th cycle with no decay in its activity. The noticeable advantages of the catalyst are its milder reaction conditions, high yield, high stability, recyclable nature towards catalysis and wide substrate scope as well as shape-selective behaviour. The possible mechanism of the reaction was also studied thoroughly with suitable control experiments.
- Das, Aniruddha,Anbu, Nagaraj,Gogoi, Chiranjib,Dhakshinamoorthy, Amarajothi,Biswas, Shyam
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p. 3396 - 3403
(2021/08/20)
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- Profiling of the formation of lignin-derived monomers and dimers from: Eucalyptus alkali lignin
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Lignin is a renewable and the most abundant aromatic source that can be used for extensive chemicals and materials. Although approximately 50 million tons of lignin are produced annually as a by-product of the pulp and paper industry, it is currently underutilized. It is important to know the structural features of technical lignin when considering its application. In this work, we have demonstrated the formation of low-molecular-weight constituents from hardwood (Eucalyptus) lignin, which produces much more low-molecular-weight constituents than softwood (spruce) lignin, after a chemical pulping process, and analyzed the micromolecular compositions in the alkali lignin after fractionation by dichloromethane (DCM) extraction. By applying analytical methods (gel-permeation chromatography, 2D NMR and GC-MS) with the aid of evidence from authenticated compounds, a great treasure trove of lignin-derived phenolic compounds from Eucalyptus alkali lignin were disclosed. Except for some common monomeric products, as many as 15 new lignin-derived monomers and dimers including syringaglycerol, diarylmethane, 1,2-diarylethanes, 1,2-diarylethenes, (arylvinyl ether)-linked arylglycerol dimers and isomeric syringaresinols were identified in the DCM-soluble fraction. Regarding the formation and evolution of the Cα-condensed β-aryl ether structure, a novel route that is potentially responsible for the high content of β-1 diarylethenes and diarylethanes in the lignin low-molecular-weight fraction, in addition to the β-1 (spirodienone) pathway, was proposed. This work not only provides novel insights into the chemical transformation of S-G lignin during the alkali pulping process, but also discovered lignin-derived phenolic monomers and dimers that can potentially be used as raw materials in the chemical or pharmaceutical industries. This journal is
- Hu, Zhenhua,Li, Suxiang,Lu, Fachuang,Shi, Lanlan,Wang, Chen,Yue, Fengxia,Zhang, Han,Zhao, Chengke
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supporting information
p. 7366 - 7375
(2020/11/18)
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- METHOD OF SELECTIVELY OXIDIZING LIGNIN
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A method of selectively reacting lignin or a lignin-derived reactant to yield an aromatic product. The method includes the step of reacting lignin or a lignin-derived reactant with a molybdenum-containing catalyst, in a solvent, and optionally in the presence of an oxidant, for a time and a temperature wherein at least a portion of the lignin or lignin-derived reactant is selectively converted into an aromatic product, preferably coniferaldehyde and/or sinapaldehyde.
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Paragraph 0022
(2019/06/20)
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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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- Selective oxidation of lignin model compounds
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Lignin, the planet’s most abundant renewable source of aromatic compounds, is difficult to degrade efficiently to well-defined aromatics. We developed a microwave-assisted catalytic Swern oxidation system using an easily prepared catalyst, MoO2Cl2(DMSO)2, and DMSO as the solvent and oxidant. It demonstrated high efficiency in transforming lignin model compounds containing the units and functional groups found in native lignins. The aromatic ring substituents strongly influenced the selectivity of β-ether phenolic dimer cleavage to generate sinapaldehyde and coniferaldehyde, monomers not usually produced by oxidative methods. Time-course studies on two key intermediates provided insight into the reaction pathway. Owing to the broad scope of this oxidation system and the insight gleaned with regard to its mechanism, this strategy could be adapted and applied in a general sense to the production of useful aromatic chemicals from phenolics and lignin.
- Gao, Ruili,Li, Yanding,Kim, Hoon,Mobley, Justin K.,Ralph, John
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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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- 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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- 4 - hydroxystyrene compound separation method (by machine translation)
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[Problem] 4 - hydroxystyrene polymer does not contain volatile components produced by reaction a compound, 4 - hydroxystyrene separation method for obtaining high-purity of a compound. [Solution] 4 - hydroxystyrene compound, in the presence of a volatile solvent and a non-volatile solvent by distillation-thin, highly pure 4 - hydroxystyrene compound preparation can be obtained. The resulting formulation is stable with time, and can be applied to various applications and uses. [Drawing] no (by machine translation)
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Paragraph 0021
(2017/06/20)
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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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- Synthesis of 4-vinylsyringol from sinapic acid using sodium acetate trihydrate catalyst in ethanol system
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The present invention relates to a synthesis method of 4-vinylsyringol comprising a step of conducting decarboxylation by adding sinapic acid and a catalyst to ethanol. The synthesis method of the present invention can obtain toxic-free 4-vinylsyringol under moderate reaction conditions, and can be safely used to food, medicine, cosmetic products, etc.COPYRIGHT KIPO 2016
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Paragraph 0021-0024
(2017/06/23)
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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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- Thiol-ene "click" reaction triggered by neutral ionic liquid: The "ambiphilic" character of [hmim]br in the regioselective nucleophilic hydrothiolation
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Thiol-ene "click" chemistry has emerged as a powerful strategy to construct carbon-heteroatom (C-S) bonds, which generally results in the formation of two regioisomers. To this end, the neutral ionic liquid [hmim]Br has been explored as a solvent cum catalyst for the synthesis of linear thioethers from activated and inactivated styrene derivatives or secondary benzyl alcohols and thiols without the requirement of using a metal complex, base, or free radical initiator. Furthermore, detailed mechanistic investigations using 1H NMR spectroscopy and quadrupole time-of-flight electrospray ionization mass spectrometry (Q-TOF ESI-MS) revealed that the "ambiphilic" character of the ionic liquid promotes the nucleophilic addition of thiol to styrene through an anti-Markovnikov pathway. The catalyst recyclability and the extension of the methodology for thiol-yne click chemistry are additional benefits. A competitive study among thiophenol, styrene, and phenyl acetylene revealed that the rate of reaction is in the order of thiol-yne a?a thiol-ene a?a dimerization of thiol in [hmim]Br.
- Kumar, Rajesh,Saima,Shard, Amit,Andhare, Nitin H.,Richa,Sinha, Arun K.
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supporting information
p. 828 - 832
(2015/02/05)
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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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- 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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- Asymmetric enzymatic hydration of hydroxystyrene derivatives
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More than one activity: Owing to their hydratase activity, phenolic acid decarboxylases catalyze the regio- and stereoselective addition of H 2O across the C=C double bond of hydroxystyrene derivatives yielding (S)-4-(1-hydroxyethyl)phenols with up to 82 % conversion and 71 % ee. Based on structure analysis and molecular docking simulations, a catalytic mechanism for this novel enzymatic reaction is proposed. Copyright
- Wuensch, Christiane,Gross, Johannes,Steinkellner, Georg,Gruber, Karl,Glueck, Silvia M.,Faber, Kurt
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supporting information
p. 2293 - 2297
(2013/04/10)
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- Regioselective enzymatic carboxylation of phenols and hydroxystyrene derivatives
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The enzymatic carboxylation of phenol and styrene derivatives using (de)carboxylases in carbonate buffer proceeded in a highly regioselective fashion: Benzoic acid (de)carboxylases selectively formed o-hydroxybenzoic acid derivatives, phenolic acid (de)carboxylases selectively acted at the β-carbon atom of styrenes forming (E)-cinnamic acids.
- Wuensch, Christiane,Glueck, Silvia M.,Gross, Johannes,Koszelewski, Dominik,Schober, Markus,Faber, Kurt
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supporting information; experimental part
p. 1974 - 1977
(2012/06/15)
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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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- 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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- Obtaining 4-vinylphenols by decarboxylation of natural 4-hydroxycinnamic acids under microwave irradiation
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4-Vinylphenols, useful compounds for industrial applications, were obtained by decarboxylation of 4-hydroxycinnamic acids under microwave irradiation in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base and basic aluminum oxide as solid support. The reactions were fast (15-30 min). The selective extraction of the final products with ethyl acetate avoids chromatographic purifications. The conversions are quantitative and the yields are satisfactory. Only the unstable 4-vinylcatechol was obtained in moderate yield. This procedure was successfully extended to a natural sample of ferulic acid extracted from wheat bran to get the corresponding 4-vinylguaiacol, a FEMA GRAS (Flavor and Extract Manufacturer's Association; General Regarded as Safe) approved flavoring agent.
- Bernini, Roberta,Mincione, Enrico,Barontini, Maurizio,Provenzano, Gianfranco,Setti, Leonardo
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p. 9663 - 9667
(2008/02/11)
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- One-pot two-step synthesis of 4-vinylphenols from 4-hydroxy substituted benzaldehydes under microwave irradiation: a new perspective on the classical Knoevenagel-Doebner reaction
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The classical Knoevenagel-Doebner reaction is reinvestigated wherein the direct synthesis of substituted 4-vinylphenols instead of the expected 4-hydroxycinnamic acids is described. The condensation reaction is performed on 4-hydroxy substituted benzaldehydes and malonic acid with a mixture of acetic acid-piperidine as condensing agent under focused microwave irradiation. The occurrence of simultaneous condensation-double decarboxylation without the use of any decarboxylating agent is a new finding, the reaction being facilitated solely by the hydroxy substituent and microwave irradiation effect.
- Sinha, Arun K.,Sharma, Anuj,Joshi, Bhupendra P.
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p. 960 - 965
(2007/10/03)
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- Methoxyphenols from burning of Scandinavian forest plant materials
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Semivolatile compounds in smoke from gram-scale incomplete burning of plant materials were assessed by gas chromatography and mass spectrometry. Gas syringe sampling was shown to be adequate by comparison with adsorbent sampling. Methoxyphenols as well as 1,6-anhydroglucose were released in amounts as large as 10 mg kg-1 of dry biomass at 90% combustion efficiency. Wood, twigs, bark and needles from the conifers Norway spruce and Scots pine emitted 12 reported 2-methoxyphenols in similar proportions. Grass, heather and birchwood released the same 2-methoxyphenols but also the corresponding 2,6-dimethoxyphenols which are characteristic of angiosperms. The methoxyphenols are formed from lignin and differ in structure by the group in para position relative to the phenolic OH group. Prominent phenols were those with trans-l-propenyl and ethenyl groups in that position. Vanillin, 4- hydroxy-3-methoxybenzaldehyde, was a prominent carbonyl compound from the conifer materials. (C) 2000 Elsevier Science Ltd.
- Kjaellstrand, Jennica,Ramnaes, Olle,Petersson, Goeran
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p. 735 - 741
(2007/10/03)
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