- CINNAMAMIDE DERIVATIVES FROM CLAUSENA LANSIUM
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From the ether extract of the seeds of Clausena lansium, three new amide derivatives have been isolated, and their structures elucidated by chemical and spectroscopic methods.They were shown to be N-cis-styryl-cinnamamide, N-methyl-N-cis-styryl-cinnamamide and N-methyl-N-phenethyl-cinnamamide, which we have named lansiumamides A, B and C, respectively.In addition, a known amide, lansamide-I was identified. - Keywords: Clausena lansium; Rutaceae; cinnamamide; lansiumamides; lansamide-I; cinnamic acid derivative.
- Lin, Jer-Huei
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- A Rapid and Efficient Microwave-Assisted Synthesis of Substituted 3-Phenylpropionic Acids from Benzaldehydes in Minutes
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A convenient, inexpensive, and efficient synthesis of 3-phenylpropionic acids (1a-1f) by reacting benzaldehyde (2a-2f) and malonic acid in acetic acid and piperidine into cinnamic acid (3a-3f) in 77 to 89% followed by its reduction with PdCl2 in the biphase of formic acid and aqueous sodium hydroxide is reported under microwave irradiation which utilizes short reaction time ranging 5 to 7 min to provide 1a-1f in moderate to high yield (69-86%) depending upon methoxy, methylenedioxy, and hydroxy groups present at the phenyl ring.
- Sharma, Anuj,Joshi, Bhupendra P.,Sinha, Arun K.
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- Batatins I and II, ester-type dimers of acylated pentasaccharides from the resin glycosides of sweet potato
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Batatins I (1) and II (2), two ester-type dimers of acylated pentasaccharides, have been isolated by recycling HPLC from the hexane-soluble extract of sweet potato (Ipomoea batatas var. batatas). The structures were elucidated by a combination of high-resolution NMR spectroscopy and mass spectrometry. Complete analysis and unambiguous assignments of the 1H and 13C NMR spectra of 1 and 2 were achieved by 2D shift correlation measurements. The glycosidic acid forming each branched pentasaccharide monomelic unit was confirmed as simonic acid B. Three different fatty acids esterify this core at the same positions in both batatins: C-2 on the second rhamnose unit and C-4 and C-2 (or C-3) on the third rhamnose moiety. The acylating residues were identified as (+)-(2S)-methylbutanoic, dodecanoic (lauric), and cinnamic acids. The site of lactonization by the aglycon in unit A was placed at C-3 of the second saccharide. The position for the ester linkage for monomelic unit B on the macrocylic unit A was identified as C-3 of the terminal rhamnose?. Through spectroscopic simulation of these complex oligosaccharides, the chemical shifts and coupling constants were deduced for the overlapped proton resonances with a non-first-order resolution. The experimental NMR spectroscopic values registered for batatinoside I (3), a new polyacylated macroyclic pentasaccharide also isolated from this plant, were used as the starting point for spectral simulation of 1 and 2. Both polymers 1 and 2 represent dimers of compound 3.
- Escalante-Sanchez, Edgar,Pereda-Miranda, Rogelio
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- Nickel-mediated regio- and chemoselective carboxylation of alkynes in the presence of carbon dioxide
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Alkynes are carboxylated in a highly regio- and chemoselective manner in the presence of Ni(cod)2, DBU, and CO2 to give the carboxylated products in good yields. The reaction was carried out under very mild conditions (CO2 1 atm, 0°C) in the presence of a stoichiometric amount of alkynes, conjugated enynes, or diynes. The high selectivity observed in the reaction would be explained in terms of the stability and the reactivity of the intermediates.
- Saito, Shinichi,Nakagawa, Satomi,Koizumi, Toru,Hirayama, Kyoko,Yamamoto, Yoshinori
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- Alkylacylimidazoles in Claisen–Schmidt and Knoevenagel Condensations
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Abstract: Alkylacylimidazoles were shown to be good reagents for Claisen–Schmidt and Knoevenagel-like condensations. The Claisen–Schmidt condensation of N-acetylimidazole with benzaldehyde followed by acidification with HCl gave cinnamic acid. The Knoevenagel-like condensation of N-(acetoacetyl)imidazole with hydrated aldehydes resulted in a fast and efficient formation of β-hydroxyketones. The studied reactions provide a new and general synthetic approach to cinnamic acid derivatives and β-hydroxyketones, as well as a new application field of alkylacylimidazoles.
- Mei, X.,Ning, J.,Quan, H.,She, D.,Wang, L.,Wang, Zh.
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- New iridoid glycoside from Gratiola officinalis
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A new iridoid glycoside, 1β,6β-di-O-trans-cinnamoyl-9-O-β-D- glucopyranosyl-3-iridene-5β-ol (1), along with four known compounds loliolide (2), β-sitosterol-3-O-β-D-glucopyranoside (3), betulinic acid (4), and β-amyrin (5), was isolated from the aerial parts of Gratiola officinalis L. The structure of the new compound was deduced on the basis of 1D 1H and 13C NMR and 2D HMQC, HMBC, and COSY experiments, and mass spectrometric techniques (EI-MS and HR-EI-MS). The relative configuration of 1 was assigned by comparative analysis of the NMR spectral data with known analogs, together with NOESY experiments.
- Ali, Liaqat,Rizvi, Tania Shamim,Ahmad, Manzoor,Shaheen, Farzana
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- An Equilibrium Study of the Conversion of L-Phenylalanine to trans-Cinnamic Acid and Ammonia
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The thermodynamics of the enzymatic conversion (L-phenylalanine ammonia-lyase) of aqueous L-phenylalanine to trans-cinnamic acid and ammonia has been investigated by using high-performance liquid chromatography (HPLC).The reaction was carried out in 0.1 M Tris/HCl buffer containing ammonium chloride over the pH range 7.0-7.7, at ionic strength from 1.0 to 2.1 mol kg-1, and over the temperature range 285-316 K.Analysis of the HPLC data using an estimated heat capacity change of 50 J mol-1 K-1 and an ion-size parameter of 1.6 mol-1/2 kg1/2 leads to an equilibrium constant of 1.16 +/- 0.3 mol kg-1 and an enthalpy change of 24.8 +/- 2.0 kJ mol-1 at 298.15 K for the process L-phenylalanine+/-(aq) = trans-cinnamic acid-(aq) + NH4+(aq).The use of these thermodynamic parameters in an equilibrium model for this system allows for the prediction of values of the apparent equilibrium constant as a function of pH, temperature, and composition and also of the effect of these parameters on the optimal product yield of L-phenylalanine during its manufacture from trans-cinnamic acid and ammonia.The available thermochemical data for this generic type of reaction can be rationalized in terms of a scheme which views the entropy changes for related processes to be comparable and then attributes differences in Gibbs energy changes to differences in enthalpy changes which can be influenced by effects such as resonance stabilization of the double bonds which are formed.
- Tewari, Yadu B.,Gajewsi, Ewa,Goldberg, Robert N.
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- Solid-supported reagents for the oxidation of aldehydes to carboxylic acids
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Solid-supported reagents such as phosphate-buffered (PB) silica gel (SiO2) supported potassium permanganate (KMnO4) and polymer-supported (PS) chlorite have been prepared and used in the conversion of aldehydes to carboxylic acids, affording products without any need for conventional work-up procedures.
- Takemoto,Yasuda,Ley
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- Highly regioselective Friedel-Crafts alkylation of indoles with α,β-unsaturated N-acylbenzotriazoles
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The Friedel-Crafts alkylation rather than acylation of indoles was realized with α,β-unsaturated acylbenzotriazoles catalyzed by samarium(III) iodide under reflux in anhydrous THF. The reaction was highly regioselective, and a series of new 3-substituted indole derivatives were obtained in moderate to good yields with the potential to be further transformed into various indole derivatives due to the presence of active acylbenzotriazole moiety.
- Zou, Xuefei,Wang, Xiaoxia,Cheng, Cungui,Kong, Lichun,Mao, Hui
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- "Fishing and hunting"-selective immobilization of a recombinant phenylalanine ammonia-lyase from fermentation media
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This article overviews the numerous immobilization methods available for various biocatalysts such as whole-cells, cell fragments, lysates or enzymes which do not require preliminary enzyme purification and introduces an advanced approach avoiding the costly and time consuming downstream processes required by immobilization of purified enzyme-based biocatalysts (such as enzyme purification by chromatographic methods and dialysis). Our approach is based on silica shell coated magnetic nanoparticles as solid carriers decorated with mixed functions having either coordinative binding ability (a metal ion complexed by a chelator anchored to the surface) or covalent bond-forming ability (an epoxide attached to the surface via a proper linker) enabling a single operation enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag.
- Sánta-Bell, Evelin,Molnár, Zsófia,Varga, Andrea,Nagy, Flóra,Hornyánszky, Gábor,Paizs, Csaba,Balogh-Weiser, Diána,Poppe, László
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- Simulating microwave chemistry in a resistance-heated autoclave made of semiconducting silicon carbide ceramic
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"Microwave chemistry" without microwaves: A resistance-heated SiC autoclave can effectively mimic the sealed-vessel capabilities, rapid heating and cooling profiles, and excellent process-control features that are inherent to modern microwave reactors. Applied to synthetic chemistry, the ready-to-assemble small device provides identical results as can be obtained in a (costly) microwave system (see figure). Copyright
- Obermayer, David,Damm, Markus,Kappe, C. Oliver
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- C-C-VERKNUEPFUNG VON ALKENEN MIT CO2 AN NICKEL(0); HERSTELLUNG VON ZIMTSAEURE AUS STYROL
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Styrene undergose a 1/1 oxidative coupling reaction with CO2 and (Lig)Ni0 systems to give two oxanickelacyclopentanones.Depending on the temperature the formation of cinnamic acid is observed in high yield.
- Hoberg, Heinz,Peres, Yolande,Milchereit, Armin
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- Epoxide and hydroperoxide derived from naturally cinnamaldehyde and its Schiff base derivatives
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Thermal and photo epoxidation, photooxygenation reactions of cinnamaldehyde may be useful tool for the design of drugs to act as potent chemopreventation and anticancer agents. trans-Cinnamaldehyde was isolated from essential oil of cinnamon ( Cinnamonum verum). It was subjected to oxidation reactions either photochemically with hydrogen peroxide or thermally with 3-chloro-peroxybenzoic acid. Schiff base derivative was synthesized through condensation reaction with aniline. It subjected to photooxidation reaction in the presence of tetraphenylporphin as singlet oxygen sensitizer. photochemically oxidation reaction gave the corresponding epoxy derivative together with cis-isomerisation. Whereas, thermally oxidation reaction resulted the corresponding epoxy derivative together with cinnamic acid. In addition, photooxidation reaction of Schiff base derivative led to 1-phenyl-3-phenyliminopropen-1-yl hydroperoxide through endoperoxide derivative. The primary tested of hydroperoxide derivative showed a moderate degree of DNA degradation. trans-Cinnamaldehyde and its derivatives can act as antioxidants. They were trapped the reactive oxygen species (ROS) to give the intermediated epoxides and hydroperoxide derivatives, which could be alkylated or damage DNA, proteins and other biological species
- Elgendy, Eman M.,Khayyat, Suzan A.
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- Cinnamic acid derivatives via heck reaction in an aqueous-biphasic catalytic system with easy catalyst-product separation
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A true biphasic [aqueous-organic] system for the coupling of water soluble sodium acrylate with different aryl halides for the synthesis of cinnamic acid derivatives has been developed, employing palladium catalysts that is soluble in organic phase. Amongst them, palladacycle was found to be stable in presence of water and could be recycled for four times with no loss in the activity. Such a system facilitates easy recycle of catalyst and also the removal of the salts from the catalyst phase, ensuring high activity with respect to cumulative turn over number (TON) and turn over frequency (TOF). The reaction was facilitated by organic as well as inorganic bases. The efficiency of the catalyst, role of organic/inorganic bases on the activity is reported.
- Jagtap,Deshpande
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- A new cyclododeca[d]oxazole derivative from Streptomyces spp. CIBYL1
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A novel secondary metabolite, N-trans-cinnamoyl 2-amino-3a,4,5,6,7,8,9,10, 11,12,13,13a-dodecahydrocyclododeca[d]oxazole (1), was isolated from Streptomyces spp. CIBYL1, along with five known compounds, pimprinine (2), (3R,4S,5R,6R)-3,4,5,6-tetrahydro-4-hydroxy-3,5,6-trimethyl-2H-pyran-2-one (3), indolyl-3-carboxylic acid (4), 2-phenylacetamide (5) and di(1H-pyrrol-2-yl) methanone (6). The structures of these metabolites were elucidated on the basis of extensive analysis of spectroscopic data, including OR, IR, HRMS, 1D and 2D NMR data and chemical derivation.
- Pu, Xiang,Li, Guangzhou,Yang, Tao,Li, Guoyou,Yi, Jinhai,Zhang, Guolin,Luo, Yinggang
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- Transcriptome-wide identification and characterization of Ornithogalum saundersiae phenylalanine ammonia lyase gene family
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OSW-1 is a promising antitumor glycoside present in the Ornithogalum saundersiae plant. Biosynthesis of the p-methoxybenzoyl group on the disaccharide moiety of OSW-1 is known to take place biochemically by phenylpropanoid biosynthetic pathway, but molecular biological characterization of related genes has been insufficient. Phenylalanine ammonia lyase (PAL, EC 4.3.1.24), which catalyzes the deamination of l-phenylalanine to yield trans-cinnamic acid, plays a key role in phenylpropanoid metabolism. Thus, the study on the characterization of the genes involved in the OSW-1 biosynthetic pathway, particularly the well-documented genes such as PAL, is essential to further the understanding of the biosynthesis of OSW-1. Here, transcriptomic sequencing of O. saundersiae was performed to speed up the identification of a large number of genes related to OSW-1 biosynthesis. De novo assembly of the transcriptome sequence provided 210733 contigs, 104, 180 unigenes, and four unigenes showing high similarities with PALs. Two full-length cDNAs encoding PALs (OsaPAL2 and OsaPAL62) from O. saundersiae were cloned using sequence information from these four unigenes. The PAL and tyrosine ammonia lyase (TAL) activities of recombinant OsaPAL proteins were unambiguously determined by HPLC with UV and MS detection as well as by NMR spectroscopy. Subsequently, a series of site-directed mutants were generated with the aim of improving enzyme activity and investigating the importance of particular residues in determining substrate selectivity. The results reveal that the Phe-to-His mutants, i.e., OsaPAL2F134H and OsaPAL62F128H, exhibited higher TAL activity than the corresponding wild types, providing direct evidence that the Phe residue is responsible for substrate specificity. Mutagenesis studies also demonstrated that the Thr-to-Ser mutants, i.e., OsaPAL2T196S and OsaPAL62T194S, showed significantly higher substrate affinity than the wild types. Furthermore, the Gly-to-Ala mutants, i.e., OsaPAL2G209A and OsaPAL62G207A, showed higher PAL and TAL activities. These findings provide further insight into the genes responsible for OSW-1 biosynthesis and will facilitate the future application of OsaPALs in synthetic biology.
- Wang, Zhi-Biao,Chen, Xi,Wang, Wei,Cheng, Ke-Di,Kong, Jian-Qiang
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- In Situ Metabolism of Cinnamyl Alcohol in Reconstructed Human Epidermis: New Insights into the Activation of This Fragrance Skin Sensitizer
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Chemical modification of epidermal proteins by skin sensitizers is the molecular event which initiates the induction of contact allergy. However, not all chemical skin allergens react directly as haptens with epidermal proteins but need either a chemical (prehaptens) or metabolic (prohaptens) activation step to become reactive. Cinnamyl alcohol has been considered a model prohapten, as this skin sensitizer has no intrinsic reactivity. Therefore, the prevailing theory is that cinnamyl alcohol is enzymatically oxidized into the protein-reactive cinnamaldehyde, which is the sensitizing agent. Knowing that reconstructed human epidermis (RHE) models have been demonstrated to be quite similar to the normal human epidermis in terms of metabolic enzymes, use of RHE may be useful to investigate the in situ metabolism/activation of cinnamyl alcohol, particularly when coupled with high-resolution magic angle spinning nuclear magnetic resonance. Incubation of carbon-13 substituted cinnamyl derivatives with RHE did not result in the formation of cinnamaldehyde. The metabolites formed suggest the formation of an epoxy-alcohol and an allylic sulfate as potential electrophiles. These data suggest that cinnamyl alcohol is inducing skin sensitization through a route independent of the one involving cinnamaldehyde and should therefore be considered as a skin sensitizer on its own.
- Moss, Eric,Debeuckelaere, Camille,Berl, Valérie,Elbayed, Karim,Moussallieh, Fran?ois-Marie,Namer, Izzie-Jacques,Lepoittevin
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- Supported nanosized palladium on superparamagnetic composite microspheres as an efficient catalyst for Heck reaction
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A magnetically separable palladium catalyst has been easily synthesized by immobilizing palladium nanoparticles on the surface of superparamagnetic composite microspheres. It can promote Heck cross-coupling reactions efficiently without an inert atmosphere. The novel catalyst can be conveniently recovered by applying a permanent magnet externally and reused at least six times without significant loss of its catalytic activity.
- Yuan, Dingzhong,Zhang, Qiuyu,Dou, Jinbo
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- High fluorine content bis(fluoro-ponytailed) bipyridine palladium complexes as catalyst for Mizoroki-Heck reactions under fluorous biphasic catalysis conditions
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Two highly fluorinated bipyridine derivatives, (4,4′-bis(R fCH2OCH2)-2,2′-bpy) {Rf = n-C10F21 (1a), n-C10F23 (1b)}, have been synthesized starting from 4,4′-bis(BrCH2)-2,2′-bpy and the corresponding fluorinated alkoxides. The fluorine contents of ligands 1a-b are 62.3% and 63.3%, respectively, both being white solids, virtually insoluble in CH2Cl2 or DMF and highly fluorophilic with a partition ratio between DMF and n-C8F18 less than 1:1000. The reaction of ligands 1a-b with [Pd(CH3CN)2Cl 2] results in novel Pd complexes [PdCl2(4,4′-bis- (RfCH2OCH2)-2,2′-bpy)] where R f = n-C10F21 (2a), n-C10F 23 (2b), respectively. The Pd complexes 2a-b are pale yellow solids, soluble only in fluorinated solvents. The Pd complexes 2a-b have been satisfactorily tested for Mizoroki-Heck arylation under fluorous biphasic catalysis conditions in that the Pd complexes 2a-b are easily recovered and maintain good catalytic activity after 8 consecutive cycles (> 90% yield). The TGA studies indicate that the Pd complexes 2a-b are thermally stable up to 300°C.
- Lu, Norman,Chen, Shih-Chieh,Lin, Yan-Chou,Cheng, Yao-Yi,Liu, Ling-Kang
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- Revised mechanism and improved methodology for the Perkin condensation. Resuscitation of the mechanism involving benzal acetate and the improbability of the enolate of acetic anhydride
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The Perkin condensation most likely occurs via the initial formation of a gem-diacetate from the aromatic aldehyde and acetic anhydride reactants. The key reactive nucleophile appears to be the enolate of the gem-diacetate rather than of acetic anhydride. The diacetate from PhCHO may be converted to cinnamic acid under a variety of (relatively) mild basic conditions.
- Chandrasekhar, Sosale,Karri, Phaneendrasai
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- Synthesis and transformations of 5-substituted 2-aryl-7H-[1,2,4]triazolo[3, 2-b][1,3]thiazin-7-ones and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a] benzimidazol-4-ones
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3-Aryl-1,2,4-triazole-5-thiones react with dimethyl acetylenedicarboxylate and methyl 3-phenyl-propynoate to afford the corresponding 5-substituted 2-aryl-7H-[1,2,4]triazolo[3,2-b][1,3]thiazin-7-ones. Treatment of 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones with alkalies leads to formation of 3-(benzimidazol-2-ylsulfanyl)-3-arylpropionic acids, their reaction with methyl p-toluenesulfonate yields 1-(3-methyl-2-thioxo-2,3- dihydro-1N-benzimidazol-1-yl)-3-phenyl-2-propen-1-one, and oxidation with hydrogen peroxide gives benzimidazole-2-sulfonic acid and 3-aryl-2-propenoic acids. 2005 Pleiades Publishing, Inc.
- Britsun,Esipenko,Chernega,Lozinskii
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- STEREOSPECIFIC NICKEL AND PHASE TRANSFER CATALYZED CARBONYLATION OF VINYL BROMIDES AND CHLORIDES
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Nickel cyanide catalyzes the carbonylation of vinyl bromides and chlorides to α,β-unsaturated acids.
- Alper, Howard,Amer, Ibrahim,Vasapollo, Giuseppe
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- Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres supported palladium complex as an efficient catalyst for Heck reaction
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Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres synthesized by suspension polymerization were used as supports for palladium catalyst. The results showed the novel magnetic catalyst can promote Heck reaction of aryl halides with acrylic acid efficiently without an inert atmosphere. In addition, the novel catalyst can be conveniently recovered by applying an external magnet and reused at least five times without significant loss of its activity.
- Yuan, Ding Zhong,Zhang, Qiu Yu,Dou, Jin Bo
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- Contributions of conserved serine and tyrosine residues to catalysis, ligand binding, and cofactor processing in the active site of tyrosine ammonia lyase
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Tyrosine ammonia lyase (TAL) catalyzes the conversion of l-tyrosine to p-coumaric acid using a 3,5-dihydro-5-methylidene-4H-imidazole-4-one (MIO) prosthetic group. In bacteria, TAL is used for production of the photoactive yellow protein chromophore and for caffeic acid biosynthesis in certain actinomycetes. Here we biochemically examine wild-type and mutant forms of TAL from Rhodobacter sphaeroides (RsTAL). Kinetic analysis of RsTAL shows that the enzyme displays a 90-fold preference for l-tyrosine versus l-phenylalanine as a substrate. The pH-dependence of TAL activity with l-tyrosine and l-phenylalanine demonstrates a common protonation state for catalysis, but indicates a difference in charge-state for binding of either amino acid. Site-directed mutagenesis demonstrates that Ser150, Tyr60, and Tyr300 are essential for catalysis. Mutation of Ser150 to an alanine abrogates formation of the MIO prosthetic group, as shown by mass spectrometry, and prevents catalysis. The Y60F and Y300F mutants were inactive with both amino acid substrates, but bound p-coumaric and cinnamic acids with less than 12-fold changes in affinity compared the wild-type enzyme. Analysis of MIO-dithiothreitol adduct formation shows that the reactivity of the prosthetic group is not significantly altered by mutation of either Tyr60 or Tyr300. The mechanistic roles of Ser150, Tyr60, and Tyr300 are discussed in relation to the three-dimensional structure of RsTAL and related MIO-containing enzymes.
- Schroeder, Amy C.,Kumaran, Sangaralingam,Hicks, Leslie M.,Cahoon, Rebecca E.,Halls, Coralie,Yu, Oliver,Jez, Joseph M.
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- A new phenolic glycoside from the stem of Dendrobium nobile
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A new phenolic glycoside dendroside (1), together with seven known compounds (2–8) were isolated from the stems of Dendrobium nobile. The structures of these compounds were elucidated using comprehensive spectroscopic methods. The inhibitory activities of all compounds against three cancer cell lines HeLa, MCF-7 and A549 were evaluated.
- Zhou, Xue-Ming,Zheng, Cai-Juan,Wu, Jia-Ting,Chen, Guang-Ying,Zhang, Bin,Sun, Chong-Ge
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- Batatins VIII-XI, glycolipid ester-type dimers from ipomoea batatas
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Sweet potato (Ipomoea batatas) is native to the tropics of Central and South America, where many varieties have been consumed for more that 5000 years. In developing countries, this crop is a recognized effective food for fighting malnutrition. Purification of the minor lipophilic glicolipids found in the n-hexane-soluble resin glycosides from the white-skinned variety was performed by preparative-scale recycling HPLC. Application of column overload, peak shaving, heart cutting, and recycling techniques permitted the purification of four new oligosaccharide ester-type dimer derivatives of jalapinolic acid, batatins VIII-XI (1-4). The structural characterization of these complex lipo-oligosaccharides was performed through NMR spectroscopy and MS, indicating that batatins VIII-XI (1-4) possess an oligomeric structure consisting of two pentasaccharide units of the known simonic acid B.
- Rosas-Ramírez, Daniel,Pereda-Miranda, Rogelio
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- NHC-Ag/Pd-Catalyzed Reductive Carboxylation of Terminal Alkynes with CO2 and H2: A Combined Experimental and Computational Study for Fine-Tuned Selectivity
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Reductive carboxylation of terminal alkynes utilizing CO2 and H2 as reactants is an interesting and challenging transformation. Theoretical calculations indicated it would be kinetically possible to obtain cinnamic acid, the reductive carboxylation product, from phenylacetylene in a CO2/H2 system with an N-heterocyclic carbene (NHC)-supported Ag/Pd bimetallic catalysts through competitive carboxylation/hydrogenation cascade reactions in one step. These calculations were verified experimentally with a poly-NHC-supported Ag/Pd catalyst. By tuning the catalyst composition and reaction temperature, phenylacetylene was selectively converted to cinnamic acid, hydrocinnamic acid, or phenylpropiolic acid in excellent yields.
- Yu, Dingyi,Zhou, Feng,Lim, Diane S. W.,Su, Haibin,Zhang, Yugen
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- Not quite the last word on the Perkin reaction
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Microwave irradiation does not accelerate the rate of the Perkin reaction carried out under normal atmospheric pressure. Water is an essential yet catalytic reactant for the Perkin reaction to occur. Containment of the Perkin reaction in a sealed vessel improves the yield. Two pressure increases are observed during a 4 h reaction time. An induction period is seen in the Perkin reaction when sodium acetate is used as a base. A re-appraisal of the reaction mechanism is proposed on the basis of these observations. The use of PFA reaction vessels enables the Perkin reaction to occur under aqueous conditions for around 80 reactions/vessel.
- Edwards, Mark,Rourk, Paul M.,Riby, Philip G.,Mendham, Andrew P.
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- Investigating the roles of T224 and T232 in the oxidation of cinnamaldehyde catalyzed by myxobacterial CYP260B1
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Although the oxidation of aldehydes to carboxylic acids is mainly catalyzed by aldehyde dehydrogenases in nature, cytochromes P450 are also able to perform such reactions. In this study, we demonstrate the oxidation of cinnamaldehyde to cinnamic acid by the myxobacterial CYP260B1. Following our docking studies of the aldehyde, we generated T224A and T234A mutants of CYP260B1 by site-directed mutagenesis to disrupt the substrate positioning and proton delivery, respectively. Furthermore, we used the kinetic solvent isotope effect on the steady-state turnover of the substrate to investigate the reactive intermediate capable of performing the catalysis. Our results suggest that the aldehyde oxidation occurs via a nucleophilic attack of the ferric peroxoanion.
- Litzenburger, Martin,Lo Izzo, Roberta,Bernhardt, Rita,Khatri, Yogan
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- Application of the SPE Method to Organic Electrochemistry. XII. Lead Dioxide as a Mediator for Electrooxidation of Cinnamyl Alcohol on Pt-Nafion
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Lead dioxide was examined as a mediator to oxidize cinnamyl alcohol on Pt-Nafion, and was compared with manganese dioxide.Lead dioxide was deposited into Pt-Nafion.The current efficiency for the formation of cinnamaldehyde reached 65percent at room temperature, slightly lower than that in the case of using manganese dioxide.The production of cinnamic acid was more remarkable on Pb,Pt-Nafion than on Mn,Pt-Nafion because of the higher oxidation potential of the former.The mediatory action of both oxides was examined and compared with the activity in chemical oxidation using oxides produced separately.The oxidation of cinnamyl alcohol by lead dioxide was faster than that by the manganese dioxide.Their mediatory action reflected their chemical activity for the oxidation.
- Chen, Zhen,Ogumi, Zempachi,Takehara, Zen-ichiro
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- Synthesis of O,N,O[sbnd]P multidentate ligands and the formation of early–late heterobimetallic complexes
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A multidentate O,N,O[sbnd]P ligand 4 designed for early–late heterobimetallic (ELHB) complexes was synthesized. The ligand 4 has an O,N,O-tridentate ligand moiety and a triarylphosphine group. The O,N,O-moiety based on lutidine scaffold selectively coordinated to early transition metals such as titanium and niobium in the reaction with the corresponding metal alkoxides to form mononuclear complexes. Coordination of the triarylphosphine moiety to the niobium atom was negligible in the Nb-ONO[sbnd]P complex according to 31P NMR spectroscopy, whereas a part of the phosphorus atom coordinated to the titanium atom in the Ti-ONO[sbnd]P complex. Addition of [PdCl(π-allyl)]2 or [RhCl(cod)]2 to the Nb-ONO[sbnd]P complex gave rise to the formation of ELHB complexes. Thus, the one-pot preparation of ELHB complexes was achieved by simple procedure.
- Suzuki, Noriyuki,Yoneyama, Satoru,Shiba, Keisuke,Hasegawa, Takeshi,Masuyama, Yoshiro
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- Homogeneous chromium(VI)-catalyzed oxidations of allylic alcohols by alkyl hydroperoxides: Influence of the nature of the alkyl group on the product distribution
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The chromium oxide-catalyzed oxidation of allylic alcohols - R1CH(OH)CR2=CHR3 - by ROOH (R= t-Bu, PhCMe2) affords generally a mixture of R1COCR2=CHR3 and R1CH=CR2COR3. The rate of the reaction and the ratio between the two oxidized compounds both depend on the nature of R. It has been concluded that the oxidative species and the reactive intermediates contain this R group.
- Riahi, Abdelkhalek,Henin, Francoise,Muzart, Jacques
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- Solvent-free bentonite-catalyzed condensation of malonic acid and aromatic aldehydes under microwave irradiation
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Solvent-free condensation between malonic acid and aromatic aldehydes in the presence of bentonite was investigated. Various diacids were obtained in good to moderate yields and in very short short reaction times under microwave irradiation. The method showed simplicity in performance, non-aqueous work-up, no side products and low cost.
- Loupy, Andre,Song, Suk-Jin,Sohn, Sun-Mee,Lee, Young-Mee,Kwon, Tae-Woo
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- Two acylated flavone glucosides from Andrographis serpyllifolia
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Two new acylated flavone glucosides, skullcapflavone I 2'-O-β-D-(3-E- cinnamoyl)glucopyranoside and skullcapflavone I 2'-Oβ-D-(2-E- cinnamoyl)glucopyranoside, together with skullcapflavone I 2'-O-β-D- glucopyranoside and andrographidine C have been isolated from the whole plant of Andrographis serpyllifolia. Structural elucidation of the glycosides was achieved by various NMR techniques including 1H-1H COSY, HMQC, HMBC and ROESY experiments, FAB-mass spectrometry, acid hydrolysis and saponification.
- Damu,Jayaprakasam,Gunasekar,Blond,Bodo
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- Kinetic analysis of the inhibition of phenylalanine ammonia-lyase by 2-aminoindan-2-phosphonic acid and other phenylalanine analogues
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The conformationally restricted phenylalanine analogue 2-aminoindan-2-phosphonic acid (AIP) inhibits phenylalanine ammonialyase (PAL) competitively in a time-dependent manner. This phenomenon was investigated in more detail with the heterologously expressed, highly purified homotetrameric PAL-1 isozyme from parsley. The kinetic analysis revealed that the enzyme-inhibitor complex is formed in a single "slow" step with an association rate of k2 = 2.6±0.04 104 M-1 s-1. The inhibition is reversible with a dissociation rate of k-2 = 1.8±0.04 10-4 s-1 and an equilibrium constant of Ki = 7±2 nM. The previously described PAL inhibitor (S)-2-aminooxy-3-phenylpropanoic acid [(S)-AOPP] was also found to be a slow-binding inhibitor of PAL-1. The carboxyl analogue of AIP, 2-aminoindan-2-carboxylic acid, served as a substrate of PAL-1 and was converted to indene-2-carboxylic acid.
- Appert, Christoph,Zon, Jerzy,Amrhein, Nikolaus
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- ADSORPTION AND REACTION OF TRANS-CINNAMONITRILE ON A SILVER SURFACE INVESTIGATED BY RAMAN SPECTROSCOPY
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Adsorption of trans-cinnamonitrile on the metal surface in silver sol has been investigated by the surface-enhanced Raman scattering technique.The molecule is found to adsorb on the surface via its nitrogen lone pair electrons.In the absence of coadsorbed chloride ions, the molecule is converted to trans-cinnamic acid by a surface reaction.When a small amount of sample is irradiated with a laser, a surface photoreaction of trans-cinnamonitrile is observed.
- Chun, Hyun Aee,Kim, Myung Soo,Kim, Kwan
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- RUTHENATE ION CATALYSED OXIDATION OF SOME UNSATURATED ALCOHOLS BY ALKALINE HEXACYANOFERRATE(III) ION
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The kinetics of ruthenate ion catalysed oxidation of allyl alcohol, crotyl alcohol, cinnamyl alcohol and propargyl alcohol by hexacyanoferrate(III) ion in aqueous alkaline media at constant ionic strength indicate no dependence of rate on alkali concentration or ionic strength.The reaction shows first order dependence on ruthenate ion and zero order in hexacyanoferrate(III) ion.The rate of the reaction increases with increase in substrate concentration and shows Michaelis-Menten type of behaviour.The data suggests that the oxidation proceeds via the formation of a complex between an alcohol molecule and ruthenate ion yielding corresponding acids.The reaction has been studied at four different temperatures and thermodynamic parameters have been computed.A plausible mechanism consistent with the experimental results is proposed.
- Dwivedi, R. K.,Verma, Meena,Kumar, Pradeep,Behari, K.
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- New Flavonoids and Turkesterone-2-O-Cinnamate from Leaves of Rhaponticum uniflorum
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Leaves of Rhaponticum uniflorum (L.) DC. (Asteraceae) afforded 46 compounds including seven new flavonoids that were identified using UV, IR, and NMR spectroscopy and mass spectrometry as 6-hydroxyluteolin-7-O-(2′-O-caffeoyl)-β-D-glucopyranoside (rhaunoside A, 1), 6-hydroxyluteolin-7-O-(6″-O-cinnamoyl)-β-D-glucopyranoside (rhaunoside B, 2), 6-hydroxyluteolin-4′-O-β-D-glucopyranoside (rhaunoside C, 3), nepetin-7-O-(6″-O-caffeoyl)-β-D-glucopyranoside (rhaunoside D, 4), nepetin-7-O-(6″-O-cinnamoyl)-β-D-glucopyranoside (rhaunoside E, 5), nepetin-3′-O-β-D-glucopyranoside (rhaunoside F, 6), and luteolin-7-O-(2″-O-caffeoyl)-β-D-glucopyranoside (rhaunoside G, 7) and the new ecdysteroid turkesterone-2-O-cinnamate (8).
- Olennikov,Kashchenko
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- Pd(II)-Catalyzed CC Bond Cleavage by a Formal Group-Exchange Reaction
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A chelation-assisted palladium-catalyzed CC bond cleavage of α, β-unsaturated ketone to form alkenyl nitrile in the presence of nitrile is disclosed on the basis of a formal group-exchange reaction formulated as C1C2 + C3 → C1C3 + C2, differing from normal alkene oxidative cleavage and metathesis type. The isolated key active Pd(II) complex as well as deuterium-labeled experiment revealed the necessity of the chelation group, and a plausible catalytic pathway was proposed.
- Ye, Runyou,Zhu, Maoshuai,Yan, Xufei,Long, Yang,Xia, Ying,Zhou, Xiangge
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p. 8678 - 8683
(2021/07/26)
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- Larvicidal activity and in silico studies of cinnamic acid derivatives against Aedes aegypti (Diptera: Culicidae)
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Cinnamic acid derivatives (CAD's) represent a great alternative in the search for insecticides against Aedes aegypti mosquitoes since they have antimicrobial and insecticide properties. Ae. aegypti is responsible for transmitting Dengue, Chikungunya, and Zika viruses, among other arboviruses associated with morbimortality, especially in developing countries. In view of this, in vitro analyses of n-substituted cinnamic acids and esters were performed upon 4th instar larvae (L4) of Ae. aegypti, as well as, molecular docking studies to propose a potential biological target towards this mosquitoes species. The larvicide assays proved that n-substituted ethyl cinnamates showed a more pronounced activity than their corresponding acids, in which p-chlorocinnamate (3j) presented a LC50 value of 8.3 μg/mL. Thusly, external morphologic alterations (rigid and elongated body, curved bowel, and translucent or darkened anal papillae) of mosquitoes’ group exposed to compound 3j, were observed by microscopy. In addition, an analytical method was developed for the quantification of the most promising analog by using high-performance liquid chromatography with UV detection (HPLC-UV). Molecular docking studies suggested that the larvicide action is associated with inhibition of acetylcholinesterase (AChE) enzyme. Therefore, expanding the larvicidal study with the cinnamic acid derivatives against the vector Ae. aegypti is important for finding search for more effective larvicides and with lower toxicity, since they have already shown good larvicidal properties against Ae. aegypti.
- Bezerra Fran?a, Saraliny,Carine Barros de Lima, Luana,Rychard da Silva Cunha, Cristhyan,Santos Anuncia??o, Daniela,Ferreira da Silva-Júnior, Edeildo,Ester de Sá Barreto Barros, Maria,José da Paz Lima, Dimas
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- Synthesis, spectroscopic characterization and DNA/HSA binding studies of (phenyl/naphthyl)ethenyl-substituted 1,3,4-oxadiazolyl-1,2,4-oxadiazoles
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Two new series of conjugated arylethenyl-1,3,4-oxadiazolyl-1,2,4-oxadiazoles were obtained and spectroscopically characterized in terms of UV-Vis absorption, fluorescence and interaction with CT-DNA and Human Serum Albumin (HSA) biomolecules. Phenyl- and 1-naphthyl-bearing examples were analysed, and the spectroscopic properties of its substitution series were compared, showing extensive conjugation in all compounds and absorption differences due to both the aryl-ethenyl subunit and substituted phenyl/phenylene at the 1,2,4-oxadiazole side. Strong binding interactions of the obtained compounds with CT-DNA and moderate HSA-association capability were observed spectroscopically, and further docking studies were performed. This journal is
- Mayer, Joao C. P.,Acunha, Thiago V.,Rodrigues, Oscar E. D.,Back, Davi F.,Chaves, Otavio A.,Dornelles, Luciano,Iglesias, Bernardo A.
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p. 471 - 484
(2021/01/11)
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- Photocatalytic Oxidative [2+2] Cycloelimination Reactions with Flavinium Salts: Mechanistic Study and Influence of the Catalyst Structure
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Flavinium salts are frequently used in organocatalysis but their application in photoredox catalysis has not been systematically investigated to date. We synthesized a series of 5-ethyl-1,3-dimethylalloxazinium salts with different substituents in the positions 7 and 8 and investigated their application in light-dependent oxidative cycloelimination of cyclobutanes. Detailed mechanistic investigations with a coumarin dimer as a model substrate reveal that the reaction preferentially occurs via the triplet-born radical pair after electron transfer from the substrate to the triplet state of an alloxazinium salt. The very photostable 7,8-dimethoxy derivative is a superior catalyst with a sufficiently high oxidation power (E=2.26 V) allowing the conversion of various cyclobutanes (with Eox up to 2.05 V) in high yields. Even compounds such as all-trans dimethyl 3,4-bis(4-methoxyphenyl)cyclobutane-1,2-dicarboxylate can be converted, whose opening requires a high activation energy due to a missing pre-activation caused by bulky adjacent substituents in cis-position.
- Hartman, Tomá?,Reisnerová, Martina,Chudoba, Josef,Svobodová, Eva,Archipowa, Nataliya,Kutta, Roger Jan,Cibulka, Radek
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p. 373 - 386
(2021/02/01)
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- Iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabled aldehyde C-H methylation
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A practical and general iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabling aldehyde C-H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses ambient air as the sole oxidant and tolerates sensitive functional groups for the late-stage functionalization of complex natural-product-derived and polyfunctionalized molecules.
- Gong, Pei-Xue,Xu, Fangning,Cheng, Lu,Gong, Xu,Zhang, Jie,Gu, Wei-Jin,Han, Wei
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supporting information
p. 5905 - 5908
(2021/06/18)
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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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- Design, Synthesis, and Anticancer Activity of Cinnamoylated Barbituric Acid Derivatives
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This work deals with the design and synthesis of 18 barbituric acid derivatives bearing 1,3-dimethylbarbituric acid and cinnamic acid scaffolds to find potent anticancer agents. The target molecules were obtained through Knoevenagel condensation and acylation reaction. The cytotoxicity was assessed by the MTT assay. Flowcytometry was performed to determine the cell cycle arrest, apoptosis, ROS levels and the loss of MMP. The ratios of GSH/GSSG and the MDA levels were determined by using UV spectrophotometry. The results revealed that introducing substitutions (CF3, OCF3, F) on the meta- of the benzyl ring of barbituric acid derivatives led to a considerable increase in the antiproliferative activities compared with that of corresponding ortho- and para-substituted barbituric acid derivatives. Mechanism investigation implied that the 1c could increase the ROS and MDA level, decrease the ratio of GSH/GSSG and MMP, and lead to cell cycle arrest. Further research is needed for structural optimization to enhance hydrophilicity, thereby improve the biological activity of these compounds.
- Li, Peng-Xiao,Liu, Guo-Yun,Liu, Ren-Min,Liu, Yue,Mu, Wen-Wen,Sun, Ya-Lei,Yang, Jie
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- Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
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The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
- Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
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p. 167 - 175
(2021/03/19)
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- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
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The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
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supporting information
p. 6648 - 6653
(2021/09/08)
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- (Hexamethylbenzene)Ru catalysts for the Aldehyde-Water Shift reaction
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The Aldehyde-Water Shift (AWS) reaction uses H2O as a benign oxidant to convert aldehydes to carboxylic acids, producing H2, a valuable reagent and fuel, as its sole byproduct. (Hexamethylbenzene)RuIIcomplexes are demonstrated to have higher activity and selectivity (up to 95%) for AWS over disproportionation than previously reported catalysts.
- Phearman, Alexander S.,Moore, Jewelianna M.,Bhagwandin, Dayanni D.,Goldberg, Jonathan M.,Heinekey, D. Michael,Goldberg, Karen I.
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supporting information
p. 1609 - 1615
(2021/03/09)
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- Pt-Catalyzed selective oxidation of alcohols to aldehydes with hydrogen peroxide using continuous flow reactors
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The oxidation of alcohols to aldehydes is a powerful reaction pathway for obtaining valuable fine chemicals used in pharmaceuticals and biologically active compounds. Although many oxidants can oxidize alcohols, only a few hydrogen peroxide oxidations can be employed to continuously synthesize aldehydes in high yields using a liquid-liquid two-phase flow reactor, despite the possibility of the application toward a safe and rapid multi-step synthesis. We herein report the continuous flow synthesis of (E)-cinnamaldehyde from (E)-cinnamyl alcohol in 95%-98% yields with 99% selectivity for over 5 days by the selective oxidation of hydrogen peroxide using a catalyst column in which Pt is dispersed in SiO2. The active species for the developed selective oxidation is found to be zero-valent Pt(0) from the X-ray photoelectron spectroscopy measurements of the Pt surface before and after the oxidation. Using Pt black diluted with SiO2as a catalyst to retain the Pt(0) species with the optimal substrate and H2O2introduction rate not only enhances the catalytic activity but also maintains the activity during the flow reaction. Optimizing the contact time of the substrate with Pt and H2O2using a flow reactor is important to proceed with the selective oxidation to prevent the catalytic H2O2decomposition.
- Kon, Yoshihiro,Nakashima, Takuya,Yada, Akira,Fujitani, Tadahiro,Onozawa, Shun-Ya,Kobayashi, Shū,Sato, Kazuhiko
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supporting information
p. 1115 - 1121
(2021/02/16)
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- Dual Nickel/Ruthenium Strategy for Photoinduced Decarboxylative Cross-Coupling of α,β-Unsaturated Carboxylic Acids with Cycloketone Oxime Esters
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Herein, a dual nickel/ruthenium strategy is developed for photoinduced decarboxylative cross-coupling between α,β-unsaturated carboxylic acids and cycloketone oxime esters. The reaction mechanism is distinct from previous photoinduced decarboxylation of α,β-unsaturated carboxylic acids. This reaction might proceed through a nickelacyclopropane intermediate. The C(sp2)-C(sp3) bond constructed by the aforementioned reaction provides an efficient approach to obtaining various cyanoalkyl alkenes, which are synthetically valuable organic skeletons in organic and medicinal chemistry, under mild reaction conditions. The protocol tolerates many critical functional groups and provides a route for the modification of complex organic molecules.
- Gao, Ang,Jiang, Run-Chuang,Liu, Chuang-Chuang,Liu, Qi-Le,Lu, Xiao-Yu,Xia, Ze-Jie
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p. 8829 - 8842
(2021/06/30)
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- A novel phenylalanine ammonia-lyase from Pseudozyma antarctica for stereoselective biotransformations of unnatural amino acids
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A novel phenylalanine ammonia-lyase of the psychrophilic yeast Pseudozyma antarctica (PzaPAL) was identified by screening microbial genomes against known PAL sequences. PzaPAL has a significantly different substrate binding pocket with an extended loop (26 aa long) connected to the aromatic ring binding region of the active site as compared to the known PALs from eukaryotes. The general properties of recombinant PzaPAL expressed in E. coli were characterized including kinetic features of this novel PAL with L-phenylalanine (S)-1a and further racemic substituted phenylalanines rac-1b-g,k. In most cases, PzaPAL revealed significantly higher turnover numbers than the PAL from Petroselinum crispum (PcPAL). Finally, the biocatalytic performance of PzaPAL and PcPAL was compared in the kinetic resolutions of racemic phenylalanine derivatives (rac-1a-s) by enzymatic ammonia elimination and also in the enantiotope selective ammonia addition reactions to cinnamic acid derivatives (2a-s). The enantiotope selectivity of PzaPAL with o-, m-, p-fluoro-, o-, p-chloro- and o-, m-bromo-substituted cinnamic acids proved to be higher than that of PcPAL.
- Varga, Andrea,Csuka, Pál,Sonesouphap, Orlavanah,Bánóczi, Gergely,To?a, Monica Ioana,Katona, Gabriel,Molnár, Zsófia,Bencze, László Csaba,Poppe, László,Paizs, Csaba
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p. 185 - 194
(2020/04/28)
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- An Ir3L2complex with anion binding pockets: photocatalyticE-Zisomerizationviamolecular recognition
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A molecular host with photosensitizing centers provides photo-responsive host-guest properties based on its molecular recognition ability. Here, we construct a self-assembled photoactive Ir(iii) cage-shaped complex that contains anion binding pockets on its rim. The anion recognition ability of the complex enables efficient catalysis of the visible-light-inducedE-Zisomerization of an anionic styrene derivative.
- Fujita, Makoto,Koyamada, Kenta,Sunohara, Haruka,Takezawa, Hiroki
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supporting information
p. 9300 - 9302
(2021/09/20)
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- Water-initiated hydrocarboxylation of terminal alkynes with CO2and hydrosilane
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This work discloses a Cu(ii)-Ni(ii) catalyzed tandem hydrocarboxylation of alkynes with polysilylformate formed from CO2and polymethylhydrosiloxane that affords α,β-unsaturated carboxylic acids with up to 93% yield. Mechanistic studies indicate that polysilylformate functions as a source of CO and polysilanol. Besides, a catalytic amount of water is found to be critical to the reaction, which hydrolyzes polysilylformate to formic acid that induces the formation of Ni-H active species, thereby initiating the catalytic cycle.
- Wang, Meng-Meng,Lu, Sheng-Mei,Paridala, Kumaraswamy,Li, Can
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supporting information
p. 1230 - 1233
(2021/02/09)
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- Method for preparing alpha, beta-unsaturated carboxylic acid compound
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The invention discloses a method for preparing an alpha, beta-unsaturated carboxylic acid compound, which comprises the following steps: 1) in an atmosphere containing carbon dioxide, heating and reacting a mixture containing hydrosilane and a copper catalyst to obtain a system I; and 2) adding a raw material containing alkyne and a nickel catalyst into the system I in the step 1), and heating to react. The method has the advantages of simple, easily available, cheap and stable raw materials, common, easily available and stable catalyst, mild reaction conditions, simple post-treatment, high yield and the like.
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Paragraph 0103-0406
(2021/05/05)
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- Biocatalytic Oxidation of Sulfides to Sulfones
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This paper describes a method for the biocatalytic oxidation of sulfides. During the screening of microorganisms using pure cultures of bacteria and fungi for the oxidation of sulfides, it was observed that a number of strains of microorganisms, were able to oxidize various sulfides (1-4), but the desired sulfoxide was either not obtained or obtained only as a minor product. A close observation of the reaction showed complete oxidation and thus sulfone (5-8) formation had occurred in these cases. Sulfones are used to stabilize intermediates like α-radicals, α-anions etc. and also used as cationic synthons in many known reactions. This prompted us to explore the sulfone synthesis by biocatalytic route. Approximately 20% of the strains tested (400 bacterial and 200 fungal) showed the formation of sulfone with conversion rate varying from 3 to 100% based on TLC analysis. There were two strains of fungi, Aspergillus ochraceus MTCC 5245 and Penicillium Funiculosum MTCC 5246 which showed excellent biocatalytic activity for oxidation sulfides to corresponding sulfones in high yield. In all these strains, the product was different from corresponding standard sulfoxide prepared by oxidation with m-chloroperbenzoic acid but well corresponded with the standard sample of sulfone prepared by oxidation of the corresponding sulfides with oxone. The identity of sulfones in all cases was confirmed by 1H NMR. Published by Oriental Scientific Publishing Company
- Dhiman, Shefali
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p. 250 - 255
(2021/03/29)
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- BiCl3-Facilitated removal of methoxymethyl-ether/ester derivatives and DFT study of -O-C-O- bond cleavage
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A simple method for the cleavage of methoxymethyl (MOM)-ether and ester derivatives using bismuth trichloride (BiCl3) is described. The alkyl, alkenyl, alkynyl, benzyl and anthracene MOM ether derivatives, as well as MOM esters of both aliphatic and aromatic carboxylic acids, were deprotected in good yields. To better understand the molecular roles of BiCl3and water for MOM cleavage, two possible binding pathways were investigated using the density functional theory (DFT) method. The theoretical results indicate the differential initial binding site preferences of phenolic and alcoholic MOM substrates to the Bi atom and suggest that water plays a key role in facilitating the cleavage of the MOM group.
- Pacherille, Angela,Tuga, Beza,Hallooman, Dhanashree,Dos Reis, Isaac,Vermette, Mélodie,Issack, Bilkiss B.,Rhyman, Lydia,Ramasami, Ponnadurai,Sunasee, Rajesh
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supporting information
p. 7109 - 7116
(2021/05/03)
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- Intermediate substance with acid degradation function, preparation method of same, and polymerizable monomer prepared from intermediate substance
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The invention discloses an intermediate substance with an acid degradation function and a preparation method of same; whereinthe preparation method of the intermediate substance comprises the following steps: dissolving 2-nitrobenzaldehyde in a proper amount of dichloromethane, if the reaction substance is cinnamyl aldehyde, mixing the substance with trimethyl orthoformate without the help of a dichloromethane solvent with hafnium trifluoromethanesulfonate as a catalyst; then under the condition of room temperature, performing magnetic stirring to obtain the target substance in a very short time. According to the invention, the defects of time consumption, energy consumption, solvent consumption and the like caused by adopting p-toluenesulfonic acid as a catalyst for preparing the substance traditionally are avoided, and the prepared substance has an acid degradation function. Corresponding 2-nitrobenzaldehyde or cinnamyl aldehyde can be obtained through acid degradation, and in addition, the intermediate substance provides convenience for subsequent preparation of polymerizable monomers with an acid degradation function.
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Paragraph 0054; 0057; 0059-0060; 0073
(2021/11/27)
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- Stereodivergent silver-catalyzed synthesis of pyroglutamic acid esters
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We report here a silver-catalyzed method for the enantio- and diastereodivergent synthesis of chiral pyroglutamic acid esters with multiple stereocenters. This process proceeds through asymmetric conjugate addition of glycine imine esters to a broad range of β-substituted α,β-unsaturated perfluorophenyl esters followed by lactamization. By leveraging catalyst control and stereospecificity of the 1,4-addition process, all four product stereoisomers containing two adjacent stereocenters are accessible with high stereoselectivity.
- Kim, Byungjun,Lee, Sarah Yunmi,Song, Yuna
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supporting information
p. 11052 - 11055
(2021/10/30)
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- Activated charcoal as an effective additive for alkaline and acidic hydrolysis of esters in water
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Activated charcoal largely enhanced the rates of the alkaline hydrolysis of methyl, ethyl, and n-propyl esters in aqueous 1.5 M NaOH solution to give the corresponding carboxylic acids in excellent yields. The acidic hydrolysis of methyl, ethyl, and n-propyl esters in aqueous 3 M H2SO4 solution was accelerated by the addition of activated charcoal to afford the corresponding carboxylic acids in good yields.
- Rohand, Taoufik,Tanemura, Kiyoshi
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supporting information
(2020/10/08)
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- Transfer semihydrogenation of alkynes catalyzed by imidazo[1,5-a]pyrid-3-ylidenepd complexes: Positive effects of electronic and steric features on N-heterocyclic carbene ligands
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To investigate the catalytic utility of the imidazo[1,5-a]pyrid-3-ylidene (IPC) ligand, Pd-catalyzed transfer semihydrogenation of alkynes with formic acid as a hydrogen source was conducted. The steric bulkiness of the substituent on N2 affected the configuration of the π-allyl moiety of the precatalyst of IPC-Pd-π-allyl complexes and the robustness of the catalytic process. The catalytic activities of IPC-Pd complexes were clearly higher than those of conventional NHC-Pd complexes.
- Mizuno, Takahiro,Murai, Toshiaki,Shibahara, Fumitoshi,Shibata, Yoshifuru
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p. 332 - 337
(2020/04/27)
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- Hydrogenation reaction method
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The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0265-0268
(2020/05/14)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- C–C Cross-Coupling Reactions of Organosilanes with Terminal Alkenes and Allylic Acetates Using PdII Catalyst Supported on Starch Coated Magnetic Nanoparticles
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Starch coated magnetic nanoparticles supported palladium catalyst has been explored to perform C–C cross coupling reactions, such as oxidative Heck coupling and Tsuji–Trost allylic coupling using organosilicon compounds as one of the coupling partners. The biopolymer coated magnetic catalyst was very easy to recover magnetically and was efficiently recycled in the subsequent batches. All the reactions were performed in air and thus the necessity of air and moisture free reaction condition is avoided. The present protocols show wide substrate scope and good yields of the products.
- Patra, Debabrata,Panja, Subir,Saha, Amit
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supporting information
p. 878 - 883
(2020/02/13)
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- Targeting inflammation with conjugated cinnamic amides, ethers and esters
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Background: Cinnamic acid is a key intermediate in shikimate and phenylpropanoid pathways. It is found both in free form, and especially in the form of esters in various essential oils, resins and balsams which are very important intermediates in the biosynthetic pathway of several natural products. The cinnamic derivatives play a vital role in the formation of commercially important intermediate molecules which are necessary for the production of different bioactive compounds and drugs. Different substitutions on basic moiety lead to various biological activities. Furthermore, combination of appropriate pharmacophore groups with cinnamic acid derivatives were developed to give hybrids in order to find out promising drug candidates as inhibitors of multiple biological targets associated with inflammation. We found interesting to continue our efforts to design and synthesise three series of novel cinnamic acid-based hybrids: a) nitrooxy esters of cinnamic acid, b) ethers and c) amides of cinnamic acids with arginine, as pleiotropic candidates against multiple targets of inflammation Methods: The synthesis of cinnamic was established by a Knoevenagel-Doebner condensation of the suitable aldehyde either with malonic acid in the presence of pyridine and piperidine, or with phenylacetic acid in the precence of triethylamine in acetic anhydride. The synthesis of the corresponding esters was conducted in two steps. The ethers were synthesized in low yields, with 1,2 – dibromoethane in dry acetone, in the presence of K2CO3, to give oily products. The corresponding cinnamic amides were synthesised in a single step. The synthesised hybrids were tested as lipoxygenase (LOX) and cyclooxygenase (COX) inhibitors in vitro. In silico docking was applied to all the novel derivatives. Several molecular properties of the hybrids were calculated in order to evaluate their drug likeness. Results: A number of esters, ethers and amides of selected cinnamic acids, either phenyl substituted or not, has been synthesised and subjected to modelling studies. The compounds were studied in vitro/in vivo for their inhibitory activities on cox and lox, and as antioxidants. Log P values of all the title compounds except of 3a (5.38) were found to be less than 5 and are in agreement to Lipinski’s rule of five, suggesting satisfactory permeability across cell membrane. The molecular modelling study seems to be in accordance with the experimental results for LOX and COX-2. The result of antioxidant activity for amide 3b supports the anti-lox activity. Compound 5d presents the higher in vivo anti-inflammatory. Conclusion: According to the experimental findings compounds 3b and 5d can be used as lead compounds for the design of new molecules to target inflammation.
- Fotopoulos, Ioannis,Litina, Dimitra Hadjipavlou,Pontiki, Eleni
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- Design, synthesis, and evaluation of novel cinnamic acid-tryptamine hybrid for inhibition of acetylcholinesterase and butyrylcholinesterase
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Background: Acetylcholine deficiencies in hippocampus and cortex, aggregation of β-amyloid, and β-secretase over activity have been introduced as main reasons in pathogenesis of Alzheimer’s disease. Methods: Colorimetric Ellman’s method was used for determination of IC50 value in AChE and BChE inhibitory activity. The kinetic studies, neuroprotective and β-secretase inhibitory activities, evaluation of inhibitory potency on β-amyloid (Aβ) aggregations induced by AChE, and docking study were performed for prediction of the mechanism of action. Result and discussion: A new series of cinnamic acids-tryptamine hybrid was designed, synthesized, and evaluated as dual cholinesterase inhibitors. These compounds demonstrated in-vitro inhibitory activities against acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE). Among of these synthesized compounds, (E)-N-(2-(1H-indol-3-yl)ethyl)-3-(3,4-dimethoxyphenyl)acrylamide (5q) demonstrated the most potent AChE inhibitory activity (IC50 = 11.51?μM) and (E)-N-(2-(1H-indol-3-yl)ethyl)-3-(2-chlorophenyl)acrylamide (5b) were the best anti-BChE (IC50 = 1.95?μM) compounds. In addition, the molecular modeling and kinetic studies depicted 5q and 5b were mixed type inhibitor and bound with both the peripheral anionic site (PAS) and catalytic sites (CAS) of AChE and BChE. Moreover, compound 5q showed mild neuroprotective in PC12 cell line and weak β-secretase inhibitory activities. This compound also inhibited aggregation of β-amyloid (Aβ) in self-induced peptide aggregation test at concentration of 10?μM. Conclusion: It is worth noting that both the kinetic study and the molecular modeling of 5q and 5b depicted that these compounds simultaneously interacted with both the catalytic active site and the peripheral anionic site of AChE and BChE. These findings match with those resulted data from the enzyme inhibition assay. [Figure not available: see fulltext.]
- Ghafary, Shahrzad,Ghobadian, Roshanak,Mahdavi, Mohammad,Nadri, Hamid,Moradi, Alireza,Akbarzadeh, Tahmineh,Najafi, Zahra,Sharifzadeh, Mohammad,Edraki, Najmeh,Moghadam, Farshad Homayouni,Amini, Mohsen
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p. 463 - 477
(2020/05/25)
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- Anticholinesterase activity of cinnamic acids derivatives: In vitro, in vivo biological evaluation, and docking study
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Background: Acetylcholine deficiency in the hippocampus and cortex, aggregation of amyloid-beta, and beta-secretase overactivity have been introduced as the main reasons in the formation of Alzheimer’s disease. Objective: A new series of cinnamic derived acids linked to 1-benzyl-1,2,3-triazole moiety were designed, synthesized, and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. Methods: Colorimetric Ellman’s method was used for the determination of IC50% of AchE and BuChE inhibitory activity. The kinetic studies, neuroprotective activity, BACE1 inhibitory activity, evaluation of inhibitory potency on Aβ1-42 self-aggregation induced by AchE, and docking study were performed for studying the mechanism of action. Results: Some of the synthesized compounds, compound 7b-4 ((E)-3-(3,4-dimethoxyphenyl)-N-((1(4-fluorobenzyl)-1H-1,2,3-triazole-4-yl) methyl) acrylamide) depicted the most potent acetylcholinesterase inhibitory activities (IC50 = 5.27 μM) and compound 7a-1 (N-((1-benzyl1H-1, 2, 3-triazole-4-yl) methyl) cinnamamide) demonstrated the most potent butyrylcholinesterase inhibitory activities (IC50 = 1.75 μM). Compound 7b-4 showed neuroprotective and β-secretase (BACE1) inhibitory activitiy. In vivo studies of compound 7b-4 in Scopolamine-induced dysfunction confirmed memory improvement. Conclusion: It should be noted that molecular modeling (compounds 7b-4 and 7a-1) and kinetic studies (compounds 7a-1 and 7b-4) showed that these synthesis compounds interacted simultaneously with both the catalytic site (CS) and peripheral anionic site (PAS) of AChE and BuChE.
- Akbarzadeh, Tahmineh,Amini, Mohsen,Edraki, Najmeh,Ghafary, Shahrzad,Mahdavi, Mohammad,Moghadam, Farshad Homayouni,Moradi, Alireza,Nadri, Hamid,Sharifzadeh, Mohammad
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p. 965 - 982
(2020/08/10)
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- The potential role of the 5,6-dihydropyridin-2(1: H)-one unit of piperlongumine on the anticancer activity
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Piperlongumine (PL), a potent anticancer agent from the plant long pepper (Piper longum), contains the 5,6-dihydropyridin-2(1H)-one heterocyclic scaffold and cinnamoyl unit. In this paper, we synthesized a series of PL analogs and evaluated their cytotoxicity against cancer cells for the sake of exploring which pharmacophore plays a more potent role in enhancing the anticancer activities of PL. These results illustrated that the position effect, not the electronic effect, of substituents plays a certain role in the cytotoxicity of PL and its analogs. More important, the 5,6-dihydropyridin-2(1H)-one unit, a potent pharmacophore in enhancing the antiproliferative activities of PL, could react with cysteamine and lead to ROS generation, and then bring about the occurrence of ROS-induced downstream events, followed by cell cycle arrest and apoptosis. This work suggests that introducing a lactam unit containing Michael acceptors may be a potent strategy to enhancing the anticancer activity of drugs. This journal is
- Li, Peng-Xiao,Liu, Guo-Yun,Liu, Yue,Mu, Wen-Wen,Yang, Jie
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p. 42128 - 42136
(2020/12/09)
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- Encapsulation of cinnamic acid by cucurbit[7]uril for enhancing photoisomerization
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Cis- or Z-configuration is required for the plant growth-promoting activity of cinnamic acid (CA), whereas the E-form is inactive. Herein, we describe the encapsulation of E-CA by cucurbit[7]uril (CB7) and show that photoisomerization reactions can be more efficiently controlled in aqueous solutions by utilizing this supramolecular approach. Measurements of UV-visible absorption and proton NMR spectra at different pH values confirm that E-CA and its methyl ester, methyl-E-cinnamate (MC), form stronger 1:1 host-guest complexes with CB7 compared to cucurbit[8]uril (CB8) or three cyclodextrins (α-, β-, and γ-CD). Irradiation of (300 nm) UV light to an aqueous solution of the CB7-bound E isomers induces E to Z photoisomerization and the dissociation of the complex. When the same solution is irradiated by (254 nm) UV light, Z to E conformational changes of the unbound Z isomers are observed and are accompanied by restoring the host-guest complex formation.
- Al-Ahdal, Asia,Al-Amodi, Hebah,Bojesomo, Rukayat,Bufaroosha, Muna S.,Moussa, Ziad,Saleh, Na'il
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- Cobalt-Catalyzed Acceptorless Dehydrogenation of Alcohols to Carboxylate Salts and Hydrogen
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The facile oxidation of alcohols to carboxylate salts and H2 is achieved using a simple and readily accessible cobalt pincer catalyst (NNNHtBuCoBr2). The reaction follows an acceptorless dehydrogenation pathway and displays good functional group tolerance. The amine-amide metal-ligand cooperation in cobalt catalyst is suggested to facilitate this transformation. The mechanistic studies indicate that in-situ-formed aldehydes react with a base through a Cannizzaro-type pathway, resulting in potassium hemiacetolate, which further undergoes catalytic dehydrogenation to provide the carboxylate salts and H2
- Gunanathan, Chidambaram,Kishore, Jugal,Pattanaik, Sandip,Pradhan, Deepak Ranjan
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supporting information
(2020/03/03)
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- Pd(OAc)2 promoted bis-N-heterocyclic carbene-catalyzed oxidative transformation of aldehydes
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The bis-N-heterocyclic carbene-catalyzed (bis-NHC-catalyzed) oxidative transformation of aldehydes was successfully studied in water under air. The reaction rate increased through the use of Pd(OAc)2 as an additive. Notably, the catalytic system exhibited good tolerance toward aliphatic and aromatic aldehydes bearing halide and alkyl functional groups. In addition, gram-scale reaction was also tested in this study. The use of water and operational simplicity make this methodology environmentally benign and cost-effective.
- Yu, Ya-Han,Wang, Tsui,Chiu, Chien-Cheng,Lu, Ta-Jung,Lee, Dong-Sheng
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p. 202 - 205
(2019/11/28)
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- Oxidation of aromatic and aliphatic aldehydes to carboxylic acids by Geotrichum candidum aldehyde dehydrogenase
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Oxidation reaction is one of the most important and indispensable organic reactions, so that green and sustainable catalysts for oxidation are necessary to be developed. Herein, biocatalytic oxidation of aldehydes was investigated, resulted in the synthesis of both aromatic and aliphatic carboxylic acids using a Geotrichum candidum aldehyde dehydrogenase (GcALDH). Moreover, selective oxidation of dialdehydes to aldehydic acids by GcALDH was also successful.
- Hoshino, Tomoyasu,Yamabe, Emi,Hawari, Muhammad Arisyi,Tamura, Mayumi,Kanamaru, Shuji,Yoshida, Keisuke,Koesoema, Afifa Ayu,Matsuda, Tomoko
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- Method for preparing carboxylic acid by catalyzing aldehyde oxidation with N-heterocyclic carbene
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The invention discloses a method for preparing carboxylic acid by catalyzing aldehyde oxidation with N-heterocyclic carbene, and relates to the field of catalytic technology. The method comprises thefollowing steps: taking deionized water as a solvent and aldehyde as a reaction substrate, adding alkali into a reaction system, taking air as an oxidant and N-heterocyclic carbene as a catalyst required by the reaction, and carrying out catalytic oxidation on aldehyde at room temperature to 80 DEG C to generate a corresponding reaction product. The method has the beneficial effects that the N-heterocyclic carbene is used as the catalyst, no organic solvent is needed in the reaction process, the reaction process is green and safe, and the reaction yield is high.
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Paragraph 0043; 0110-0112; 0113-0116; 0117-0120; 0121-0123
(2020/11/25)
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- Polymer hydrogel confined palladium nanoparticles as recyclable catalysts for Suzuki and Heck cross-coupling reactions
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Reusable palladium nanoparticles highly dispersed in porous and hydrophilic interpenetrating polymer networks (IPN), i.e., Pd@IPN hybrid gels, are employed for catalysis of Suzuki and Heck coupling reactions. Good yields are obtained with high turnover frequencies when the reactions are run with very low Pd-loadings. The use of IPN gives better recyclability than that of crosslinked polyvinyl alcohol alone. The polymer networks allow the reactants to have easy access to the Pd metals. The catalysts combine high activity with the reusability offered by the heterogeneous system, without the need for strong coordination or chelating ligands.
- Zhan, Kan,Lu, Ping,Dong, Jian,Hou, Xu
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supporting information
p. 1630 - 1634
(2020/07/30)
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- Amidoxime modified PAN supported palladium complex: A greener and efficient heterogeneous catalyst for heck reaction
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Development of a facile and greener approach for Heck reaction using a modified PAN supported palladium catalyst is described. The preparation of the catalyst involves a simple process through amidoxime modification of nitrile group in Polyacrylonitrile (PAN), followed by the complexation with Palladium chloride (PdCl2). The resulting supported catalyst was characterized by spectroscopic analyses and further by computational studies. This polymer supported Palladium complex displayed excellent catalytic activity in Heck coupling reaction of a series of activated alkenes and aryl halides and afforded the corresponding coupling products upto 96% isolated yield. After the reaction, the catalyst was easily recovered by simple filtration and recycled with excellent stability and activity even after 5 runs. This is the first report on the use of amidoxime functionalized PAN- Palladium (II) complex as a heterogeneous catalyst in Heck coupling reaction.
- Sruthi, Pambingal Rajan,Sarika, Vijayalekshmi,Suku, Arya,Krishnan, Aravind,Anas, Saithalavi
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- Highly efficient oxidation of alcohols to carboxylic acids using a polyoxometalate-supported chromium(iii) catalyst and CO2
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Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes.
- Han, Sheng,Wang, Ying,Wei, Yongge,Wu, Zhikang,Yu, Han
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p. 3150 - 3154
(2020/06/19)
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- Purification and Characterization of Anabaena flos-aquae Phenylalanine Ammonia-Lyase as a Novel Approach for Myristicin Biotransformation
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Phenylalanine ammonia-lyase (PAL) catalyzes the reversible deamination of phenylalanine to cinnamic acid and ammonia. Algae have been considered as biofactories for PAL production, however, biochemical characterization of PAL and its potency for myristicin biotransformation into MMDA (3-methoxy-4, 5-methylenedioxyamphetamine) has not been studied yet. Thus, PAL from Anabaena flos-aquae and Spirulina platensis has been purified, comparatively characterized and its affinity to transform myristicin was assessed. The specific activity of purified PAL from S. platensis (73.9 μmol/mg/min) and A. flos-aquae (30.5 μmol/mg/min) was increased by about 2.9 and 2.4 folds by gel-filtration comparing to their corresponding crude enzymes. Under denaturing-PAGE, a single proteineous band with a molecular mass of 64 kDa appeared for A. flos-aquae and S. platensis PAL. The biochemical properties of the purified PAL from both algal isolates were determined comparatively. The optimum temperature of S. platensis and A. flos-aquae PAL for forward or reverse activity was reported at 30oC, while the optimum pH for PAL enzyme isolated from A. flos-aquae was 8.9 for forward and reverse activities, and S. platensis PAL had maximum activities at pH 8.9 and 8 for forward and reverse reactions, respectively. Luckily, the purified PALs have the affinity to hydroaminate the myristicin to MMDA successfully in one step. Furthermore, a successful method for synthesis of MMDA from myristicin in two steps was also established. Gas chromatography-mass spectrometry (GC-MS) analysis was conducted to track the product formation.
- Abdel-Ghany, Afaf E.,Abdelaziz, Sahar,Arafa, Asmaa M.,El-Ayouty, Yassin,El-Dahmy, Samih I.,El-Sayed, Ashraf S. A.
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p. 622 - 632
(2020/05/08)
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- METHOD OF MAKING CYCLOBUTANE-1, 2-DIACIDS DEGRADABLE BUILDING BLOCKS FOR MATERIALS
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A method of making cyclobutane-1,2-diacid building blocks includes using trans-cinnamic acid in its beta form (head to head packing) and photodimerizing the trans-cinnamic acid to create cis-cyclobutane-1,2-dicarboxylic acid (CBDA-4).
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Page/Page column 2
(2020/07/04)
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- Selective Transfer Semihydrogenation of Alkynes with H2O (D2O) as the H (D) Source over a Pd-P Cathode
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We reported a selective semihydrogenation (deuteration) of numerous terminal and internal alkynes using H2O (D2O) as the H (D) source over a Pd-P alloy cathode at a lower potential. P-doping caused the enhanced specific adsorption of alkynes and the promoted intrinsic activity for producing adsorbed atomic hydrogen (H*ads) from water electrolysis. The semihydrogenation of alkynes could be accomplished at a lower potential with up to 99 % selectivity and 78 % Faraday efficiency of alkene products, outperforming pure Pd and commercial Pd/C. This electrochemical semihydrogenation of alkynes might proceed via a H*ads addition pathway rather than a proton-coupled electron transfer process. The decreased amount of H*ads at a lower potential and the more preferential adsorption of the Pd-P to C≡C π bond than C=C moiety resulted in the excellent alkene selectivity. This method was capable of producing mono-, di-, and tri-deuterated alkenes with up to 99 % deuterium incorporation.
- Liu, Cuibo,Lu, Siyu,Wang, Changhong,Wu, Yongmeng,Zhang, Bin
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supporting information
p. 21170 - 21175
(2020/09/11)
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- Donor-acceptor fluorophores as efficient energy transfer photocatalysts for [2 + 2] photodimerization
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Mild [2 + 2] photodimerization of enone substrates was induced by donor-acceptor fluorophores. Enone substrates were activated efficiently for anti-head to head dimerizations with a high yield (up to 83%) and high selectivity. The adjustable excited state potential also allows donor-acceptor fluorophores to be used for isomerization of the above substrates, confirming the potential of donor-acceptor fluorophores as energy transfer photocatalysts.
- Chen, Feng,Chen, Hao,Liu, Xue-Fen,Luo, Shu-Ping,Ren, Chen-Chao,Wu, Qing-An,Xu, Liang-Xuan,Yu, Xiao-Cong
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supporting information
p. 3707 - 3716
(2020/06/03)
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- Understanding the role played by protic ionic liquids (PILs) and the substituent effect for enhancing the generation of: Z-cinnamic acid derivatives
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Photoisomerization of a series of substituted E-cinnamic acids in MeCN in their acid forms and as their corresponding protic ionic liquids (PILs) with light of 300 nm is studied. The nature, strength, number, and position effects of substituents on the photochemical behavior of E-cinnamic derivatives are investigated. The photosensitization of the reaction in the presence of Michler's ketone is also studied at 366 nm and it demonstrates that the triplet-excited state is involved in the reaction. As the presence of n-butylamine needed to form the PILs significantly increases the photoproduct yields in all cases, the role of the PILs is also discussed. Thus, understanding of these fundamental aspects has allowed us to establish an excellent and practical synthetic protocol for successfully synthesizing Z-cinnamic acids. This journal is
- Rodríguez, Roció B.,Rodríguez, Roció B.,Zapata, Ramiro L.,Salum, Mariá L.,Salum, Mariá L.,Erra-Balsells, Rosa,Erra-Balsells, Rosa
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p. 819 - 830
(2020/07/03)
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- Acylated iridoid glycosides with hyaluronidase inhibitory activity from the rhizomes of Picrorhiza kurroa Royle ex Benth
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Seven new acylated iridoid glycosides, picrorhizaosides A–G (1–7), were isolated from the methanol extract of the rhizomes of Picrorhiza kurroa Royle ex Benth. (Plantaginaceae), in addition to six known iridoid glycosides (8–13). The structures of these new iridoids, including their stereochemistry, were determined based on chemical and physicochemical evidence derived from NMR and MS analysis. Of the isolates, picrorhizaosides D (4, IC50 = 43.4 μM) and E (5, 35.8 μM); picrosides I (8, 60.7 μM), II (9, 22.3 μM), and IV (11, 59.2 μM); and minecoside (13, 57.2 μM), exhibited a similar or stronger hyaluronidase inhibitory activity than those of the antiallergic medicines disodium cromoglycate (64.8 μM), ketotifen fumarate (76.5 μM), and tranilast (227 μM).
- Morikawa, Toshio,Nakanishi, Yusuke,Inoue, Naoki,Manse, Yoshiaki,Matsuura, Hideyuki,Hamasaki, Shinya,Yoshikawa, Masayuki,Muraoka, Osamu,Ninomiya, Kiyofumi
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- The production of 4-ethyltoluene: Via directional valorization of lignin
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4-Ethyltoluene is a very valuable chemical that is currently produced from fossil feedstocks. Production of 4-ethyltoluene from renewable and cheap lignin is of great significance. Herein, we report a new route to produce 4-ethyltoluene from lignin. It was discovered that RhCl3-LiI-LiBF4 was an efficient catalytic system for the reaction of lignin with CO to form 4-ethyltoluene. In the reaction, ethylbenzene was first formed via demethoxylation and depolymerization of lignin, which was further transformed into 4-ethyltoluene by methylation using methoxy from the lignin. The yield of 4-ethyltoluene could reach 9.5 wt% when GVL-lignin was used as the starting material. Interestingly, 5.2 wt% yield of 4-ethyltoluene was obtained when raw poplar was directly used as the starting material. As far as we know, the transformation of lignin with 4-ethyltoluene as the major product has not been reported. This work provides a new strategy to produce valuable aromatic compounds from renewable resources.
- Han, Buxing,Liu, Huizhen,Mei, Qingqing,Meng, Qinglei,Shen, Xiaojun,Xiang, Junfeng
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p. 2191 - 2196
(2020/04/20)
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- Carboxylation of Alkenyl Boronic Acids and Alkenyl Boronic Acid Pinacol Esters with CO2 Catalyzed by Cuprous Halide
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A cuprous halide catalysed carboxylation of alkenyl boronic acids and alkenyl boronic acid pinacol esters under CO2, affording the corresponding α, β-unsaturated carboxylic acids in good yield, has been developed. The potassium (E)-trifluoro(styryl)borate is also compatible with this reaction. This simple and efficient copper(I) catalytic system showed good functional group tolerance.
- Hong, Junting,Nayal, Onkar S.,Mo, Fanyang
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supporting information
p. 2813 - 2818
(2020/05/16)
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- Method for preparing alpha, beta-unsaturated carboxylic acid by reacting alkenyl boron compound with carbon dioxide under catalysis of cuprous halide
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The invention discloses a method for preparing alpha, beta-unsaturated carboxylic acid through a carboxylation reaction of an alkenyl boron compound and carbon dioxide under the catalysis of cuprous halide. According to the method, carbon dioxide is used as a C1 source, the cuprous halide is adopted for catalysis, and alkoxide serves as alkali to react in an organic solvent, so the method is simple and easy to implement, has a wide substrate application range, converts various alkenyl boron compounds such as alkenyl boric acid, alkenyl borate and borate into corresponding alpha, beta-unsaturated carboxylic acid under mild conditions, and has a very high yield. The obtained product alpha, beta-unsaturated carboxylic acid is an important intermediate for preparing fine chemical products suchas perfumes, insecticides and the like.
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Paragraph 0045-0046
(2020/06/17)
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- Pd Nanoparticles and Aminopolymers Confined in Hollow Silica Spheres as Efficient and Reusable Heterogeneous Catalysts for Semihydrogenation of Alkynes
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A yolk-shell nanostructured composite composed of Pd nanoparticles (NPs) and aminopolymers, poly(ethylenimine) (PEI), confined in hollow silica spheres which act as an efficient and stable heterogeneous catalyst for semihydrogenation of alkynes is reported herein. The yolk-shell nanostructured Pd-PEI-silica composite catalysts (Pd+PEI@HSS), consisting of Pd NPs core ca. 5-9 nm in diameter and a porous silica shell ca. 30-50 nm in shell thickness, are fabricated by a facile one-pot method using linear- or branched-type PEI (Mw = 1,800-2,500) as an organic template. On the basis of comprehensive structural analyses by FE-SEM, TEM, N2 physisorption, IR, TG, and Pd K-edge XAFS, we show that metal Pd NPs and PEI molecules are encapsulated in the hollow silica sphere with a size of ca. 100-160 nm. The Pd+PEI@HSS composite shows an activity at near room temperature in the liquid-phase hydrogenation of diphenylacetylene to selectively produce cis-stilbene with 95% yield, which outperforms those of the previously reported Pd/PEI and Lindlar catalysts. Interestingly, the catalyst encapsulating linear-type PEI provides a markedly high alkene selectivity in the semihydrogenation of phenylacetylene to produce styrene owing to the strong poisoning effect of linear PEI, which is clearly revealed by an isotope study using H2/D2/acetylene (or ethylene) gases. The catalyst synthesized with optimum silica shell thickness can be easily recovered and recycled without any loss of palladium species and PEI and retaining high activities and selectivities over multiple cycles owing to the ability of the protective effect of silica shell, rendering this material an efficient and stable catalyst for semihydrogenation of alkynes.
- Kuwahara, Yasutaka,Kango, Hiroto,Yamashita, Hiromi
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p. 1993 - 2006
(2019/02/19)
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- Semireduction of alkynoic acids via a transition metal-free α borylation-protodeborylation sequence
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A method for the semi-reduction of alkynoic acids through an α-borylation and subsequent protodeborylation mechanism has been developed. The transition metal-free protocol is achieved through the activation of bis(pinacolato)diboron by an in situ generated carboxylate moiety yielding aryl acrylic acids. Our studies demonstrate an unprecedented dual role for the carboxylate anion that involves the activation of the diboron reagent and a directing effect in the α-borylation.
- Verma, Astha,Grams, R. Justin,Rastatter, Brett P.,Santos, Webster L.
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supporting information
p. 2113 - 2117
(2019/02/25)
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- Organocatalyzed Aerobic Oxidation of Aldehydes to Acids
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The first example organocatalyzed aerobic oxidation of aldehydes to carboxylic acids in both organic solvent and water under mild conditions is developed. As low as 5 mol % N-hydroxyphthalimide was used as the organocatalyst, and molecular O2 was used as the sole oxidant. No transition metals or hazardous oxidants or cocatalysts were involved. A wide range of carboxylic acids bearing diverse functional groups were obtained from aldehydes, even from alcohols, in high yields.
- Dai, Peng-Fei,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 1393 - 1396
(2019/02/26)
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