- Mechanochemical Cycloreversion of Cyclobutane Observed at the Single Molecule Level
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Mechanochemical cycloreversion of cyclobutane is known from ultrasound experiments. It is, however, not clear which forces are required to induce the cycloreversion. In atomic force microscopy (AFM) experiments, on the other hand, it is notoriously difficult to assign the ruptured bond. We have solved this problem through the synthesis of tailored macrocycles, in which the cyclobutane mechanophore is bypassed by an ethylene glycol chain of specific length. This macrocycle is covalently anchored between a glass substrate and an AFM cantilever by polyethylene glycol linkers. Upon mechanical stretching of the macrocycle, cycloreversion occurs, which is identified by a defined length increase of the stretched polymer. The measured length change agrees with the value calculated with the external force explicitly included (EFEI) method. By using two different lengths for the ethylene glycol safety line, the assignment becomes unambiguous. Mechanochemical cycloreversion of cyclobutane is observed at forces above 1.7 nN.
- Pill, Michael F.,Holz, Katharina,Preu?ke, Nils,Berger, Florian,Clausen-Schaumann, Hauke,Lüning, Ulrich,Beyer, Martin K.
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- Flavonoid glycosides from Rhazya orientalis
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Six new flavonoid glycosides; quercetin 3-O-α-L-rhamnopyranosyl(1→6)-[α-L-rhamnopyranosyl (1→2)]-(4-O-trans-p-coumaroyl)-β-D-galactopyranoside-7- OαL-rhamnopyranoside (1), quercetin 3-O-α-L-rhamnopyranosyl(1→6)-[α-L-rhamnopyranosyl (1→2)]-(3-O-trans-p-cou
- Itoh, Atsuko,Kumashiro, Tomoko,Tanahashi, Takao,Nagakura, Naotaka,Nishi, Toyoyuki
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- Conjugation with dihydrolipoic acid imparts caffeic acid ester potent inhibitory effect on dopa oxidase activity of human tyrosinase
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Caffeic acid derivatives represent promising lead compounds in the search for tyrosinase inhibitors to be used in the treatment of skin local hyperpigmentation associated to an overproduction or accumulation of melanin. We recently reported the marked inhibitory activity of a conjugate of caffeic acid with dihydrolipoic acid, 2-S-lipoylcaffeic acid (LCA), on the tyrosine hydroxylase (TH) and dopa oxidase (DO) activities of mushroom tyrosinase. In the present study, we evaluated a more lipophilic derivative, 2-S-lipoyl caffeic acid methyl ester (LCAME), as an inhibitor of tyrosinase from human melanoma cells. Preliminary analysis of the effects of LCAME on mushroom tyrosinase indicated more potent inhibitory effects on either enzyme activities (IC50 = 0.05 ± 0.01 μM for DO and 0.83 ± 0.09 μM for TH) compared with LCA and the reference compound kojic acid. The inhibition of DO of human tyrosinase was effective (Ki = 34.7 ± 1.1 μM) as well, while the action on TH was weaker. Lineweaver–Burk analyses indicated a competitive inhibitor mechanism. LCAME was not substrate of tyrosinase and proved nontoxic at concentrations up to 50 μM. No alteration of basal tyrosinase expression was observed after 24 h treatment of human melanoma cells with the inhibitor, but preliminary evidence suggested LCAME might impair the induction of tyrosinase expression in cells stimulated with α-melanocyte-stimulating hormone. All these data point to this compound as a valuable candidate for further trials toward its use as a skin depigmenting agent. They also highlight the differential effects of tyrosinase inhibitors on the human and mushroom enzymes.
- Micillo, Raffaella,Sirés-Campos, Julia,García-Borrón, José Carlos,Panzella, Lucia,Napolitano, Alessandra,Olivares, Conchi
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- A drug delivery system based on switchable photo-controlled p-coumaric acid derivatives anchored on mesoporous silica
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A stimuli-responsive drug delivery system consisting of mesoporous silica with its surface modified by p-coumaric acid derivatives (CA) as photo-switchable ligands was studied for the delivery of the non-steroidal anti-inflammatory drug (NSAID) naproxen. For this purpose, MCM-41 mesoporous silica material was prepared and post-synthetically modified by the grafting of a triethoxysilyl derivative of p-coumaric acid, which undergoes a reversible photo-dimerization under UV irradiation and creates the “valves” on the surface of silica allowing targeted opening/closing of the pores. Naproxen was encapsulated into grafted MCM-41 and drug release studies were performed in two different media, in a simulated gastric fluid (pH = 2) and in a simulated body fluid (pH = 7.4). Differences in drug release were observed after irradiation of the material using UV light at λ = 365 nm (closed pore configuration) and UV light at λ = 254 nm (opened pore configuration).
- Beňová, Eva,Zeleňák, Vladimír,Halamová, Dá?a,Almá?i, Miroslav,Petrul'ová, Veronika,Psotka, Miroslav,Zeleňáková, Adriána,Ba?kor, Martin,Hornebecq, Virginie
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- Ultrafast dynamics of isolated model photoactive yellow protein chromophores: "Chemical perturbation theory" in the laboratory
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Pump-probe and pump-dump probe experiments have been performed on several isolated model chromophores of the photoactive yellow protein (PYP). The observed transient absorption spectra are discussed in terms of the spectral signatures ascribed to solvation, excited-state twisting, and vibrational relaxation. It is observed that the protonation state has a profound effect on the excited-state lifetime of p-coumaric acid. Pigments with ester groups on the coumaryl tail end and charged phenolic moieties show dynamics that are significantly different from those of other pigments. Here, an unrelaxed ground-state intermediate could be observed in pump-probe signals. A similar intermediate could be identified in the sinapinic acid and in isomerization-locked chromophores by means of pump-dump probe spectroscopy; however, in these compounds it is less pronounced and could be due to ground-state solvation and/or vibrational relaxation. Because of strong protonation-state dependencies and the effect of electron donor groups, it is argued that charge redistribution upon excitation determines the twisting reaction pathway, possibly through interaction with the environment. It is suggested that the same pathway may be responsible for the initiation of the photocycle in native PYP.
- Vengris, Mikas,Larsen, Delmar S.,Van Der Horst, Michael A.,Larsen, Olaf F. A.,Hellingwerf, Klaas J.,Van Grondelle, Rienk
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- Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites
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The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had
- Ali, Wajid,Anjana, S. S.,Bhattacharya, Trisha,Chandrashekar, Hediyala B.,Goswami, Nupur,Guin, Srimanta,Maiti, Debabrata,Panda, Sanjib,Prakash, Gaurav,Saha, Argha,Sasmal, Sheuli,Sinha, Soumya Kumar
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supporting information
p. 1929 - 1940
(2022/02/01)
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- TRPV3 inhibitor and preparation method thereof
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The invention discloses a TRPV3 inhibitor. The TRPV3 inhibitor is formed by sequentially connecting an R1 group, an R group and an R2 group, and the molecular structural general formula of the TRPV3 inhibitor is shown as a formula 1, wherein the structural formula of the R1 group is represented by a formula 2, R3 is selected from any one of -H, -OAc, -OH, a halogen group, -F3CO or a group containing a benzenesulfonyloxy group, and R4 is selected from any one of -H, -OAc or -OH; R1 and R2 are selected from alkyl or formula 3, R5 is selected from C or N, R6 is selected from any one of hydrogen, alkyl, halogen group or trifluoromethyl, R7 is selected from any one of hydrogen, halogen group, cyano group, nitro group or trifluoromethoxy group, and R8 is selected from hydrogen or halogen group. The invention also discloses a preparation method and application of the TRPV3 inhibitor. The TRPV3 inhibitor disclosed by the invention can specifically inhibit a TRPV3 ion channel and has huge scientific research and clinical values.
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Paragraph 0240; 0241; 0242; 0243; 0244; 0245; 0246
(2021/04/10)
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- Prenylated trans-cinnamic esters and ethers against clinical fusarium spp.: Repositioning of natural compounds in antimicrobial discovery
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Onychomycosis is a common nail infection mainly caused by species belonging to the F. oxysporum, F. solani, and F. fujikuroi species complexes. The aim of this study was to evaluate the in vitro susceptibility of six representative strains of clinically relevant Fusarium spp. toward a set of natural-occurring hydroxycinnamic acids and their derivatives with the purpose to develop naturally occurring products in order to cope with emerging resistance phenomena. By introducing a prenylated chain at one of the hydroxy groups of trans-cinnamic acids 1–3, ten prenylated derivatives (coded 4–13) were preliminarily investigated in solid Fusarium minimal medium (FMM). Minimal inhibitory concentration (MIC) and lethal dose 50 (LD50) values were then determined in liquid FMM for the most active selected antifungal p-coumaric acid 3,3′-dimethyl allyl ester 13, in comparison with the conventional fungicides terbinafine (TRB) and amphotericin B (AmB), through the quantification of the fungal growth. Significant growth inhibition was observed for prenylated derivatives 4–13, evidencing ester 13 as the most active. This compound presented MIC and LD50 values (62–250 μM and 7.8–125 μM, respectively) comparable to those determined for TRB and AmB in the majority of the tested pathogenic strains. The position and size of the prenylated chain and the presence of a free phenol OH group appear crucial for the antifungal activity. This work represents the first report on the activity of prenylated cinnamic esters and ethers against clinical Fusarium spp. and opens new avenues in the development of alternative antifungal compounds based on a drug repositioning strategy.
- Balmas, Virgilio,Carta, Paola,Casalini, Stefano,Chtioui, Wiem,Delogu, Giovanna,Dettori, Maria A.,Fabbri, Davide,Migheli, Quirico,Oufensou, Safa
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- Dirigent Proteins Guide Asymmetric Heterocoupling for the Synthesis of Complex Natural Product Analogues
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Phenylpropanoids are a class of abundant building blocks found in plants and derived from phenylalanine and tyrosine. Phenylpropanoid polymerization leads to the second most abundant biopolymer lignin while stereo- and site-selective coupling generates an array of lignan natural products with potent biological activity, including the topoisomerase inhibitor and chemotherapeutic etoposide. A key step in etoposide biosynthesis involves a plant dirigent protein that promotes selective dimerization of coniferyl alcohol, a common phenylpropanoid, to form (+)-pinoresinol, a critical C2 symmetric pathway intermediate. Despite the power of this coupling reaction for the elegant and rapid assembly of the etoposide scaffold, dirigent proteins have not been utilized to generate other complex lignan natural products. Here, we demonstrate that dirigent proteins from Podophyllum hexandrum in combination with a laccase guide the heterocoupling of natural and synthetic coniferyl alcohol analogues for the enantioselective synthesis of pinoresinol analogues. This route for complexity generation is remarkably direct and efficient: three new bonds and four stereocenters are produced from two different achiral monomers in a single step. We anticipate our results will enable biocatalytic routes to difficult-to-access non-natural lignan analogues and etoposide derivatives. Furthermore, these dirigent protein and laccase-promoted reactions of coniferyl alcohol analogues represent new regio- and enantioselective oxidative heterocouplings for which no other chemical methods have been reported.
- Kim, Stacie S.,Sattely, Elizabeth S.
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supporting information
p. 5011 - 5021
(2021/05/04)
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- Pd salen complex@CPGO as a convenient, effective heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions
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A Pd(II) Schiff base complex supported on graphene oxide nanosheets (Pd(II) salen@CPGO) has been synthesized and characterized by FT-IR, ICP-AES, XRD, SEM/EDX and TEM. The synthesized nanocatalyst has been found to be an efficient heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki coupling reactions. Pd(II) salen@CPGO could be separated and recovered easily from the reaction mixture and recycled several times without a discernible decrease in its catalytic activity. The construction of a solid sheet-supported Pd catalyst would be expected to be a promising system to perform heterogeneous catalytic reactions.
- Ghabdian, Mahdieh,Nasseri, Mohammad Ali,Allahresani, Ali,Motavallizadehkakhky, Alireza
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p. 1713 - 1728
(2018/05/25)
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- Synthesis and Evaluation of PPARδAgonists That Promote Osteogenesis in a Human Mesenchymal Stem Cell Culture and in a Mouse Model of Human Osteoporosis
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We synthesized a directed library of compounds to explore the structure-activity relationships of peroxisome proliferator-activated receptor δ(PPARδ) activation relative to mesenchymal stem cell (MSC) osteogenesis. Our scaffold used para-substituted cinnamic acids as a polar headgroup, a heteroatom and heterocycle core connecting units, and substituted phenyl groups for the lipophilic tail. Compounds were screened for their ability to increase osteogenesis in MSCs, and the most promising were examined for subunit specificity using a quantitative PPAR transactivation assay. Six compounds were selected for in vivo studies in an ovariectomized mouse model of human postmenopausal osteoporosis. Four compounds improved bone density in vivo, with two (12d and 31a) having activity comparable to that of GW0742, a well-studied PPARδ-selective agonist. 31a (2-methyl-4-[N-methyl-N-[5-methylene-4-methyl-2-[4-(trifluoromethyl)phenyl]thiazole]]aminocinnamic acid) had the highest selectivity for PPARδcompared to other subtypes, its selectivity far exceeding that of GW0742. Our results confirm that PPARδis a new drug target for possible treatment of osteoporosis via in situ manipulation of MSCs.
- Kress, Brian J.,Kim, Dong Hyun,Mayo, Jared R.,Farris, Jeffery T.,Heck, Benjamin,Sarver, Jeffrey G.,Andy, Divya,Trendel, Jill A.,Heck, Bruce E.,Erhardt, Paul W.
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p. 6996 - 7032
(2021/05/29)
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- Reduction of Electron-Deficient Alkenes Enabled by a Photoinduced Hydrogen Atom Transfer
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Direct hydrogen atom transfer from a photoredox-generated Hantzsch ester radical cation to electron-deficient alkenes has enabled the development of an efficient formal hydrogenation under mild, operationally simple conditions. The HAT-driven mechanism is supported by experimental and computational studies. The reaction is applied to a variety of cinnamate derivatives and related structures, irrespective of the presence of electron-donating or electron-withdrawing substituents in the aromatic ring and with good functional group compatibility. (Figure presented.).
- Larionova, Natalia A.,Ondozabal, Jun Miyatake,Cambeiro, Xacobe C.
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supporting information
p. 558 - 564
(2020/12/07)
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- BIVALENT LECA INHIBITORS TARGETING BIOFILM FORMATION OF PSEUDOMONAS AERUGINOSA
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The present invention relates to divalent compounds binding to LecA. The compounds are useful to block biofilm formation of Pseudomonas aeruginosa. The invention further relates to pharmaceutical compositions comprising these compounds and to therapeutic methods and uses of these compounds, in particular to therapeutic methods and uses for the treatment of Pseudomonas aeruginosa infections in a subject. The invention also relates to imaging of infections, such as biofilms produced by Pseudomonas aeruginosa, by using these divalent compounds.
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Page/Page column 48; 50-51
(2021/05/15)
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- Optimization of the reaction conditions for the synthesis of dihydrobenzofuran neolignans
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We have optimized the experimental conditions for the silver(I)-promoted oxidative coupling of methyl p-coumarate (I) and methyl ferulate (II), which is the most frequently used methodology to synthesize the bioactive dihydrobenzofuran neolignans 1 ((±)-trans-dehydrodicoumarate dimethyl ester) and 2 ((±)-trans-dehydrodiferulate dimethyl ester). Most of the tested conditions affected the conversion (i.e., the consumption of I and II) and the selectivity (i.e., the percentage of I and II that was converted into 1 and 2, respectively), so the optimized conditions were the ones that afforded the best balance between conversion and selectivity. Silver(I) oxide (0.5 equiv.) is the most efficient oxidant agent amongst the silver(I) reagents that were tested to convert methyl esters I and II into compounds 1 and 2, respectively. Acetonitrile, which has not yet been reported as a solvent for this reaction, provided the best balance between conversion and selectivity, besides being "greener" than other solvents that are more often employed (e.g., dichloromethane and benzene). Under the optimized conditions, the reaction time decreased from 20 to 4 h without significantly impacting the conversion and selectivity.
- Crotti, Ant?nio E. M.,Dias, Herbert J.,Rodrigues, Matheus L.
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- A donor-acceptor complex enables the synthesis of: E -olefins from alcohols, amines and carboxylic acids
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Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies require a transition metal catalyst, a ligand or an expensive photocatalyst, with the challenges of controlling the region- and stereoselectivities remaining. Herein, we present a fundamentally distinct strategy enabled by electron donor-acceptor (EDA) complexes, for the selective synthesis of olefins from these simple and easily available starting materials. The conversions took place via photoactivation of the EDA complexes of the activated substrates with alkali salts, followed by hydrogen atom elimination from in situ generated alkyl radicals. This method is operationally simple and straightforward and free of photocatalysts and transition-metals, and shows high regio- and stereoselectivities.
- Chen, Kun-Quan,Shen, Jie,Wang, Zhi-Xiang,Chen, Xiang-Yu
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p. 6684 - 6690
(2021/05/31)
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- Alkyl and aryl derivatives based on p-coumaric acid modification and inhibitory action against leishmania braziliensis and plasmodium falciparum
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In low-income populations, neglected diseases are the principal cause of mortality. Of these, leishmaniasis and malaria, being parasitic, protozoan infections, affect millions of people worldwide and are creating a public health problem. The present work evaluates the leishmanicidal and antiplasmodial action of a series of twelve p-coumaric acid derivatives. Of the tested derivatives, eight presented antiparasitic activities 1-3, 8-12. The hexyl p-coumarate derivative (9) (4.14 ± 0.55 μg/mL; selectivity index (SI) = 2.72) showed the highest leishmanicidal potency against the Leishmania braziliensis amastigote form. The results of the molecular docking study suggest that this compound inhibits aldehyde dehydrogenase (ALDH), mitogen-activated kinase protein (MPK4), and DNA topoisomerase 2 (TOP2), all of which are key enzymes in the development of Leishmania braziliensis. The data indicate that these enzymes interact via Van derWaals bonds, hydrophobic interactions, and hydrogen bonds with phenolic and aliphatic parts of this same compound. Of the other compounds analyzed, methyl p-coumarate (64.59 ± 2.89 μg/mL; IS = 0.1) demonstrated bioactivity against Plasmodium falciparum. The study reveals that esters presenting a p-coumarate substructure are promising for use in synthesis of derivatives with good antiparasitic profiles.
- De Sousa, Dami?o P.,Lopes, Susiany P.,Pérez-Castillo, Yunierkis,Robledo, Sara M.,Yepe, Lina M.
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supporting information
(2020/08/24)
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- Synthesis and evaluation of new 1,2,4-oxadiazole based trans- acrylic acid derivatives as potential PPAR-alpha/gamma dual agonist
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Diabetes is a ubiquitously a metabolic disorder and life-threatening disease. Peroxisome proliferator-activated receptors (PPARs) belong to the class of nuclear receptors which acts as transcription factors to regulate lipid and glucose metabolism. PPAR alpha/gamma dual agonists tend to corroborate the functions of both thiazolidinediones and fibrates and they hold substantial promise for ameliorating the type 2 diabetic treatments and providing potential therapeutic diabetic interventions. New 1,2,4-oxadiazole based trans- acrylic acid derivatives compounds possessing aryl/methylene linker in between pharmacophore head and lipophilic tail for dual PPAR-alpha/gamma agonists are studied. AutoDock Vina used for potential PPAR alpha/gamma dual agonists and 6 compounds 9a, 9g, 9 m, 9n, 9o, and 9r were identified comparable to PPAR gamma agonist Pioglitazone on the basis of their affinity scores and further their in-silico toxicity and in-silico ADME properties. The selected compounds showed better-calculated lipophilicity (iLogP) was found to be 0.92 to 3.19. Compound 9n and 9a were found to be most potent on both PPAR alpha and gamma receptors with EC50 of 0.07 ± 0.0006 μM, 0.06 ± 0.0005 μM and 0.781 ± 0.008 μM, 3.29 μM ± 0.03 respectively as better to pioglitazone having EC50 of 32.38 ± 0.2 and 38.03 ± 0.13 for both receptors. The in-vivo evaluation found to reduce the plasma glucose level and total cholesterol level significantly in diabetic rats compared to pioglitazone at 5 mg/kg/day dose for 7 days of treatment. Thus, trans- acrylic acid derivatives can be further developed as oral therapeutic agents for diabetic interventions as PPAR alpha/gamma dual agonists.
- Bhat, Sana,Bhat, Zahid Rafiq,Gupta, Jeena,Kaur, Jaskiran,Kaur, Paranjeet,Khatik, Gopal L.,Khurana, Navneet,Kumar, Rajan,Kumar, Rakesh,Tikoo, Kulbhushan
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- Coumaric acid derivatives as tyrosinase inhibitors: Efficacy studies through in silico, in vitro and ex vivo approaches
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p-Coumaric acid is a known inhibitor of tyrosinase, an enzyme involved in the initial steps of the melanin synthesis in human and other species. However, its low lipophilicity impairs its penetration through skin and efficacy as antimelanogenic agent indeed. Accordingly, this paper reports the assessment of several coumaric acid derivatives as tyrosinase inhibitors and antimelanogenic agents in in vitro, in silico and ex vivo assays. The compounds were designed with modifications in the aromatic and acid moieties of p-coumaric acid, being the coumarate esters the most promising derivatives. The compounds showed higher tyrosinase inhibitory activity (pIC50 3.7–4.2) than the parent acid, being compounds 1d, 1e and 1f the most potent inhibitors. Docking analysis showed that these esters are competitive inhibitors per se, and act independently of a redox mechanism as suggested by DPPH assays. Moreover, the esters showed efficacy in reducing the melanin deposition in human skin fragments at 0.1% concentration, especially compound 1e. In summary, there is an important equilibria between tyrosinase affinity and lipophilicity that must be considered to get effective antimelanogenic agents with adequate permeability in the skin.
- Fernandes, Jo?o Paulo S.,Ferrarini, Márcio,Mercaldi, Vitória Gallo,Nazato, Lucas Idacir Sbrugnera,Padovani, Giovana,Sufi, Bianca da Silva,Varela, Marina Themoteo
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- Coumaric acid analogues inhibit growth and melanin biosynthesis in Cryptococcus neoformans and potentialize amphotericin B antifungal activity
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Fungal infections are on the rise, since the imunocompromised population is increasing due to AIDS/HIV, organ transplant and chemotherapy. Many environmental and pathogenic fungi are able to accomplish melanin biosynthesis as a virulence factor to promote host invasion. Melanized cells are more resistant to radiation, oxidative and osmotic stresses; also melanin confers an advantage in vivo, since melanized cells are more resistant to phagocytic engulfment and oxidative stress caused by the host defense cells and by some antifungal drugs, such as fluconazole (FCZ) and amphotericin B (AmB). Brown, red or black melanin pigments can be produced by the polyketide pathway (DHN-melanin) or from dihydroxyphenols, such as L-DOPA (L-3,4-dihydroxyphenylalanine) and L-tyrosine by polyphenoloxidases. Among several pathogenic fungi, Cryptococcus neoformans is a melanized yeast that causes pneumonia and meningoencephalitis in immunocompromised patients. The knockout of the laccase genes or other interruptions on melanin biosynthetic pathway generates cryptococcal strains with attenuated virulence in an animal model. In this study 16 analogues of coumaric and cinnamic acid were evaluated as possible tyrosinase inhibitors. We have identified some valuable inhibitors of C. neoformans growth and melanin biosynthesis disruption agents. The results showed that coumaric acid derivatives (1a-c), the ketones (3a-b) and 2-allylphenol (7c) are significant inhibitors of tyrosinase and melanization of the fungus. Two analogues (1b and 3b) were selected as promising antimelanogenic agents to be combined with AmB, showing to promote 16-fold reduction in the AmB fungicidal concentration with no appreciable cytotoxicity to mammalian cells. The data suggest that inhibition of the melanin biosynthesis by these compounds may increase the susceptibility of the cells to the oxidative stress generated by AmB. In summary, our data show that C. neoformans can be a suitable model system to test novel inhibitors that target melanin biosynthesis, and novel compounds for adjunct therapy against C. neoformans were identified.
- Melhem, Marcia S. C.,Oliveira, Lidiane,Pascon, Renata C.,Vallim, Marcelo A.,Varela, Marina Themoteo,dos Santos, Alexandre Paes,Corrêa, Isabela Teresa Santos,Fernandes, Jo?o Paulo S.,Ferrarini, Márcio,Tempone, André Gustavo
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- Exploring bulky natural and natural-like periphery in the design of p-(benzyloxy)phenylpropionic acid agonists of free fatty acid receptor 1 (GPR40)
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Six derivatives of 3-phenylpropionic acid bearing various natural and natural-like, spatially defined peripheral motifs have been synthesized and evaluated in vitro for free fatty acid receptor 1 (FFA1) activation. Two frontrunner compounds (bearing a bornyl and cytosine groups) were evaluated in an oral glucose tolerance test in mice where both demonstrated the ability to sustain blood glucose levels following a glucose challenge. The bornyl compound displayed a somewhat superior, dose-dependent efficacy and, therefore, can be regarded as a lead compounds for further development as a therapeutic agent for type 2 diabetes mellitus. Its high affinity to FFA1 was rationalized by docking experiments.
- Gureev, Maxim,Krasavin, Mikhail,Kuranov, Sergey O.,Luzina, Olga A.,Onopchenko, Oleksandra,Pishel, Iryna,Salakhutdinov, Nariman F.,Zozulya, Sergey
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- Preparation method of esmolol hydrochloride intermediate
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The invention belongs to the field of organic synthesis of medicines, and particularly relates to a preparation method of a medicine esmolol hydrochloride intermediate for treating hypertension. The synthesis route provided by the invention comprises the following steps: reacting p-bromophenol with methyl acrylate in the presence of a palladium catalyst and a phosphine ligand to generate 3-(4-hydroxyphenyl) methyl acrylate; and hydrogenating the generated 3-(4-hydroxyphenyl) methyl acrylate in the presence of a palladium-carbon catalyst to obtain a target product methyl 4-hydroxyphenylpropionate. The method has the advantages of short reaction steps, cheap and accessible raw materials, simple technique and convenience of operation, and does not need special reaction conditions, thereby being more suitable for industrial production.
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Paragraph 0041-0043; 0046-0048
(2020/09/16)
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- Structure?Activity Relationships of Cinnamate Ester Analogues as Potent Antiprotozoal Agents
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Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub-tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate ester analogues and their structure-activity relationships. In general, Leishmania donovani and Trypanosoma brucei were quite susceptible to the compounds in a structure-dependent manner. Detailed analysis revealed a key role of the substitution pattern on the aromatic ring and a marked effect of the side chain on the activity against these two parasites. The high antileishmanial potency and remarkable selectivity of the nitro-aromatic derivatives suggested them as promising candidates for further studies. On the other hand, the high in vitro potency of catechol-type compounds against T. brucei could not be extrapolated to an in vivo mouse model.
- Bernal, Freddy A.,Kaiser, Marcel,Wünsch, Bernhard,Schmidt, Thomas J.
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- Palladium-Based Catalysts Supported by Unsymmetrical XYC–1 Type Pincer Ligands: C5 Arylation of Imidazoles and Synthesis of Octinoxate Utilizing the Mizoroki–Heck Reaction
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A series of new unsymmetrical (XYC–1 type) palladacycles (C1–C4) were designed and synthesized with simple anchoring ligands L1–4H (L1H = 2-((2-(4-methoxybenzylidene)-1-phenylhydrazinyl)methyl)pyridine, L2H = N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazono)methyl)aniline, L3H = N,N-diethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazono)methyl) aniline and L4H = 4-(4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazono) methyl)phenyl)morpholine H = dissociable proton). Molecular structure of catalysts (C1–C4) were further established by single X-ray crystallographic studies. The catalytic performance of palladacycles (C1–C4) was explored with the direct Csp2–H arylation of imidazoles with aryl halide derivatives. These palladacycles were also applied for investigating of Mizoroki–Heck reactions with aryl halides and acrylate derivatives. During catalytic cycle in situ generated Pd(0) nanoparticles were characterized by XPS, SEM and TEM analysis and possible reaction pathways were proposed. The catalyst was employed as a pre-catalyst for the gram-scale synthesis of octinoxate, which is utilized as a UV-B sunscreen agent.
- Maji, Ankur,Singh, Ovender,Singh, Sain,Mohanty, Aurobinda,Maji, Pradip K.,Ghosh, Kaushik
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p. 1596 - 1611
(2020/04/29)
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- Mushroom Tyrosinase-Based Enzyme Inhibition Assays Are Not Suitable for Bioactivity-Guided Fractionation of Extracts
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Tyrosinase (Tyr) catalyzes the rate-limiting step of melanogenesis in human skin and is thus the main target for treating pigmentation disorders today. This has led to an increased research interest in Tyr inhibitors during the last decades, with a frequent focus on polyphenols. In the early stages of drug discovery, it is typical to avoid the high costs of human Tyr by using the more economic mushroom tyrosinase (mh-Tyr). Since some polyphenols are accepted as substrates by mh-Tyr, the present study aimed to more generally investigate this enzyme's specificity toward polyphenols and to discuss its significance in the context of bioactivity-guided fractionation. Mh-Tyr substrates can change the sample color during an inhibition assay, leading to unreliable inhibition constants or to the discontinuation of a bioactivity-guided fractionation campaign. A data set of 56 natural products was investigated and classified into assay interferers (AIs) and noninterferers, using a spectrophotometric and an LC-ESIHRMS assay. Based on these experimental findings, structure-activity relationships defining AIs were deduced and implemented into an in silico tool that will allow for rapid prescreening in the future. We anticipate that these results will aid in the search for new Tyr inhibitors and contribute to the understanding of this enzyme, as well as its optimal use in pharmacological research.
- Mayr, Fabian,Sturm, Sonja,Ganzera, Markus,Waltenberger, Birgit,Martens, Stefan,Schwaiger, Stefan,Schuster, Daniela,Stuppner, Hermann
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supporting information
p. 136 - 147
(2019/01/21)
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- Design, synthesis and antitumor evaluation of novel celastrol derivatives
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On the basis of the hybridization strategy of natural products, a total of 32 novel celastrol hybrids were designed, synthesized and evaluated for their antitumor activities. Most of these derivatives exihibited significant antiproliferative activities compared to celastrol, among which compound 29 displayed the strongest inhibitory capability [IC50 = 0.15 ± 0.03 μM (A549),0.17 ± 0.03 μM (MCF-7), 0.26 ± 0.02 μM (HepG2)], which exhibited equal or superior anti-cancer activities in comparison to 2-cyano-3,12-dioxoolean-1,9 (11)-dien-28-oic acid methyl ester (CDDO-Me). The mechanism of pharmacological research indicated that 29 possessed the ability to disrupt Hsp90-Cdc37 complex which was stronger than celastrol. Meanwhile, compound 29 could induce abnormal regulation of clients (p-Akt and Cdk4) of Hsp90 and cell cycle arrest at G0/G1 phase in a concentration-dependent manner. In addition, compound 29 could also induce cell apoptosis through the death receptor pathway on A549 cells. Taken together, our results demonstrated that 29 might be a promising novel candidate for further druggability research.
- Xu, Manyi,Li, Na,Zhao, Zihao,Shi, Zhixian,Sun, Jianbo,Chen, Li
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p. 265 - 276
(2019/05/04)
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- Hydroxamic Acid Derivatives of β-Carboline/Hydroxycinnamic Acid Hybrids Inducing Apoptosis and Autophagy through the PI3K/Akt/mTOR Pathways
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Naturally occurring β-carbolines are known to have antitumor activities but with limited effectiveness. In order to improve their efficacy, a series of new hydroxamic-acid-containing β-carbolines connected via a hydroxycinnamic acid moitey (12a-f) were developed to incorporate histone deacetylase (HDAC) inhibition for possible synergistic effects. When evaluated in in vitro assays, most of the analogues showed significant antitumor activities against four human cancer cells. In particular, 12b showed the highest cytotoxic potency of the series, including drug-resistant Bel7402 cells, but had minimal effect on normal hepatic LO2 cells. These compounds also showed excellent inhibitory effects against HDAC1/6, which appear to contribute greatly to their antiproliferative properties. Compound 12b enhanced the acetylation levels of histone H3 and α-tubulin and induced greater cancer cell apoptosis than the FDA-approved HDAC inhibitor SAHA by regulating expression of apoptotic proteins Bax, Bcl-2, and caspase 3. Importantly, 12b also induced a significant amount of autophagic flux activity in Bel7402 cells by increasing the expression of Beclin-1 and LC3-II proteins and decreasing that of LC3-I and p62. Finally, 12b significantly inhibited PI3K/Akt/mTOR signaling, an important cell-growth-promoting pathway aberrantly activated in many cancers. Together, the results suggest that these hydroxamic-acid-containing β-carboline derivatives may be new leads for the discovery of agents for the treatment of human carcinoma cancers.
- Ling, Yong,Li, Yangyang,Zhu, Rui,Qian, Jianqiang,Liu, Ji,Gao, Weijie,Meng, Chi,Miao, Jiefei,Xiong, Biao,Qiu, Xiaodong,Ling, Changchun,Dai, Hong,Zhang, Yanan
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p. 1442 - 1450
(2019/07/05)
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- Antifungal activity of cinnamic acid and benzoic acid esters against Candida albicans strains
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Candida albicans is an important opportunistic fungal pathogen capable of provoking infection in humans. In the present study, we evaluated the antifungal effect of 23 ester derivatives of the cinnamic and benzoic acids against 3 C. albicans strains (ATCC-76645, LM-106 and LM-23), as well as discuss their Structure–Activity Relationship (SAR). The antifungal assay results revealed that the screened compounds exhibited different levels of activity depending on structural variation. Among the ester analogues, methyl caffeate (5) and methyl 2-nitrocinnamate (10) were the analogues that presented the best antifungal effect against all C. albicans strains, presenting the same MIC values (MIC?=?128?μg/mL), followed by methyl biphenyl-2-carboxylate (21) (MIC?=?128, 128 and 256?μg/mL for C. albicans LM-106, LM-23, and ATCC-76645, respectively). Our results suggest that certain molecular characteristics are important for the antifungal action.
- Lima, Tamires C.,Ferreira, Alana R.,Silva, Daniele F.,Lima, Edeltrudes O.,de Sousa, Dami?o P.
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p. 572 - 575
(2017/09/30)
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- Heterotelechelic Polymers by Ring-Opening Metathesis and Regioselective Chain Transfer
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Heterotelechelic polymers were synthesized by a kinetic telechelic ring-opening metathesis polymerization method relying on the regioselective cross-metathesis of the propagating Grubbs’ first-generation catalyst with cinnamyl alcohol derivatives. This procedure allowed the synthesis of hetero-bis-end-functional polymers in a one-pot setup. The molecular weight of the polymers could be controlled by varying the ratio between cinnamyl alcohol derivatives and monomer. The end functional groups can be changed using different aromatically substituted cinnamyl alcohol derivatives. Different monomers were investigated and the presence of the functional groups was shown by NMR spectroscopy and MALDI-ToF mass spectrometry. Labeling experiments with dyes were conducted to demonstrate the orthogonal addressability of both chain ends of the heterotelechelic polymers obtained.
- Liu, Peng,Yasir, Mohammad,Ruggi, Albert,Kilbinger, Andreas F. M.
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supporting information
p. 914 - 917
(2018/01/01)
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- Novel neuroprotective lead compound ligustrazine derivative mass spectrometry fragmentation rule and metabolites in rats by LC/LTQ-orbitrap MS
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The neuroprotective evaluation of ligustrazine derivatives has become a research focus all over the world. A novel ligustrazine derivative, (3,5,6-Trimethylpyrazin-2-yl)methyl(E)-3-(4-((3,5,6-trimethylpyrazin-2-l)methoxy)phenyl)acrylate (T-CA), has shown protective effects against CoCl2-induced neurotoxicity in a differentiated PC12 cell model and middle cerebral artery occlusion (MCAO) model in our previous studies. However, nearly none of the parent drugs existed after rapid metabolism due to uncertain reasons. Thus, the fragmentation regularities of mass spectra, and metabolites, of T-CA in rats were examined using liquid chromatography-electrospray ionizationion trap mass spectrometry (LC/LTQ-Orbitrap MS) in this research. The main fragment ion, mass spectrum characteristics, and the structural information were elucidated. When compared with a blank sample, we identified five kinds of T-CA metabolites, including three phase I metabolites and two phase II metabolites. The results showed that the metabolic pathways of T-CA in rats via oral administration were hydrolysis (ether bond rupture, ester bond rupture), oxidation, reduction, glucose aldehyde acidification, etc. In addition, three main metabolites were synthesized and their structures were identified by superconducting high-resolution NMR and high-resolution mass spectroscopy (HR-MS). The neuroprotective activity of these metabolites was validated in a PC12 cell model. One of the metabolites (M2) showed significant activity (EC50 = 9.67 μM), which was comparable to the prototype drug T-CA (EC50 = 7.97 μM). The current study provides important information for ligustrazine derivatives, pertaining to the biological conversion process in vivo.
- Zhang, Xinyu,Zhao, Rui,Chen, Meng,Ma, Tao,Wu, Gaorong,Xue, Nannan,Li, Guoliang,Wang, Hui,Fang, Kang,Zhang, Wenxi,Wang, Penglong,Lei, Haimin
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- Synthesis of Phenols: Organophotoredox/Nickel Dual Catalytic Hydroxylation of Aryl Halides with Water
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A highly effective hydroxylation reaction of aryl halides with water under synergistic organophotoredox and nickel catalysis is reported. The OH group of the resulting phenols originates from water, following deprotonation facilitated by an intramolecular base group on the ligand. Significantly, aryl bromides as well as less reactive aryl chlorides served as effective substrates to afford phenols with a wide range of functional groups. Without the need for a strong inorganic base or an expensive noble-metal catalyst, this process can be applied to the efficient preparation of diverse phenols and enables the hydroxylation of multifunctional pharmaceutically relevant aryl halides.
- Yang, Liu,Huang, Zhiyan,Li, Gang,Zhang, Wei,Cao, Rui,Wang, Chao,Xiao, Jianliang,Xue, Dong
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supporting information
p. 1968 - 1972
(2018/02/06)
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- Synthesis and Mesogenic Properties of Liquid Crystals Based on Cholesterol and Cinnamic Acid Derivatives
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A group of new mesomorphic compounds with cholesterol-based, which have derivative of the cinnamic acid, with different lengths of terminal alkoxy chains, are synthesized and characterized. The mesomorphic properties were investigated by DSC and POM. All target compounds showed a cholesteric phase. For 12-TC and 14-TC besides a cholesteric phase, also revealed a SmA* phase. The experimental results demonstrated that with the increase in the terminal chain lengths, the thermal stability of the smectic mesophases of these liquid crystals was increased, and these compounds shows brilliant color changes in the temperature ranges of cholesteric phase.
- Zong, Xuenan,Wu, Changcheng
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- Selective catalytic tailoring of the H unit in herbaceous lignin for methyl: P -hydroxycinnamate production over metal-based ionic liquids
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Selective valorization of lignin to achieve high value and commodity chemicals is attracting increasing attention. In this work, an efficient and reusable metal-based ionic liquid (MBIL) was developed for the selective tailoring of p-coumaric acid ester (pCA), a typical p-hydroxyphenyl (H) unit, into methyl p-hydroxycinnamate (MPC). Under optimized conditions and in the presence of catalyst [Bmim][FeCl4], a volatile aromatic product of 10.5 wt% was obtained, of which, 70.5% separated as pure MPC with an isolated yield of 71.1 mg g-1. FT-IR, 13C NMR, ANO and 2D HSQC demonstrated that the H unit was preferentially tailored from lignin, of which, 86.0 wt% of the H structure unit is cut off from lignin, with 70.6% being selectively converted to MPC. Further investigation demonstrated that MBIL prefers to tailor ester bonds compared to ether bonds using model compounds, and the superior catalytic ester bond cleavage performance exhibited by [Bmim][FeCl4] can be ascribed to the relatively narrow energy gap between the lignin ester bond and [FeCl4]- anion and to the comparatively low absolute binding energy between the cation and anion through DFT calculations.
- Li, Zhangmin,Cai, Zhenping,Zeng, Qiang,Zhang, Tian,France, Liam John,Song, Changhua,Zhang, Yaqin,He, Hongyan,Jiang, Lilong,Long, Jinxing,Li, Xuehui
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p. 3743 - 3752
(2018/08/21)
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- Synthesis and antioxidant activity of caffeic acid derivatives
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A series of caffeic acid derivatives were synthesized via a modified Wittig reaction which is a very important tool in organic chemistry for the construction of unsaturated carbon–carbon bonds. All reactions were performed in water medium at 90?C. The aqueous Wittig reaction worked best when one unprotected hydroxyl group was present in the phenyl ring. The olefinations in the aqueous conditions were also conducted with good yields in the presence of two unprotected hydroxyl groups. When the number of the hydroxyl groups was increased to three, the reaction yields were worse, and the derivatives 12, 13, and 18 were obtained with 74%, 37%, and 70% yields, respectively. Nevertheless, the Wittig reaction using water as the essential medium is an elegant one-pot synthesis and a greener method, which can be a safe alternative for implementation in organic chemistry. The obtained compounds were tested for their antioxidant activity, and 12, 13, and 18 showed the highest activities. Moreover, all synthesized compounds displayed no cytotoxicity, and can therefore be used in the pharmaceutical or cosmetic industry.
- Sidoryk, Katarzyna,Jaromin, Anna,Filipczak, Nina,Cmoch, Piotr,Cybulski, Marcin
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- General and Efficient Intermolecular [2+2] Photodimerization of Chalcones and Cinnamic Acid Derivatives in Solution through Visible-Light Catalysis
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[2+2] Photocycloaddition, for example, the dimerization of chalcones and cinnamic acid derivatives, is a unique strategy to construct cyclobutanes, which are building blocks for a variety of biologically active molecules and natural products. However, most attempts at the above [2+2] addition have focused on solid-state, molten-state, or host–guest systems under ultraviolet-light irradiation in order to overcome the competition of facile geometric isomerization of nonrigid olefins. We report a general and simple method to realize the intermolecular [2+2] dimerization reaction of these acyclic olefins to construct cyclobutanes in a highly regio- and diastereoselective manner in solution under visible light, which provides an efficient solution to a long-standing problem.
- Lei, Tao,Zhou, Chao,Huang, Mao-Yong,Zhao, Lei-Min,Yang, Bing,Ye, Chen,Xiao, Hongyan,Meng, Qing-Yuan,Ramamurthy, Vaidhyanathan,Tung, Chen-Ho,Wu, Li-Zhu
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p. 15407 - 15410
(2017/11/13)
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- Regioselective Enzymatic Carboxylation of Bioactive (Poly)phenols
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In order to extend the applicability of the regioselective enzymatic carboxylation of phenols, the substrate scope of o-benzoic acid (de)carboxylases has been investigated towards complex molecules with an emphasis on flavouring agents and polyphenols possessing antioxidant properties. o-Hydroxycarboxylic acid products were obtained with perfect regioselectivity, in moderate to excellent yields. The applicability of this method was proven by the regioselective bio-carboxylation of resveratrol on a preparative scale with 95% yield. (Figure presented.).
- Plasch, Katharina,Resch, Verena,Hitce, Julien,Pop?oński, Jaros?aw,Faber, Kurt,Glueck, Silvia M.
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supporting information
p. 959 - 965
(2017/03/27)
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- Characterization and Elimination of Undesirable Protein Residues in Plant Cell Wall Materials for Enhancing Lignin Analysis by Solution-State Nuclear Magnetic Resonance Spectroscopy
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Protein polymers exist in every plant cell wall preparation, and they interfere with lignin characterization and quantification. Here, we report the structural characterization of the residual protein peaks in 2D NMR spectra in corn cob and kenaf samples and note that aromatic amino acids are ubiquitous and evident in spectra from various other plants and tissues. The aromatic correlations from amino acid residues were identified and assigned as phenylalanine and tyrosine. Phenylalanine's 3/5 correlation peak is superimposed on the peak from typical lignin p-hydroxyphenyl (H-unit) structures, causing an overestimation of the H units. Protein contamination also occurs when using cellulases to prepare enzyme lignins from virtually protein-free wood samples. We used a protease to remove the protein residues from the ball-milled cell walls, and we were able to reveal H-unit structures in lignins more clearly in the 2D NMR spectra, providing a better basis for their estimation.
- Kim, Hoon,Padmakshan, Dharshana,Li, Yanding,Rencoret, Jorge,Hatfield, Ronald D.,Ralph, John
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p. 4184 - 4195
(2017/12/26)
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- COMPOUND APPLICABLE TO PHOTOALIGNMENT METHOD AND ITS PHOTOSENSITIVE POLYMER
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PURPOSE: A photosensitive polymer prepared by polymerizing a compound which is proper for photoalignment is provided to prevent static electricity and to manufacture liquid crystal alignment film with high optical uniformity. CONSTITUTION: A compound which is proper to photoalignment is denoted by chemical formula 1. A photosensitive polymer is used by polymerizing the compound of chemical formula 1. A liquid crystal alignment film is manufactured using the photoalignment agent. A liquid crystal display device is manufactured using the photoalignment agent.
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Paragraph 0179-0181; 0184-0185
(2017/09/29)
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- Palladium nanoparticles immobilized on amphiphilic and hyperbranched polymer-functionalized magnetic nanoparticles: An efficient semi-heterogeneous catalyst for Heck reaction
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To address the obstacles facing the use of palladium-based homogeneous and heterogeneous catalysts in C─C cross-coupling reactions, a novel semi-heterogeneous support was developed based on hyperbranched poly(ethylene glycol)-block-poly(citric acid)-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@PCA-b-PEG). Because of the surface modification of the Fe3O4 nanoparticles with amphiphilic and hyperbranched polymers (PCA-b-PEG), these hybrid materials are not only soluble in a wide range of solvents (e.g. water, ethanol and dimethylformamide) but also are able to trap Pd2+ ions via complex formation of free carboxyl groups of the PCA dendrimer with metal ions. The reduction of trapped palladium ions in the dendritic shell of Fe3O4@PCA-b-PEG leads to immobilized palladium nanoparticles. The morphology and structural features of the catalyst were characterized using various microscopic and spectroscopic techniques. The catalyst was effectively used in the palladium-catalysed Mizoroki–Heck coupling reaction in water as a green solvent. In addition, the catalyst can be easily recovered from the reaction mixture by applying an external magnetic field and reused for more than ten consecutive cycles without much loss in activity, exhibiting an example of a sustainable and green methodology.
- Tabatabaei Rezaei, Seyed Jamal,Shamseddin, Azin,Ramazani, Ali,Mashhadi Malekzadeh, Asemeh,Azimzadeh Asiabi, Pegah
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- Pd/Indanone-Based Ligands: An Efficient Catalyst System for Ullmann-Type, Suzuki-Miyaura, and Mizoroki-Heck Cross-Coupling Reactions with Aryl Tosylates and Aryl Halides
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2-Hydroxyindan-1-ones have been efficiently synthesized and successfully applied as ligands in Pd-catalyzed Ullmann type, Suzuki-Miyaura, and Mizoroki-Heck cross-coupling reactions with aryl tosylates and aryl halides. The ligands are air- and moisture-stable and have shown high catalytic activity with Pd(OAc) 2 in these cross-coupling reactions. The system tolerates a variety of functional groups in the product and can be re-used at least three times with maximum efficiency..
- Waheed, Mohammed,Ahmed, Naseem
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p. 4372 - 4382
(2017/09/12)
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- Pd0.09Ce0.91O2-Δ: A sustainable ionic solid-solution precatalyst for heterogeneous, ligand free Heck coupling reactions
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A quick and easy method for the preparation of Pd2+ metal ion substituted in ceria, Pd0.09Ce0.91O2-δ solid solution oxide, is described. The Pd0.09Ce0.91O2-δ solid solution oxide was fully characterized by XRD, ICP-OES, BET, XPS, SEM, EDX, TEM, TGA and Raman spectroscopy. All characterization techniques strongly suggested that Pd2+ was successfully incorporated into the lattice structure of ceria. The effect of the reaction conditions on the catalytic properties of the Pd0.09Ce0.91O2-δ solid solution catalyst initially was studied in detail with the model Heck reaction of iodobenzene and methylacrylate to obtain optimum reaction conditions. The Pd0.09Ce0.91O2-δ solid solution catalyst then afforded substituted alkenes in good to excellent yields under these optimum reaction conditions. Steric and electronic effects were also studied, and were found to influence the catalytic activity. Characterization of the used catalyst suggests that Pd2+ in Pd0.09Ce0.91O2-δ is reduced in situ to Pd0 when employed in the Heck cross-coupling reactions. The catalyst was easily recovered by centrifuge and reused three times without significant loss of catalytic efficiency.
- Mpungose, Philani P.,Sehloko, Neo I.,Dasireddy, Venkata D.B.C.,Mahadevaiah, Narayanappa,Maguire, Glenn E.,Friedrich, Holger B.
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- Microwave-Assisted Synthesis of Phenylpropanoids and Coumarins: Total Synthesis of Osthol
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Herein we describe a one-pot microwave-assisted method for the synthesis of cinnamic acid and coumarin derivatives. The synthesis begins with an aldehyde synthon, and the chosen reaction conditions determine whether a cinnamic acid or coumarin derivative is formed. A regioselective Claisen rearrangement was also efficiently incorporated into the synthetic sequence to further increase the complexity of the product. Notably, this approach provides high product yields and selectivities without the need of a phenol protecting group.
- Konrádová, Daniela,Kozubíková, Hana,Dole?al, Karel,Pospí?il, Ji?í
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supporting information
p. 5204 - 5213
(2017/09/29)
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- Tandem Ring-Opening–Ring-Closing Metathesis for Functional Metathesis Catalysts
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Use of a tandem ring-opening–ring-closing metathesis (RORCM) strategy for the synthesis of functional metathesis catalysts is reported. Ring opening of 7-substituted norbornenes and subsequent ring-closing metathesis forming a thermodynamically stable 6-membered ring lead to a very efficient synthesis of new catalysts from commercially available Grubbs’ catalysts. Hydroxy functionalized Grubbs’ first- as well as third-generation catalysts have been synthesized. Mechanistic studies have been performed to elucidate the order of attack of the olefinic bonds. This strategy was also used to synthesize the ruthenium methylidene complex.
- Nagarkar, Amit A.,Yasir, Mohammad,Crochet, Aurelien,Fromm, Katharina M.,Kilbinger, Andreas F. M.
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supporting information
p. 12343 - 12346
(2016/10/13)
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- Synthesis and anticancer activities of glycyrrhetinic acid derivatives
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A total of forty novel glycyrrhetinic acid (GA) derivatives were designed and synthesized. The cytotoxic activity of the novel compounds was tested against two human breast cancer cell lines (MCF-7, MDA-MB-231) in vitro by the MTT method. The evaluation results revealed that, in comparison with GA, compound 42 shows the most promising anticancer activity (IC50 1.88 ± 0.20 and 1.37 ± 0.18 μM for MCF-7 and MDA-MB-231, respectively) and merits further exploration as a new anticancer agent.
- Li, Yang,Feng, Ling,Song, Zhi-Fang,Li, Hai-Bei,Huai, Qi-Yong
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- Study of mesomorphism and its relation to molecular structure with special reference to central bridges viz. -COO- and -CH=CH-COO- of the homologous series
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Two ester homologous series of mesogens, viz., Methyl-p-(p′-n-alkoxy benzoyloxy) cinnamates (X) and Methyl-p-(p′-n-alkoxy cinnamoyloxy) cinnamates (Y) being structurally similar are discussed. Both (X) and (Y) differ in respect of central bridges linking two phenyl rings. Only enantiotropic nematogenic character is observed without exhibition of any smectic character by all members of series (X) and (Y). Thermal stability of series (X) is relatively low as compared to (Y), but nematogenic mesophase lengths are of reverse order. Solid-nematic/solid-isotropic and nematic-isotropic transition curves in the phase diagrams behave in normal manner.
- Sharma,Solanki,Patel,Patel
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p. 137 - 145
(2016/03/01)
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- Styrylsulfonates and -Sulfonamides through Pd-Catalysed Matsuda–Heck Reactions of Vinylsulfonic Acid Derivatives and Arenediazonium Salts
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Arene diazonium salts undergo Matsuda–Heck reactions with vinylsulfonates and -sulfonamides to give styrylsulfonic acid derivatives in high to excellent yields and with high to excellent selectivities. By quantifying the evolution of nitrogen over time in a gas-meter apparatus, the reactivities of ethylvinylsulfonate and the benchmark olefin methyl acrylate were compared for an electron-rich and an -deficient arene diazonium salt. Tertiary sulfonamides react in Matsuda–Heck couplings with high conversions, but require long reaction times, which prevents the determination of kinetic data through the measurement of nitrogen evolution. Secondary sulfonamides were found to be unreactive. From these results, the following order of reactivity could be deduced: H2C=CHCO2Me > H2C=CHSO2OEt > H2C=CHSO2N(Me)Bn >> H2C=CHSO2NHBn. Through the Matsuda–Heck coupling of 5-indolyldiazonium salt and a tertiary vinylsulfonamide, the synthesis of the C-5-substituted indole part of the antimigraine drug naratriptan was accomplished in high yield.
- Schmidt, Bernd,Wolf, Felix,Brunner, Heiko
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p. 2972 - 2982
(2016/07/11)
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- METHODS OF PRODUCING SUGAR-SPHINGOSINE AND SPHINGO BASE
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PROBLEM TO BE SOLVED: To provide a method of producing sphingo base in which sugar-ceramide is used as a row material, a method by which sugar-sphingosine can be selectively produced with high yield by hydrolyzing sugar-ceramide, and a method by which sphingo base can be selectively produced with high yield by hydrolyzing sugar-sphingosine. SOLUTION: The method of producing sugar-sphingosine is provided which includes obtaining sugar-sphingosine by hydrolyzing sugar-ceramide. The hydrolysis includes heating sugar-ceramide at a temperature of 100°C or higher under the presence of aqueous solution of alcoholic organic compound and alkali metal hydroxide, having a boiling point of 100°C or higher to obtain sugar-sphingosine. The method of producing sphingo base is also provided which includes obtaining sphingo base by hydrolyzing sugar-sphingosine. The hydrolysis includes causing sugar hydrolase to act on sugar-sphingosine to obtain sphingo base, and sugar-sphingosine may be produced by the method. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0053; 0054
(2016/12/01)
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- Photoreactive polymer and its preparation method
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Provided are a photoreactive polymer that includes a multi-cyclicmulticyclic compound at as its main chain and a method of preparing the same. The photoreactive polymer exhibits excellent thermal stability since it includes a multi-cyclicmulticyclic compound having a high glass transition temperature at as its main chain. In addition, the photoreactive polymer has a relatively large vacancy so that a photoreactive group can move relatively freely in the main chain therein. As a result, a slow photoreaction rate, which is a disadvantage of a conventional polymer material used to form an alignment layer for a liquid crystal display device, can be overcome.
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Paragraph 0099; 0100
(2016/10/09)
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- Discovery of neurotrophic agents based on hydroxycinnamic acid scaffold
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The number of people affected by neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease is rapidly increasing owing to the global increase in life expectancy. Small molecules with neurotrophic effects have great potential for management of these neurological disorders. In this study, different (C1–C12) alkyl ester derivatives of hydroxycinnamic acids (HCAs) were synthesized (a total of 30 compounds). The neurotrophic capacity of the test compounds was examined by measuring promotion of survival in serum-deprived conditions and enhancement of nerve growth factor (NGF)-induced neurite outgrowth in PC12 neuronal cells. p-Coumaric, ferulic, and sinapic acids and their esters did not alter cell survival, while caffeic acid and all its alkyl esters, especially decyl and dodecyl caffeate, significantly promoted neuronal survival at 25?μm. Methyl, ethyl, propyl, and butyl caffeate esters also significantly enhanced NGF-induced neurite outgrowth, among which the most effective ones were propyl and butyl esters, which at 5?μm led to 25- and 22-fold increases in the number of neurites, respectively. The findings of the docking study suggested phosphatidylinositol 3-kinase (PI3K) as the potential molecular target. In conclusion, our findings demonstrate that alkyl esters of caffeic acid can be useful as scaffolds for the discovery of therapeutic agents for neurodegenerative diseases.
- Hosseini, Razieh,Moosavi, Fatemeh,Rajaian, Hamid,Silva, Tiago,Magalh?es e Silva, Diogo,Soares, Pedro,Saso, Luciano,Edraki, Najmeh,Miri, Ramin,Borges, Fernanda,Firuzi, Omidreza
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p. 926 - 937
(2016/11/11)
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- Palladium-Catalyzed Directed para C?H Functionalization of Phenols
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Various practical methods for the selective C?H functionalization of the ortho and recently also of the meta position of an arene have already been developed. Following our recent development of the directing-group-assisted para C?H functionalization of toluene derivatives, we herein report the first remote para C?H functionalization of phenol derivatives by using a recyclable silicon-containing biphenyl-based template. The effectiveness of this strategy was illustrated with different synthetic elaborations and by the synthesis of various phenol-based natural products.
- Patra, Tuhin,Bag, Sukdev,Kancherla, Rajesh,Mondal, Anirban,Dey, Aniruddha,Pimparkar, Sandeep,Agasti, Soumitra,Modak, Atanu,Maiti, Debabrata
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supporting information
p. 7751 - 7755
(2016/07/07)
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- Coumarin based novel ligands in the Suzuki–Miyaura and Mizoroki–Heck cross-couplings under aqueous medium
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Coumarin-based novel ligands (benzylidine-bis-(4-hydroxycoumarin)-diethylamines) were easily synthesized using 4-hydroxycoumarin, aromatic aldehydes, and diethylamine. The ionic ligand structure was established by X-ray study. They are air and moisture stable ligands and have shown highly efficient catalytic activity with Pd(OAc)2(0.1 mol % loading) in the Suzuki–Miyaura and (0.3 mol % loading) in the Mizoroki–Heck cross-coupling reactions in water or water/ethanol mixture. Pd-catalyst was reused efficiently without affecting variety of functional groups in the reaction.
- Waheed, Mohammed,Ahmed, Naseem
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supporting information
p. 3785 - 3789
(2016/07/26)
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- Functionalized β-cyclodextrin as supramolecular ligand and their Pd(OAc)2 complex: Highly efficient and reusable catalyst for Mizoroki-Heck cross-coupling reactions in aqueous medium
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A novel class of water soluble palladium complexes with recognition abilities based on functionalized β-cyclodextrin has been synthesized. The complex demonstrated high catalytic activity and a supramolecular platform for phosphine-free Mizoroki-Heck cross-coupling reactions in water. The efficient arylation of alkenes was carried out using different iodo- and bromo-arenes with good to excellent yields (up to 96%). The advantages, like recyclability of catalysts, operational simplicity and accessibility in aqueous medium, make this protocol eco-friendly.
- Dindulkar, Someshwar D.,Jeong, Daham,Kim, Hwanhee,Jung, Seunho
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- Catechol-based substrates of chalcone synthase as a scaffold for novel inhibitors of PqsD
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A new strategy for treating Pseudomonas aeruginosa infections could be disrupting the Pseudomonas Quinolone Signal (PQS) quorum sensing (QS) system. The goal is to impair communication among the cells and, hence, reduce the expression of virulence factors and the formation of biofilms. PqsD is an essential enzyme for the synthesis of PQS and shares some features with chalcone synthase (CHS2), an enzyme expressed in Medicago sativa. Both proteins are quite similar concerning the size of the active site, the catalytic residues and the electrostatic surface potential at the entrance of the substrate tunnel. Hence, we evaluated selected substrates of the vegetable enzyme as potential inhibitors of the bacterial protein. This similarity-guided approach led to the identification of a new class of PqsD inhibitors having a catechol structure as an essential feature for activity, a saturated linker with two or more carbons and an ester moiety bearing bulky substituents. The developed compounds showed PqsD inhibition with IC50 values in the single-digit micromolar range. The binding mode of these compounds was investigated by Surface Plasmon Resonance (SPR) experiments revealing that their interaction with the protein is not influenced by the presence of the anthranilic acid bound to active site cysteine. Importantly, some compounds reduced the signal molecule production in cellulo.
- Allegretta, Giuseppe,Weidel, Elisabeth,Empting, Martin,Hartmann, Rolf W.
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p. 351 - 359
(2015/02/19)
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