- (NO)Ru(salen)-Catalyzed Aerobic Oxidation of o-Hydroxybenzyl Alcohol Derivatives
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Various salicylaldehyde derivatives were prepared from the corresponding alcohols in good to excellent yields by ecologically benign aerobic oxidation using ruthenium salen nitrosyl complex 1 as catalyst under visible light-irradiation.
- Tashiro, Aya,Mitsuishi, Akimasa,Irie, Ryo,Katsuki, Tsutomu
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- Activated Self-Resolution and Error-Correction in Catalytic Reaction Networks**
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Understanding the emergence of function in complex reaction networks is a primary goal of systems chemistry and origin-of-life studies. Especially challenging is to create systems that simultaneously exhibit several emergent functions that can be independently tuned. In this work, a multifunctional complex reaction network of nucleophilic small molecule catalysts for the Morita-Baylis-Hillman (MBH) reaction is demonstrated. The dynamic system exhibited triggered self-resolution, preferentially amplifying a specific catalyst/product set out of a many potential alternatives. By utilizing selective reversibility of the products of the reaction set, systemic thermodynamically driven error-correction could also be introduced. To achieve this, a dynamic covalent MBH reaction based on adducts with internal H-transfer capabilities was developed. By careful tuning of the substituents, rate accelerations of retro-MBH reactions of up to four orders of magnitude could be obtained. This study thus demonstrates how efficient self-sorting of catalytic systems can be achieved through an interplay of several complex emergent functionalities.
- Schaufelberger, Fredrik,Ramstr?m, Olof
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supporting information
p. 10335 - 10340
(2021/05/07)
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- Imine or Enamine? Insights and Predictive Guidelines from the Electronic Effect of Substituents in H-Bonded Salicylimines
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Imine and enamine bonds decorate the skeleton of numerous reagents, catalysts, and organic materials. However, it is difficult to isolate at will a single tautomer, as dynamic equilibria occur easily, even in the solid state, and are sensitive to electronic and steric effect, including π-conjugation and H-bonding. Here, using as model Schiff bases generated from salicylaldehydes and TRIS in a set of linear free energy relationships (LFER), we disclose how the formation of either imines or enamines can be controlled and provide a comprehensive framework that captures the structural underpinning of this prediction. This work highlights the potentiality of tailor-made designs en route to compounds with desirable functionality.
- Cintas, Pedro,Martínez, R. Fernando,Matamoros, Esther,Palacios, Juan C.
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p. 5838 - 5862
(2020/05/20)
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- Intramolecular Povarov Reactions for the Synthesis of Chromenopyridine Fused 2-Pyridone Polyheterocycles Binding to α-Synuclein and Amyloid-β Fibrils
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A BF3·OEt2 catalyzed intramolecular Povarov reaction was used to synthesize 15 chromenopyridine fused thiazolino-2-pyridone peptidomimetics. The reaction works with several O-alkylated salicylaldehydes and amino functionalized thiazolino-2-pyridones, to generate polyheterocycles with diverse substitution. The synthesized compounds were screened for their ability to bind α-synuclein and amyloid β fibrils in vitro. Analogues substituted with a nitro group bind to mature amyloid fibrils, and the activity moreover depends on the positioning of this functional group.
- Adolfsson, Dan E.,Tyagi, Mohit,Singh, Pardeep,Deuschmann, Adrian,?dén, J?rgen,Gharibyan, Anna L.,Jayaweera, Sanduni Wasana,Lindgren, Anders E. G.,Olofsson, Anders,Almqvist, Fredrik
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p. 14174 - 14189
(2020/11/13)
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- Catalytic oxidation of alcohols and alkyl benzenes to carbonyls using Fe3O4?SiO2?(TEMPO)-: Co -(Chlorophyll-CoIII) as a bi-functional, self-co-oxidant nanocatalyst
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Chlorophyll b was extracted from heliotropium europaeum plant, demetalated, allylated and grafted to acrylated TEMPO through a copolymerization protocol. Then, the chlorophyll monomers were coordinated to Co ions, immobilized on magnetic nanoparticles and the resulting hybrid was used as a powerful catalyst for a variety of oxidation reactions. By using the present method, oxidation of benzylic alcohols and alkyl benzenes to carbonyls was accomplished in water under aerobic conditions. Moreover, direct oxidation of alcohols to carboxylic acids was performed by adding NaOCl to the mixture. All entries were oxidized to the corresponding desired product with high to excellent yields and up to 97% selectivity. The catalyst was thoroughly characterized by CV, TGA, VSM, XRD, XPS, DLS, FE-SEM, TEM, UV-Vis, EDX, and BET analyses. The activity of the catalyst was investigated by applying various components of the catalyst to the oxidation model separately. The reasonable mechanisms are suggested based on the cooperation between the TEMPO groups and cobalt(iii) (or Co(iv)) sites on the catalyst. The catalyst could be recovered and reused for at least 7 consecutive recycles without any considerable reactivity loss. This journal is
- Hamah-Ameen, Baram Ahmed,Kazemnejadi, Milad,Mahmoudi, Boshra,Rostami, Amin
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p. 6600 - 6613
(2020/11/16)
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- Fast-response formaldehyde fluorescent probe as well as preparation method and application thereof
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The invention relates to a fast-response formaldehyde fluorescent probe as well as a preparation method and application thereof, and belongs to the technical field of fast formaldehyde detection. Theprobe uses coumarin as a matrix; diazanyl is used as a reaction group to react with formaldehyde; the fast detection on the formaldehyde is realized through the fluorescent change of the probe. The response time of the formaldehyde is as low as 220 s; the fluorescence intensity at 503 nm is obviously enhanced. The fast and nondestructive detection on the formaldehyde in a water solution is realized by the probe; the detection lower limit of the formaldehyde is 5*10 mol/L. The probe can resist the interference of cysteine, glutathione, L-arginine, sodium citrate, homocysteine, phenylalanine, alanine, glutamic acid, glycine, methionine, sodium ascorbate, Ca, Na, Mg, K and hydrogen peroxide; the selective specificity is high. The probe is applied to the fast detection on thecontent of the formaldehyde in food and textiles; various indexes are excellent; the fast detection requirements are completely met. The probe can also detect the formaldehyde in living cells througha confocal fluorescence microscope, and the fluorescence imaging is performed.
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- Fe3O4@SiO2@Im[Cl]Mn(III)-complex as a highly efficient magnetically recoverable nanocatalyst for selective oxidation of alcohol to imine and oxime
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An efficient and environmentally friendly oxidation process for the one-pot preparation of oxime, imine and carbonyl compounds through alcohol oxidation in the presence of H2O2 and/or O2 have been developed by a melamine-Mn(III) Schiff base complex supported on Fe3O4@SiO2–Cl nanoparticles, named as Fe3O4@SiO2@Im[Cl]Mn(III)-complex nanocomposite, at room temperature. Direct oxidation of alcohol to carboxylic acid was performed using the catalyst in the presence of molecular O2 at room temperature in a different approach. The oxidation products were obtained with excellent yields and high TOFs. The properties of the catalyst were characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis (C, H, N), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), inductive coupled plasma (ICP), cyclic voltammetry (CV), nuclear magnetic resonance (1H & 13C NMR), vibration sample magnetometer (VSM), Brunauer– Emmett–Teller (BET) and differential pulse voltammetry (DPV) analyses. The mechanism of the oxidation processes was investigated for the both H2O2 and O2 oxidants. The role of the imidazolium moiety in the catalyst as a secondary functionality was investigated. Chemoselectivity behavior of the catalyst was studied by some combinations. The catalyst could be recycled from the reaction mixture by a simple external magnet and reused for several times without any considerable reactivity loss.
- Kazemnejadi, Milad,Alavi, Seyyedeh Ameneh,Rezazadeh, Zinat,Nasseri, Mohammad Ali,Allahresani, Ali,Esmaeilpour, Mohsen
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p. 230 - 249
(2019/03/28)
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- Deciphering the Mechanism of Human Carbonic Anhydrases Inhibition with Sulfocoumarins: Computational and Experimental Studies
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The reaction mechanism of the carbonic anhydrase-mediated hydrolysis of sulfocoumarins to sulfonic acids has been investigated on an enzyme cluster model using the B3LYP hybrid density functional theory (DFT) and the QST procedure for the Transition State (TS) search. A multistep process was highlighted, with the rate-determining step identified in the initial dual nucleophilic/acidic attack of the zinc-bound hydroxide ion to the sulfocoumarin sulfur atom and to the C3=C4 double bond. The reported multi-step process, combined to SAR analysis on a new set of derivatives, highlighted unprecedented mechanistic aspects of the CA-mediated prodrug activation, which in turn possess relevant consequences to the isoforms-selective inhibition profiles reported by such a class of compounds.
- Nocentini, Alessio,Carta, Fabrizio,Tanc, Muhammet,Selleri, Silvia,Supuran, Claudiu T.,Bazzicalupi, Carla,Gratteri, Paola
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supporting information
p. 7840 - 7844
(2018/05/08)
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- N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) as a green and reusable heterogeneous nanocatalyst for the chemoselective preparation and deprotection of acylals
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Abstract: N-propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was simply synthesized and used as a highly efficient, environmentally friendly, and chemoselective catalyst for the synthesis of 1,1-diacetates (acylals) from the one-pot condensation reaction of various aromatic aldehydes with acetic anhydride, in high yield of products (86–96%) and short reaction time (20–60?min) under solvent-free conditions at room temperature. In addition to these results, we further studied the possibility of deprotection of the resulting acylals into benzaldehyde derivatives in this catalytic system by the addition of water. More importantly, noteworthy advantages of this study are non-use of toxic organic solvents and catalysts, simple work-up procedure, short reaction time, high yield of products, and recovery and reusability of MNPs-PSA by an external magnet. Graphical Abstract: A simple and highly efficient procedure for the protection of various aldehydes with acetic anhydride in the presence of N-propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) is reported. We further studied the possibility of deprotection of the resulting acylals into benzaldehyde derivatives in this catalytic system by the addition of water as a green solvent. The catalyst was reused several times without loss of its catalytic activity.
- Sajjadifar, Sami,Nasri, Parastoo
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p. 6677 - 6689
(2017/10/06)
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- 3. 4 - diphenyl - 4H - 1, 2, 4 - triazole derivative and its preparation method and application (by machine translation)
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The invention discloses 3, 4 - diphenyl - 4H - 1, 2, 4 - triazole derivative and its preparation method and application. In particular, the invention relates to the formula (I) structure of 3, 4 - diphenyl - 4H - 1, 2, 4 - triazole derivatives, its stereoisomers or its pharmaceutically acceptable salt, formula (I) in the definition of each substituent is as defined in the specification. These structure of novel compound with heat shock protein HSP90 inhibitory activity, can be used for treating cancer, neurodegenerative diseases, inflammatory diseases, autoimmune diseases, ischemic brain injury and the like, it has broad application prospects. (by machine translation)
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- Pyrimidine heterocyclic compounds, pyrimidine heterocyclic compound salts, and preparation method and application thereof
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The invention provides pyrimidine heterocyclic compounds, pyrimidine heterocyclic compound salts, and a preparation method and application thereof. According to the pyrimidine heterocyclic compounds provided by the invention, specific Rq is selected, so that the obtained compounds have favorable drug resistance and long half life when being used as the medicine for treating or preventing HIV. The compounds have the advantages of high activity, low toxicity and high stability.
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- Direct preparation of oximes and Schiff bases by oxidation of primary benzylic or allylic alcohols in the presence of primary amines using Mn(III) complex of polysalicylaldehyde as an efficient and selective heterogeneous catalyst by molecular oxygen
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The present work introduced the new strategy for direct preparation of Schiff base as well as oxime compounds through oxidation of primary benzylic or allylic alcohols in the presence of amines by complexation of Mn(III) to a polymeric Schiff base ligand based on polysalicylaldehyde (PSA-Schiff base-Mn(III) complex). As a new environmentally benign protocol, manganese heterogeneous polymeric catalytic system demonstrated promising oxidation of alcohols in ethanol using molecular oxygen. PSA was synthesized through polycondensation reaction of 2-hydroxy-5-chloromethyl-benzaldehyde and then treated with 2-aminophenol to form polymeric ligand. Average molecular weight of PSA was studied by an analytical method as well as GPC analysis. Formation of the catalyst was characterized step by step by FTIR, UV–Vis, 1H NMR, TGA, CHN and EDX analyses. Loading amounts of metal ions as well as leaching amount of the catalysis were studied by ICP-OES instrument. The catalyst shows up to high yields for oxidation of primary and secondary primary benzylic or allylic alcohols to carbonyl compounds, especially direct imine formation in a mild, inexpensive and efficient method which can be successfully recovered from the reaction mixture and reused for several times without any remarkable reactivity loss. Effect of solvent, temperature, catalyst amount and oxygen donors along with some blank experiments to elucidation of catalyst activity was evaluated in this work. Also chemoselectivity behavior of the catalyst was investigated with some combinations.
- Kazemnejadi, Milad,Shakeri, Alireza,Mohammadi, Mohammad,Tabefam, Marzieh
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p. 1917 - 1933
(2017/08/15)
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- A convenient approach to an advanced intermediate toward the naturally occurring, bioactive 6-substituted 5-hydroxy-4-aryl-1H-quinolin-2-ones
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5-Hydroxy-4-aryl-3,4-dihydro-1H-quinolin-2-ones are a small family of natural products isolated from fungal strains of Penicillium and Aspergillus. Most of its members, which are insecticides and anthelmintics, carry an isoprenoid C-6 side chain. The synthesis of a 6-propenyl-substituted advanced intermediate for the total synthesis of these natural products is presented in this paper. This was achieved through the stereoselective construction of a β,β-diarylacrylate derivative from 6-nitrosalicylaldehyde, using a Wittig olefination and a Heck-Matsuda arylation, followed by a selective Fe0-mediated reductive cyclization. Installation of the 6-propenyl side chain was performed by 5-O-allylation of the heterocycle, followed by Claisen rearrangement and conjugative migration of the allyl double bond, as the key steps. The Grubbs II-catalyzed olefin cross metathesis of the 6-allyl moiety with 2-methylbut-2-ene to afford a precursor of peniprequinolone is also reported.
- Simonetti, Sebastián O.,Larghi, Enrique L.,Kaufman, Teodoro S.
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p. 2625 - 2636
(2016/03/05)
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- Copper-Catalyzed Preparation of 2-Aryl-3-cyanobenzofurans with Bright Blue Photoluminescence
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Copper-catalyzed cascade synthesis of 2-aryl-3-cyanobenzofurans from o-hydroxybenzaldehydes and arylacetonitriles in the presence of copper acetate and sodium methoxide is reported. The synthesized 2-aryl-3-cyanobenzofurans emit bright blue under UV light with a quantum yield up to 88.9%. (Chemical Equation Presented).
- Zhang, Lianpeng,Peng, Zhixing,Wen, Qiaodong,Li, Xihui,Lu, Ping,Wang, Yanguang
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p. 728 - 731
(2016/03/01)
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- Discovery of BI 207524, an indole diamide NS5B thumb pocket 1 inhibitor with improved potency for the potential treatment of chronic hepatitis C virus infection
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The development of interferon-free regimens for the treatment of chronic HCV infection constitutes a preferred option that is expected in the future to provide patients with improved efficacy, better tolerability, and reduced risk for emergence of drug-resistant virus. We have pursued non-nucleoside NS5B polymerase allosteric inhibitors as combination partners with other direct acting antivirals (DAAs) having a complementary mechanism of action. Herein, we describe the discovery of a potent follow-up compound (BI 207524, 27) to the first thumb pocket 1 NS5B inhibitor to demonstrate antiviral activity in genotype 1 HCV infected patients, BILB 1941 (1). Cell-based replicon potency was significantly improved through electronic modulation of the pKa of the carboxylic acid function of the lead molecule. Subsequent ADME-PK optimization lead to 27, a predicted low clearance compound in man. The preclinical profile of inhibitor 27 is discussed, as well as the identification of a genotoxic metabolite that led to the discontinuation of the development of this compound.
- Beaulieu, Pierre L.,Anderson, Paul C.,Bethell, Richard,B?s, Michael,Bousquet, Yves,Brochu, Christian,Cordingley, Michael G.,Fazal, Gulrez,Garneau, Michel,Gillard, James R.,Kawai, Stephen,Marquis, Martin,McKercher, Ginette,Poupart, Marc-André,Stammers, Timothy,Thavonekham, Bounkham,Wernic, Dominik,Duan, Jianmin,Kukolj, George
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p. 10130 - 10143
(2015/02/05)
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- Development of luciferin analogues bearing an amino group and their application as BRET donors
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We systematically synthesized bioluminogenic substrates bearing an amino group on benzothiazole, quinoline, naphthalene, and coumarin scaffolds. They emit bioluminescence in various colors: red, orange, yellow, and green. An amino-substituted cou-marylluciferin derivative, coumarylami-noluciferin (CAL), showed the shortest bioluminescence wavelength among substrates reported so far. Further, the fluorescence of CAL did not exhibit solvatochromism, which suggests that its bioluminescence is not susceptible to environmental factors. We applied CAL as an energy-donor substrate for a bioluminescence resonance energy transfer (BRET) system with click beetle red luciferase (CBRluc), a mutant of firefly luciferase, as the energy-donor enzyme and yellow fluorescent protein (YFP) as the energy-acceptor fluorophore, and obtained a clearly bimodal bioluminescence spectrum. Stable bioluminescence that is not influenced by environmental factors is highly desirable for reliable measurements in biological assays.
- Takakura, Hideo,Sasakura, Kiyoshi,Ueno, Tasuku,Urano, Yasuteru,Terai, Takuya,Hanaoka, Kenjiro,Tsuboi, Takashi,Nagano, Tetsuo
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experimental part
p. 2053 - 2061
(2011/04/23)
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- Kinetic characterization of spiropyrans in aqueous media
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Detailed kinetic investigations of the most common photoswitchable spiropyran, 6-nitro-BIPS, reveal that hydrolytic decomposition of its merocyanine isomer limits its utility in aqueous buffer; however, simple replacement of the 6-nitro substituent with a
- Stafforst, Thorsten,Hilvert, Donald
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scheme or table
p. 287 - 288
(2009/05/06)
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- Total synthesis and evaluation of iso-duocarmycin SA and iso-yatakemycin
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The total synthesis and evaluation of iso-duocarmycin SA (5) and iso-yatakemycin (6), representing key analogues of the corresponding natural products incorporating an isomeric alkylation subunit, are detailed. This pyrrole isomer of the natural alkylation subunit displayed an enhanced reaction regioselectivity and a 2-fold diminished stability. Although still exceptionally potent, the /so-duocarmycin SA derivatives and natural product analogues exhibited a corresponding approximate 3-5-fold reduction in cytotoxic activity [L1210 IC50 for (+)-iso-duocarmycin SA = 50 pM and for (+)-/so-yatakemycin = 15 pM] consistent with their placement on a parabolic relationship correlating activity with reactivity. The DNA alkylation selectivity of the resulting key natural product analogues was unaltered by the structure modification in spite of the minor-groove presentation of a potential H-bond donor. Additionally, a unique ortho-spirocyclization with such derivatives was explored via the preparation, characterization, and evaluation of 34 that is incapable of themore conventional para-spirocyclization. Although 34 proved sufficientl y stable for isolation and characterization, it displayed little stability in protic solvents (f1/2 = 0.19hatpH3, t 1/2 = 0.20 h at pH 7), a pH-independent (H+ independent) solvolysisrate profile at pH 3/4-7, and a much reduced cytotoxic potency, but a D NA alkylation selectivity and efficiency comparable to those of duocarmycin SA and iso-duocarmycin SA. The implications of these observations onthe source of the DNA alkylation selectivity and catalysis for this cla ss of natural products are discussed.
- MacMillan, Karen S.,Nguyen, Trihn,Hwang, Inkyu,Boger, Dale L.
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supporting information; experimental part
p. 1187 - 1194
(2009/06/28)
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- Discovery of inhibitors of aberrant gene transcription from libraries ofdna binding molecules: Inhibition of LEF-1-mediated gene transcription and oncogenic transformation
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The screening of a >9000 compound library of synthetic DNA binding molecules for selective binding to the consensus sequence of the transcription factor LEF-1 followed by assessment of the candidate compounds in a series of assays that characterized functional activity (disruption of DNA-LEF-1 binding) at the intended target and site (inhibition of intracellular LEF-1-mediated gene transcription) resulting in a desired phenotypic cellular change (inhibit LEF-1-driven cell transformation) provided two lead compounds: lefmycin-1 and lefmycin-2. The sequence of screens defining the approach assures that activity in the final functional assay may be directly related to the inhibition of gene transcription and DNA binding properties of the identified molecules. Central to the implementation of this generalized approach to the discovery of DNA binding small molecule inhibitors of gene transcription was (1) the use of a technically nondemanding fluorescent intercalator displacement (FID) assay for initial assessment of the DNA binding affinity and selectivity of a library of compounds for any sequence of interest, and (2) the technology usedto prepare a sufficiently large library of DNA binding compounds.
- Stover, James S.,Shi, Jin,Jin, Wei,Vogt, Peter K.,Boger, Dale L.
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supporting information; experimental part
p. 3342 - 3348
(2009/07/30)
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- [Ce(NO3)3]3-H2IO6: Efficient oxidation reactions under solvent-free conditions
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Efficient solvent-free oxidation of alcohols, deprotection and oxidative deprotection of trimethylsilyl ethers and oxidative deprotection of oximes using tris [trinitratocerium (IV)] paraperiodate (TTCPP) is reported.
- Shirini,Esm-Hosseini,Hejazi,Mohammadpoor-Baltork
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- VIRAL POLYMERASE INHIBITORS
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A compound, represented by formula (I) or an enantiomer, diastereoisomer or tautomer thereof : wherein either A or B is nitrogen and the other B or A is C, and the radicals R1, R2, R3, R5, R6, R7, R9, and R10 are as defined herein, or a salt, ester or derivative thereof as viral polymerase inhibitors. The compound is used as an inhibitor of RNA dependent RNA polymerases, particulary those viral polymerases within the Flaviviridae family, more particulary to HCV polymerase.
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Page/Page column 50
(2010/02/15)
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- BENZOTHIOPHENE UREA, BENZOFURANE UREA, AND INDOLE UREA, AND USE OF THE SAME AS ALPHA-7 ACHR AGONISTS
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The invention relates to novel benzothiophene urea, benzofurane urea, and indole urea, and to the use thereof for producing medicaments for the treatment and/or prophylaxis of diseases and for improving perception, concentration power, learning capacity and/or memory retention.
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Page/Page column 46
(2010/11/30)
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- Selective nitration of aromatic compounds with bismuth subnitrate and thionyl chloride
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Bismuth subnitrate/thionyl chloride have been found to be an efficient combination of reagents for nitration of a wide range of aromatic compounds in dichloromethane. Phenols, in particular, were easily mononitrated and dinitrated with the reagents by controlling the stoichiometry.
- Muathen, Hussni A.
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p. 593 - 598
(2007/10/03)
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- Vanilloid receptor ligands and their use in treatments
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Compounds having the general structure and compositions containing them, for the treatment of acute, inflammatory and neuropathic pain, dental pain, general headache, migraine, cluster headache, mixed-vascular and non-vascular syndromes, tension headache, general inflammation, arthritis, rheumatic diseases, osteoarthritis, inflammatory bowel disorders, inflammatory eye disorders, inflammatory or unstable bladder disorders, psoriasis, skin complaints with inflammatory components, chronic inflammatory conditions, inflammatory pain and associated hyperalgesia and allodynia, neuropathic pain and associated hyperalgesia and allodynia, diabetic neuropathy pain, causalgia, sympathetically maintained pain, deafferentation syndromes, asthma, epithelial tissue damage or dysfunction, herpes simplex, disturbances of visceral motility at respiratory, genitourinary, gastrointestinal or vascular regions, wounds, burns, allergic skin reactions, pruritis, vitiligo, general gastrointestinal disorders, gastric ulceration, duodenal ulcers, diarrhea, gastric lesions induced by necrotising agents, hair growth, vasomotor or allergic rhinitis, bronchial disorders or bladder disorders.
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- Vicarious nucleophilic substitution of hydrogen in nitrophenyl toluenesulfonates
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Toluenesulfonates of nitrophenols react with carbanions possessing leaving groups giving products of the vicarious nucleophilic substitution of hydrogen. The yields and orientation depend on the reaction conditions and the structure of the reagents. The products obtained can be easily hydrolyxed to the corresponding phenols or - in certain cases - to hydroxynitrobenzaldehydes.
- Makosza, Mieczyslaw,Ziobrowski, Tadeusz,Serebriakov, Mikhail,Kwast, Andrzej
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p. 4739 - 4750
(2007/10/03)
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- CONVENIENT SYNTHESIS OF A SIMPLE COUMARIN FROM SALICYLALDEHYDE AND WITTIG REAGENT (III): SYNTHESIS OF NITROCOUMARINS
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Reaction of nitrosalicylaldehydes (1) with carbethoxymethylenetriphenylphosphorane in Et2NPh, in Ph2O, and in the absence of solvent (neat) at 210-215 deg C was investigated.Reaction of 3-nitrosalicylaldehyde (1d) in Et2NPh afforded the benzoxazole (6) and the aminocoumarin (3e) along with the expected coumarin (3d).It was clarified that the origin of carbon-unit introduced for the formation of the benzoxazole ring came from the alkyl group of solvent.
- Harayama, Takashi,Nakatsuka, Kazumitsu,Nishioka, Hiromi,Maurakami, Kyoko,Ohmori, Yukiko,et al.
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p. 2729 - 2738
(2007/10/02)
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