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Chemistry, Organic (0):
Recent article
Chemistry, Organic
Abstract
The structures of complexes of some small molecules (formaldehyde, acetaldehyde, ammonia, methylamine, methanol, ethanol, acetone, benzene, acetonitrile, ethyl acetate, chloroform, and tetrahydrofuran, considered as possible analytes) with ethylbenzene and silanol (C(6)H(5)C(2)H(5) a...
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PMID: 21080019
PDF is available here.
PDF is available here.
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Bulletin for the history of chemistry / Division of the History ofChemistry of the American Chemical Society (36)1 2011
Abstract
Abstract
The Diels-Alder reaction of vinylboronates can be easily performed using microwave irradiation giving excellent yields of the cycloadducts. Pinacol vinylboronate was the reagent of choice due to its stability towards hydrolysis, operational simplicity and yields of Diels-Alder products. To the best...
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PMID: 20835449
PDF is available here.
PDF is available here.
Abstract
An unexpected discovery of new trans-4-acetyl-1,9-dimethyl-4,4a-dihydro-3H-fluoren-3-ones from one pot reactions of benzaldehydes and acetylacetone is described. The synthetic mechanism and stereochemistry were discussed. These new derivatives exhibit good fluorescent properties in solutions.
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PMID: 20820667
PDF is available here.
PDF is available here.
Abstract
A convergent synthesis of the proposed structure of (+)-pestalazine B has been achieved in 4 steps using the N-alkylation of an unprotected tryptophan diketopiperazine with a 3a-bromopyrrolidinoindoline as the key step. Although its structure was confirmed by X-ray analysis, the spectroscopic data d...
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PMID: 20848034
PDF is available here.
PDF is available here.
Abstract
New multivalent RGD-containing macromolecules were designed by exploiting two orthogonal chemoselective ligations. They were next applied to a competitive cell adhesion assay and used for the non invasive optical imaging of tumour in small animals.
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PMID: 20835451
PDF is available here.
PDF is available here.
Nature Nanotechnology (5)11 2010
Abstract
We report using reconfigurable nucleic acid catalyst-based units to build a multipurpose reprogrammable molecular automaton that goes beyond single-purpose 'hard-wired' molecular automata. The automaton covers all possible responses to two consecutive sets of four inputs (such as four first and four...
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PMID: 20972436
PDF is available here.
PDF is available here.
Nature Nanotechnology (5)11 2010
Abstract
We show that a DNA mechanical device--a DNA walker moving along a DNA track--can be used to perform a series of amine acylation reactions in a single solution without any external intervention. The products of these reactions are programmed by the sequence of the DNA track, but they are not related...
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PMID: 20935654
PDF is available here.
PDF is available here.
Abstract
A new, heterogeneous, 4 A molecular sieve-supported copper(ii) catalyst was developed and was used successfully in the A(3) coupling of alkynes, aldehydes and amines under simple reaction conditions.
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PMID: 20740243
PDF is available here.
PDF is available here.
Optics Express (18)18 2010
Abstract
We observe the appearance of multiple dipole surface plasmon resonances in spherical Ag nanoparticles when embedded in an organic semiconductor that exhibits a highly dispersive permittivity. Comparing the absorption spectra of thin-films with and without Ag nanoparticles reveals the presence of two...
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PMID: 20940797
PDF is available here.
PDF is available here.
Abstract
We have recently described the synthesis of 1alpha,25-dihydroxy-19-norvitamin D3 analogs 2 and 3, possessing an additional ring connecting their 3beta-oxygen and C-2. Such structural constrains prevent the A-ring conformational flexibility and the analogs exist exclusively in the alpha-chair form wi...
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PMID: 20214980
PDF is available here.
PDF is available here.
Abstract
Controlled rainfall experiments utilizing drop-forming rainfall simulators were conducted to study various factors contributing to off-target transport of off-the-shelf formulated pyrethroid insecticides from concrete surfaces. Factors evaluated included active ingredient, product formulation, time...
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PMID: 20524665
PDF is available here.
PDF is available here.
Abstract
Modern chemical synthesis makes heavy use of different types of catalytic systems: homogeneous, heterogeneous and nano-sized. The latter--nano-sized catalysts--have given rise in the 21st century to a rapidly developing area of research encompassing several prospects and opportunities for new techno...
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PMID: 20657394
PDF is available here.
PDF is available here.
Abstract
Nanotechnology (21)20 2010
Abstract
We determine that differences in crystal quality, here quantified as the stacking fault density, are not the primary cause for variations in resistivity of the material studied. The effects of some n-dopant precursors (S, Se, Si, Sn) on InAs nanowire morphology, crystal structure and resistivity wer...
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PMID: 20413840
PDF is available here.
PDF is available here.
Abstract
Abstract
Abstract
The fully automated synthesis of [F]FHBG with Sep-Pak purification was performed within a short synthesis time. The decay-uncorrected radiochemical yield of [F]FHBG was 8-14% (n=10), the radiochemical purity was more than 99%, and the entire synthesis time was less than 40 min. In addition, the PET...
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PMID: 20032804
PDF is available here.
PDF is available here.
Abstract
The synthesis of a new glycomonomer based on mannose, prepared via CuAAC, is reported. The resulting 1,2,3-triazole linkage between mannose and the polymer backbone ensures the formation of highly stable glycopolymers, which will not undergo hydrolysis. The monomer 2'-(4-vinyl-[1,2,3...
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PMID: 19731270
PDF is available here.
PDF is available here.
Abstract
In this paper, a simple and novel synthesis of baicalein is described. This transformation features the novel synthesis of helilandin B and a different way to demethylate. The overall yield of 59% is acceptable.
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PMID: 20390754
PDF is available here.
PDF is available here.
Abstract
An efficient and stereoselective catalytic system for the Heck cross coupling reaction using novel 1,3-dialkyl-3,4,5,6-tetrahydropyrimidinium salts (1, LHX) and Pd(OAc)2 loading has been reported. The palladium complexes derived from the salts 1a-f prepared in situ exhibit good catalytic activity in...
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PMID: 20335935
PDF is available here.
PDF is available here.
Abstract
An overview of the synthesis and applications of chiral 2,3-epoxy alcohols containing unsaturated chains is presented. One of the fundamental synthetic routes to these compounds is Sharpless asymmetric epoxidation, which is reliable, highly chemoselective and enables easy prediction of the product e...
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PMID: 20335961
PDF is available here.
PDF is available here.
Abstract
A sustainable Knoevenagel condensation of a series of aldehydes with malononitrile and ethyl cyanoacetate is described. The process is based on the combination of microwave activation and hydroxyapatite catalysis under solvent-free conditions. Products are obtained in and high yields after short rea...
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PMID: 20335948
PDF is available here.
PDF is available here.
Abstract
We have analyzed them in this minireview. The so-called standard reactions involve "naked" enolates which therefore should lead to the syn adducts as the major products, irrespective of the E, Z stereochemistry of the enolate. Accordingly, provided the second step is rate determining step, the desig...
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PMID: 20335941
PDF is available here.
PDF is available here.
Bulletin for the history of chemistry / Division of the History ofChemistry of the American Chemical Society (35)2 2010
Abstract
Abstract
The author reviews the beginning of the application of the methods of structure elucidation by spectroscopic (metric) techniques at the Department of Organic Chemistry of University of Debrecen and summarizes the most important results obtained in this field between 1992-2009....
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PMID: 21404475
PDF is available here.
PDF is available here.
Abstract
It is expected that the system framework developed in this study would be useful for the in silico design of novel metabolic pathways to be employed for the efficient production of chemicals, fuels and materials....
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PMID: 20346180
PDF is available here.
PDF is available here.
Abstract
The author briefly reviews the beginning of the carbohydrate chemistry in Hungary with special regard to the results achieved at the Department of Organic Chemistry of University of Debrecen and summarizes the most important synthetic and pharmaceutical results obtained in this field between 1992-20...
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PMID: 20443363
PDF is available here.
PDF is available here.
Abstract
A facile synthesis of a series of benzene ring acylated analogues of harmaline has been achieved by Friedel-Crafts acylation under solvent-free conditions at room temperature using acyl halides/acid anhydrides and AlCl3. The reaction afforded 10- and 12-acyl analogues of harmaline in good yield, alo...
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PMID: 20110872
PDF is available here.
PDF is available here.
Abstract
A water-soluble and air-stable Pd(NH3)2Cl2/cationic 2,2'-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu(3)N as a base. The reaction was conducted at 140 degrees C in a sealed tube in air with a catalyst lo...
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PMID: 20110893
PDF is available here.
PDF is available here.
Abstract
We report the synthesis and optical properties of organic porphyrin nanoparticles with narrow size distribution and good dispersibility. Nanoparticles were produced by a combination of precipitation and sonication, termed the "ultrasonic method". The resulting [tetrakis(para-chlorophenyl)porphyrin]T...
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PMID: 20110879
PDF is available here.
PDF is available here.
Abstract
A highly efficient transition-metal-free catalytic system Br2/NaNO2/H2O has been developed for a robust and economic acid-free aerobic oxidation of sulfides. It is noteworthy that the sulfide function reacts under mild conditions without over-oxidation to sulfone. The role of NaNO2as an efficient NO...
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PMID: 20110873
PDF is available here.
PDF is available here.
Abstract
An efficient route for the synthesis of the phosphoramidite derivative of 5-methylcytosine bearing a tert-butylsulfanyl group protected thiol is described. This building block is used for the preparation of oligonucleotides carrying a thiol group at the nucleobase at the internal position of a DNA s...
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PMID: 20720521
PDF is available here.
PDF is available here.
Abstract
A mild and efficient two-step synthesis of 3-substituted beta-carbolinone derivatives from 3-substituted beta-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of beta-carbolin-1-one is proposed. The structures of these compounds were established...
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PMID: 20717074
PDF is available here.
PDF is available here.
Abstract
We describe herein a new, reasonably simple and efficient synthesis of Tyrian purple which opens the way to the production of large quantities of the dye with minimal hazards and at low cost....
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PMID: 20714313
PDF is available here.
PDF is available here.
Abstract
Over the past century, various synthetic approaches have been suggested to the most famous dye of antiquity, Tyrian purple (6,6'-dibromoindigo). These synthetic routes have been exhaustively surveyed and critically evaluated from the perspective of convenience, cost, safety and yield.
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PMID: 20714309
PDF is available here.
PDF is available here.
Abstract
An open-source software package for creating and operating web-based structure and/or reaction databases is presented. Besides standard search capabilities (text, structure/substructure/similarity), the system offers a fast additional search option, entirely based on binary pattern matching, which u...
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PMID: 20714286
PDF is available here.
PDF is available here.
Abstract
The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high...
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PMID: 20714302
PDF is available here.
PDF is available here.
Abstract
We present an overview of recent advances in protecting groups influencing stereoselectivity in glycosylation reactions, including participating protecting groups, and conformation-constraining protecting groups in general....
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PMID: 20966873
PDF is available here.
PDF is available here.
Abstract
We report a novel method for the synthesis of fractal Zn structures through a solution phase reaction. An Al-film-deposited substrate was immersed in an aqueous ammonia solution containing Zn ions and maintained at 95 degrees C for 5 min. After the reaction, the Al-deposited side of the substrate wa...
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PMID: 19453111
PDF is available here.
PDF is available here.
Abstract
Our computational results demonstrate the plausibility that the well-known [3 + 2] cycloaddition of transition metal oxides to alkenes in organic chemistry can be employed as a new type of surface reaction to functionalize the semiconductor X (100) surface, which offers the new possibility for self-...
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PMID: 19499936
PDF is available here.
PDF is available here.
Natural Product Reports (26)9 2009
Abstract
Abstract
A new method for attaining higher stability of thermolabile protecting groups (TPG) using an intramolecular cyclization through a "click-clack" approach was demonstrated. It was found that during intramolecular cyclization of 2-pyridyl type of TPG the thermally stable 3-pyridyl-[1,3,2]oxazaphospholi...
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PMID: 19719206
PDF is available here.
PDF is available here.
Abstract
The hydroxyl radical (HO*) is a strong oxidant that reacts with electron-rich sites of organic compounds and initiates complex chain mechanisms. In order to help understand the reaction mechanisms, a rule-based model was previously developed to predict the reaction pathways. For a kinetic model, the...
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PMID: 19746717
PDF is available here.
PDF is available here.
Audio, Transactions of the IRE Professional Group on (Chapter 16) 2009
Abstract
We have shown that such base-modified units introduced into functionally important sites of siRNA modulate thermodynamic stability of the duplex and its gene silencing activity. In this unit, we describe chemical synthesis of 3'-phosphoramidite derivatives of s(2)U and D units (the 3'-phosphoramidit...
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PMID: 19488969
PDF is available here.
PDF is available here.
Abstract
The formation of carbon-halogen bonds in an enantioselective manner is an important reaction because it leads to optically active halogen compounds, which are useful intermediates for further elaboration to other valuable compounds. Within the past few years various enantioselective alpha-halogenati...
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PMID: 19421434
PDF is available here.
PDF is available here.
Abstract
Solid phase microextraction (SPME) is applied in the dynamic speciation analysis of the pesticide atrazine in an aqueous medium containing sorbing latex nanoparticles. It is found that the overall rate of extraction of the analyte is faster than in the absence of nanoparticles and governed by the co...
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PMID: 19708138
PDF is available here.
PDF is available here.
Abstract
We present an alternative means of functionalizing carbon substrates based on Grignard chemistry. First, the amorphous carbon substrates are halogenated with a solution-based, radical-initiated halogenation reaction using PX5 (X = Br or Cl). Next, the halogenated surfaces are modified via the format...
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PMID: 19708232
PDF is available here.
PDF is available here.
Abstract
This review tracks a decade of dynamic kinetic resolution developments with a biocatalytic inclination using enzymatic/microbial means for the resolution part followed by the racemization reactions either by means of enzymatic or chemocatalyst. These fast developments are due to the ability of the b...
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PMID: 18655180
PDF is available here.
PDF is available here.
Abstract
Various new chiral hydroxysulfonamide ligands (3a-3n, 4a-4d) were prepared. Compounds 3a, 3g, 3i, 3k-3n, 4a-4d could accelerate the reaction and reduce reaction time, and 3a, 3g, 3i, 3k-3n catalyzed the reaction without titanium. The results obtained were promising in terms of yields and enantiomeri...
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PMID: 18655167
PDF is available here.
PDF is available here.
Abstract
A chiral selector was prepared through the reaction between (1S,2R)-(+)-2-amino-1,2-diphenylethanol and phenyl isocyanate. This selector was immobilized on aminated silica gel, respectively, with bifunctional group linkers of 1,4-phenylene diisocyanate, methylene-di-p-phenyl diisocyanate, and tereph...
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PMID: 18655165
PDF is available here.
PDF is available here.
Abstract
A series of silica-supported proline-based peptides were synthesized and applied as catalysts for direct asymmetric intermolecular aldol reactions. Among these, a peptide with two L-proline units was found to be the most efficient one for the asymmetric aldol reactions between acetone and aromatic a...
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PMID: 18570310
PDF is available here.
PDF is available here.
Abstract
The design of substituted lactols is described, which in their reaction with racemic alkyl aryl carbinols react preferentially with one of the enantiomers exhibiting selectivities up to 14:1.
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PMID: 18655172
PDF is available here.
PDF is available here.
Revue d histoire de la pharmacie (57)361 2009
Abstract
At the end of the 19th century, Auguste Béhal, student of Wurtz and Friedel, imposes the atomic theory, in the French higher education. Béhal then will teach and direct the work of many students called Béhaliens. Among the latter, one finds Amand Valeur and Raymond Delaby which are originating in...
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PMID: 19824346
PDF is available here.
PDF is available here.
Nano Letters (9)3 2009
Abstract
We report a general approach for fully spray-coated organic photodiodes with outstanding characteristics in comparison to bladed or spin-coated devices. Despite the high surface roughness and the less defined morphology of the spray-deposited organic layers, we observe organic photodetectors with re...
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PMID: 19239203
PDF is available here.
PDF is available here.
Abstract
A combined supercritical and subcritical process for pretreatment and hydrolysis of lignocellulosic waste has been proposed. Batch experiments and kinetic analysis were performed to investigate the secondary hydrolysis of cellulose in subcritical water as well as the feasibility of combining the who...
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PMID: 19350936
PDF is available here.
PDF is available here.
Abstract
Serious (up to 87 kJ mol(-1)) systematic DFT errors in a series of isodesmic reactions are found to be due to the DFT exchange component, and can be largely corrected by substitution of the DFT exchange energy with the Fock exchange energy.
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PMID: 19209354
PDF is available here.
PDF is available here.
Abstract
A novel linker system based on 3-aminoxypropionate was designed and evaluated for drug release using proteolysis as an activation trigger followed by intramolecular cyclization. The hydroxylamine moiety present in the linker system enabled faster release of the parent drug from the linker-drug conju...
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PMID: 19097896
PDF is available here.
PDF is available here.
Abstract