Bibliografías temáticas / Versatile intermediates

Literatura académica sobre el tema "Versatile intermediates"

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Publicado: 6 de septiembre de 2023

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Artículos de revistas sobre el tema "Versatile intermediates"

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Boeske, Juergen, Edgar Niecke, Edgar Ocando-Mavarez, Jean Pierre Majoral y Guy Bertrand. "Phosphonitriles: versatile intermediates". Inorganic Chemistry 25, n.º 16 (julio de 1986): 2695–98. http://dx.doi.org/10.1021/ic00236a008.

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Belletire, J. L. "Acylcyanamides: Versatile Synthetic Intermediates". Synthetic Communications 18, n.º 16-17 (noviembre de 1988): 2063–71. http://dx.doi.org/10.1080/00397918808068275.

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R. Katritzky, Alan, Adam S. Vincek y Peter J. Steel. "Triphenylphosphoranylidene Substituted Heterocycles as Versatile Intermediates". HETEROCYCLES 76, n.º 2 (2008): 1401. http://dx.doi.org/10.3987/com-08-s(f)12.

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Britten, Thomas K., Paul D. Kemmitt, Nathan R. Halcovitch y Susannah C. Coote. "1,2-Dihydropyridazines as Versatile Synthetic Intermediates". Synlett 31, n.º 05 (13 de febrero de 2020): 459–62. http://dx.doi.org/10.1055/s-0039-1690825.

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The reactivity of 1,2-dihydropyridazines under various conditions is described, leading to the formation of a variety of products, including 2-aminopyrroles, phenylenediamines, and several novel heterocyclic motifs.
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Bari, Ahmed. "Monosaccharidic Push-pull Butadienes: Versatile Synthetic Intermediates". Zeitschrift für Naturforschung B 69, n.º 1 (1 de enero de 2014): 98–102. http://dx.doi.org/10.5560/znb.2014-3179.

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Monosaccharidic push-pull butadienes are interesting building blocks for the synthesis of various heterocyclic and natural products due to their biological prevalence and significant p-electron interactions between donor and acceptor groups. A series of 1,5-anhydro-3,4,6-tri-O-benzyl-2-deoxy- 2-formyl-D-arabino-hex-1-enitol (2) and 1,5-anhydro-3,4-di-O-benzyl-2-deoxy-2-formyl-L-erythrohex- 1-enitol (4) derived push-pull branched chain sugars have been synthesized by condensation with active methylene compounds using basic aluminum oxide (Al2O3) or anhydrous sodium acetate (NaOAc) at room temperature. The compounds have been fully characterized by spectroscopic techniques and elemental analyses.
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Attanasi, Orazio A. y Luciano Caglioti. "CONJUGATED AZOALKENES: ATTRACTIVE PRODUCTS AND VERSATILE INTERMEDIATES". Organic Preparations and Procedures International 18, n.º 5 (octubre de 1986): 299–327. http://dx.doi.org/10.1080/00304948609356836.

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Flashman, Emily y Christopher J. Schofield. "The most versatile of all reactive intermediates?" Nature Chemical Biology 3, n.º 2 (febrero de 2007): 86–87. http://dx.doi.org/10.1038/nchembio0207-86.

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Zellner, Armin y Manfred Schlosser. "Pentadienyltitaniums as Versatile Intermediates: Regio- and Stereoselectivities". Synlett 2001, Special Issue (2001): 1016–18. http://dx.doi.org/10.1055/s-2001-14650.

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Barrett, Anthony G. M. y Gregory G. Graboski. "Conjugated nitroalkenes: versatile intermediates in organic synthesis". Chemical Reviews 86, n.º 5 (octubre de 1986): 751–62. http://dx.doi.org/10.1021/cr00075a002.

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Michael, J. P., C. B. de Koning, D. Gravestock, G. D. Hosken, A. S. Howard, C. M. Jungmann, R. W. M. Krause, A. S. Parsons, S. C. Pelly y T. V. Stanbury. "Enaminones: versatile intermediates for natural product synthesis". Pure and Applied Chemistry 71, n.º 6 (30 de junio de 1999): 979–88. http://dx.doi.org/10.1351/pac199971060979.

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Tesis sobre el tema "Versatile intermediates"

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Vincent-Rocan, Jean-François. "N-Isocyanates : Versatile Intermediates in Heterocyclic Synthesis". Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34864.

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Nitrogen heterocycles are present in nearly 60% of all small-molecule drugs approved by the US Food and Drug Administration. New innovative methods that streamline the synthesis of such heterocycles are therefore highly desirable. The use of new or underdeveloped reactive intermediates provides an excellent opportunity to develop novel heterocyclic syntheses. For example, nitrogen-substituted isocyanates (N-isocyanates) are a class of rare amphoteric isocyanates with high, but severely underdeveloped synthetic potential. The research efforts presented in this thesis have been directed towards the use of such intermediates for the rapid construction of heterocycles using cascade reactions. Using an in situ generation approach from masked (blocked) isocyanate precursors, we were able to control the homo dimerization of these species and design several cascade reactions forming more than 10 different classes of heterocycles using appropriate nitrogen nucleophiles. Given the importance of the N-N-C=O motif in pharmaceuticals and agrochemicals, N-isocyanates provide the opportunity to synthesize highly desirable cores for different industrial applications. To illustrate the potential of this new tool in heterocyclic chemistry, more than 200 heterocycles were synthesized using this methodology. In Chapter 2, heterocycles incorporating only one atom from the N-isocyanate will be presented. More precisely, the first cascade reaction involving N-isocyanates for the rapid synthesis of saturated heterocycles will be presented. The incorporation of 2 atoms within the ring will then be discussed in Chapter 3 with the synthesis of hydantoins, imidazolones, thiazolines, pyrazoles and phthalazinones. Chapter 4 will focus on the incorporation of every atom in the heterocycle to form other bioactive cores such as azauracils, pyridazinones and azadiketopiperazines. Lastly, Chapter 5 will describe our efforts for the synthesis of acyclic molecules such as semicarbazides and aza-peptides.
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Osborn, Helen M. I. "Activated aziridines as versatile intermediates organic synthesis". Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238927.

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Swindlehurst, Marianne. "Ethoxyvinylarenes as versatile intermediates for heterocycle synthesis". Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/841208/.

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In the field of drug discovery, pyrrolopyridine moieties are often incorporated into bioactive molecules. This is due to their ability to form both pi-stacking and hydrogen bonding interactions when binding to target proteins. This project aimed to provide a robust and rapid method of synthesis that will provide access to substituted pyrrolopyridines. The work is based on a previously published method involving the synthesis of ethoxyvinyl(amino)arenes, by Suzuki reaction of halo-aminoarenes, followed by cyclisation. It was hoped this method would be advanced by applying alternative cyclisation reactions to the ethoxyvinyl(amino)arenes to give 3-substituted products in one step. In comparison with previous methods, this route would be inexpensive, robust and applicable to a wide range of substrates. It was also envisaged that alternative starting materials could be used to make it a more generalised method for the synthesis of bicyclic arenes. Work began with testing the reproducibility of the previously published method of synthesising the ethoxyvinyl(amino)arenes. This was done successfully, although a change in ligand (SPhos to RuPhos) proved beneficial, with seven different analogues being synthesised in yields ranging from 36% to 98%. This same reaction was attempted with halo-hydroxypyridines, with a novel route to furopyridines in mind, but with no success. The synthesis of non-commercially available halo-hydroxypyridines themselves also proved to be challenging with no material being isolated. Various methods were tested for the bromo-cyclisation of ethoxyvinyl(amino)arenes to 3-bromopyrrolopyridines. A two-step method using acid cyclisation followed by bromination was entirely successful. Two-step, one-pot and one-step methods both appeared to promote polymerisation/oligermisation. Success was achieved with a one-step method employing an acid additive but only on selected ethoxyvinyl(amino)arene isomers and with varying yields. The work was extended to the attempted synthesis of anti-malarial precursors using the bromo-pyrrolopyridine isomers as building blocks and converting them to alkyl-linked glutarimides. This led to the successful and novel synthesis of the reactants vinyl glutarimide and glutarimylethylborolane. However, successful conditions for their palladium catalysed cross coupling with the bromides were not found.
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Hadden, Mark. "Enamides and enaminones : versatile intermediates for heterocycle formation". Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322956.

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McIntyre, Peter Brian Alexander. "Chemoenzymatic oxidation of arenes : versatile intermediates for organic synthesis". Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602501.

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Chapter 2 describes the chemoenzymatic synthesis of (-)epibatidine from a known cis-dihydrodiol. Crucia to the synthesis is a [3.3] sigmatropic rearrangement reaction. Two [3.3] sigmatropic rearrangements are described ; an allylazide rearrangement and an allylcyanate to isocyanate rearrangement. The synthesis was completed in eleven steps, yielding (~) -epibatidine in 21% yield. Chapter 3 describes the synthesis and characterisation of allytic cyetic sulphates from known cis~ tetrahydrodiols. These cyclic sulphates are ubiquitous synthetic intermediates, commonly used as electrophiles. Also described is the synthesis of a series of trans-1 ,2-chloro chlorosulphates. These compounds are by-products in the formation of cyclic sulphates and can be avoided by careful control of the reaction conditions. Chapter 4 describes the small-scale biotransformations of a series of substituted phenol metabolites, using the toluene dioxygenase (TOO) enzyme. The cyclohexenone cis-dial products are characterised fully and their absolute configurations are established using a variety of methods, including circular dichroism and stereochemical correlation. Pseudomonas putida UV4 and E.coli were used as sources of TOO for these reactions. Also described is the large-scale biotransformation of two of these phenols. The chemical synthesis of the cyclohexenone cis-diol products from known cistetrahydrodiols is also described as an alternative route to these compounds. Finally, the biotransformation of several substituted anilines using TOO is also described.
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McCreanor, Niall G. "Rhodacyclopentanones as versatile catalytic intermediates for the synthesis of complex scaffolds". Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702463.

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The catalytic generation of rhodacyclopentanone intermediates from readily accessible substituted cyclopropane precursors and feed stock CO has enabled the synthesis of a range of complex structures. Access to these 'sp3-rich' intermediates relies on a directing group strategy which facilitates their regioselective formation. This directing group controlled approach has enabled the development of multicomponent (3+1+2) cycloadditions between aminocyclopropanes, CO and tethered alkenes to deliver N-heterobicyclic ketones. The employment of a cationic Rh(I)-catalyst facilitated reversible formation of the rhodacyclopentanone intermediate, which was key to obtaining high levels of diastereocontrol for systems with substitution on the alkene tether. Studies on 1,2-disubstituted cyclopropane systems revealed regiodivergent processes, which are controlled by the stereochemistry of the cyclopropane (cis vs. trans). Investigations have also been conducted on systems containing tethered 1,2-disubstituted alkenes to generate products with three new C-C bonds and three new stereo genic centres. Observations during the studies summarised above have led to the identification of a second family of methodologies, where the rhodacyclopentanone is trapped by an appropriate nucleophile. Initially, an intermolecular protocol was established and moderate yields of yamino acid derivatives have been achieved by reaction of Cbz-protected aminocyclopropanes with alcohol or phenol nucleophiles. In concurrent studies, an intramolecular system was developed using urea based substrates; this afforded 7-membered enamides in high yields with excellent selectivity. Interestingly, the oxidation level of the cyclic products was dependent on the aminocyclopropyl substituents. Directed rhodacyclopentanone formation has also been extended to methylaminocyclopropane and cyclopropanamide systems, wherein the directing group forms a 6- or 4-membered chelate to the metal. This has provided a platform for the development of (3+1+2) cycloadditions for these substrate classes. Finally, whilst probing oxidative insertion into methylaminocyclopropanes, a C-C bond activation triggered hydroacylation protocol was discovered. This process results in the atom economic assembly of a-amino-substituted cyclopentanones from methylaminocyclopropane substrates.
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Da, Cruz Ana Filipa P. "C-branched carbohydrate lactones : versatile intermediates in the synthesis of branched iminosugars". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670024.

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Bower, John F. "Cyclic sulfamidates as versatile intermediates for N-heterocycle construction : applications in total synthesis". Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439953.

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Filipa, P. da Cruz Ana. "C-branched carbohydrate lactones : Versatile intermediatesin the synthesis of branched bioactive". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509913.

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Chien, Ting-Lin y 簡廷燐. "Tricarbonyliron Triene Complexes As Versatile Synthetic Intermediate". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/29201121273100930729.

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碩士
國立中山大學
化學學系
83
Organoiron complexes are readily available and can serve as starting meterials for the synthesis of numerous natural products. The synthetic applications of the tricarbonyliron triene complexes not been explored previously. The organic compound, 1-methylene-4-methoxycyclohex-2,4- diene, does not exist which will tautomerized rapidly to 4-methylanisole. The Fe(CO)3 act as a protecting and stabilizing group for the exocyclic methylene group and this has important synthetic applications. We now proposed to carry out new chemical and stereochemistry applications of a new series of organoiron complex. (1) Electrophilic substitution reaction , including trapping with nucleophiles. (2) 1,3-Dipolar cycloaddition reactions.
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Capítulos de libros sobre el tema "Versatile intermediates"

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Keglevich, György. "Phosphinine Derivatives and their Use as Versatile Intermediates in P-Heterocyclic Chemistry". En Topics in Heterocyclic Chemistry, 65–98. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/7081_2008_8.

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Fustero, Santos, Juan F. Sanz-Cervera, Julio Piera, María Sánchez-Roselló, Diego Jiménez y Gema Chiva. "Fluorinated β-Enamino Esters as Versatile Synthetic Intermediates: Synthesis of Fluorinated β-Amino Acids and Uracils". En ACS Symposium Series, 593–610. Washington, DC: American Chemical Society, 2005. http://dx.doi.org/10.1021/bk-2005-0911.ch034.

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Yamamoto, Hiroshi, Tadashi Hanaya, Kiyoshi Torigoe y Wolfgang Pfleiderer. "N 2-(N,N-Dimethylaminomethylene)-O 4-(2-p-Nitrophenyl. Ethyl)-Biopterin: A Versatile Intermediate for a Glycosidation Reaction". En Advances in Experimental Medicine and Biology, 21–24. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2960-6_3.

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Turnbull, Kenneth y Andrew J. Weisner. "o-Alkynylsydnones as Versatile Intermediates for Heterocyclic Synthesis". En 19th International Congress on Heterocyclic Chemistry, 348. Elsevier, 2003. http://dx.doi.org/10.1016/b978-0-08-044304-1.50340-3.

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D. Adesina, Adebimpe. "The Chemistry of Benzo and Carbocyclic Derivatives of Pyridine". En Exploring Chemistry with Pyridine Derivatives [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108127.

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The chemistry of pyridine and its derivatives is of considerable importance in the synthesis of intermediates leading to biologically active compounds and novel materials. Generally, derivatives of pyridine are stable and relatively unreactive but can be attacked by electrophiles at ring nitrogen and certain carbon atoms. Pyridines undergo radical substitution reactions preferentially at the 2-position. Simple pyridines and their benzo derivatives are weak bases that form salts with strong acids. Various Lewis acids form complexes with pyridine and its benzo derivatives. The quaternization of pyridine and its benzo derivatives using alkyl and acyl halides have been used as versatile synthetic intermediates to biologically active compounds as final products. Precursors to cyanine dyes have been prepared by means of the 1,4-addition of pyridines and quinolines to acrylamide. N-oxides, obtained by the oxidation of pyridine and its benzo analogues, are versatile intermediates in organic synthesis.
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Hou, Z. W. y H. C. Xu. "7 Electrochemically Generated Nitrogen-Centered Radicals". En Electrochemistry in Organic Synthesis. Stuttgart: Georg Thieme Verlag KG, 2022. http://dx.doi.org/10.1055/sos-sd-236-00136.

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Nitrogen-centered radicals are versatile reactive intermediates for organic synthesis. This chapter describes recent progress in the electrochemical generation and reactions of nitrogen-centered radicals. Under electrochemical conditions, various nitrogen-centered radicals are generated through electrolysis of readily available precursors such as N—H bonds or azides. These reactive intermediates undergo addition reactions to π-systems or hydrogen-atom abstraction to generate various nitrogen-containing compounds.
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Zhang, J., D. Liu y Y. Chen. "1.9 Oxygen-Centered Radicals". En Free Radicals: Fundamentals and Applications in Organic Synthesis 1. Stuttgart: Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/sos-sd-234-00177.

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AbstractOxygen-centered radicals (R1O•) are reactive intermediates in organic synthesis, with versatile synthetic utilities in processes such as hydrogen-atom transfer (HAT), β-fragmentation, radical addition to unsaturated carbon–carbon bonds, and rearrangement reactions. In this review, we focus on recent advances in the generation and transformation of oxygen-centered radicals, including (alkyl-, α-oxo-, aryl-) carboxyl, alkoxyl, aminoxyl, phenoxyl, and vinyloxyl radicals, and compare the reactivity of oxygen-centered radicals under traditional reaction conditions with their reactivity under visible-light-induced reaction conditions.
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Kaga, A. y H. Yorimitsu. "1.6 Sulfur-, Selenium-, and Silicon-Centered Radicals". En Free Radicals: Fundamentals and Applications in Organic Synthesis 1. Stuttgart: Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/sos-sd-234-00090.

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AbstractSulfur-, selenium-, and silicon-centered radicals are versatile reaction intermediates in modern synthetic organic chemistry. These radicals are capable of adding to carbon–carbon multiple bonds such as alkene and arenes, thus introducing the corresponding elements into the products. These radicals can also serve as mediators of free-radical reactions, including as polarity-reversal catalysts, asymmetric catalysts, and halogen-atom abstraction agents, without these elements being incorporated into the products of the reactions. This chapter describes the utility of sulfur-, selenium-, and silicon-centered radicals in two sections. The first covers reactions involving incorporation of the corresponding elements into the products, while the second describes reactions using these radicals as catalysts or reagents to prepare products that do not contain the corresponding elements.
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Malhotra, Deepika, Joyeeta Mukherjee y Munishwar N. Gupta. "Sustainability of Biocatalytic Processes". En Chemical Processes for a Sustainable Future, 388–421. The Royal Society of Chemistry, 2014. http://dx.doi.org/10.1039/bk9781849739757-00388.

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White biotechnology is largely based on the use of biocatalysts in the production of chemicals, drug intermediates, materials and biofuels. Various metrics for measuring the sustainability of a process are available and their uses often show that biocatalytic routes score over production strategies based on chemical catalysts alone. The possibility of using various reaction media, improving the performance of biocatalysts by engineering, sourcing enzymes from extremophiles, and assistance from microwave and ultrasonic radiations have all made biocatalysis more versatile and efficient. While enzyme specificity has been exploited for many years in organic synthesis, catalytic promiscuity has further expanded the range of enzymes in recent years. Finally, the concepts of biorefineries and valorization of waste complement each other and enhance the sustainability and economic viability of biocatalytic processes.
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Taber, Douglass. "Enantioselective Synthesis of Alcohols and Amines". En Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0036.

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Enantiomerically-enriched alkoxy stannanes such as 3 are versatile intermediates for synthesis. John R. Falck of UT Southwestern found (Angew. Chem. Int. Ed. 2008, 47, 6586) that the simple combination of Bu3 SnH and Et2Zn generated a reagent that added to aldehydes such as 1 under catalysis by the MIB amino alcohol introduced by Nugent (Chem. Commun. 1999, 1369) to give the adduct 3 in high ee. Gonzalo Blay and José R. Pedro of the Universitat de València showed (Chem. Commun. 2008, 4840) that it was possible to modulate the reactivity of the acidic 4, allowing catalyzed formation of the high ee adduct 5 to dominate. Xiaoming Feng of Sichuan University developed (J. Am. Chem. Soc. 2008, 130, 15770) a Ni catalyst for the intermolecular ene reaction of 6 with 7 to give 8 in high ee. Enantioselective allylation is a key transformation in current organic synthesis. Yoshito Kishi of Harvard University optimized (Organic Lett. 2008, 10, 3073) enantioselective Cr-mediated allylation, with a ligand that can be easily recovered and recycled. Michael J. Krische of UT Austin devised (J. Am. Chem. Soc. 2008, 130, 14891) a ligand-catalyst combination for effecting the enantioselective allylation of alcohols such as 12 . Brian M. Stoltz of Caltech developed (Angew. Chem. Int. Ed. 2008, 47, 6873) a protocol for the enantioselective allylation of the enol ether 15, leading to the construction of oxygenated quaternary centers. Adducts such as 11 and 17 are of interest, inter alia , as direct precursors, by elimination, of the corresponding alkynes. Simon Blakey of Emory University designed (Angew. Chem. Int. Ed. 2008, 47, 6825) a Ru catalyst that mediated enantioselective intramolecular C-H amination, converting the simple alcohol derivative 18 into the versatile secondary amine 19 in high ee. We established (J. Org. Chem. 2008, 73, 9334) a procedure, based on diazo transfer followed by Rh-mediated intermolecular N-H insertion, for aminating menthyl esters and separating the product diastereomers. The menthyl group, easily removed (TFA) from 21, served as a useful reporter of ee, by 1H NMR of the upfield methyl doublets. Wolfgang Kroutil of the University of Graz found (Adv. Synth. Cat. 2008, 350, 2761) that ω-transaminases could effect the reductive amination of methyl ketones such as 22 in high ee.
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Actas de conferencias sobre el tema "Versatile intermediates"

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Lin, Y. C., W. S. Wang, T. Gessner y M. Esashi. "Nanoporous gold as a versatile bonding intermediate". En 2014 4th IEEE International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D). IEEE, 2014. http://dx.doi.org/10.1109/ltb-3d.2014.6886185.

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Moreira, Bárbara V. y Cristiano Raminelli. "Synthesis of 3-hydroxy-2-(trimethylsilyl)phenyl trifluoromethanesulfonate as a versatile intermediate in preparative organic chemistry". En 15th Brazilian Meeting on Organic Synthesis. São Paulo: Editora Edgard Blücher, 2013. http://dx.doi.org/10.5151/chempro-15bmos-bmos2013_201391593549.

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Goujot, Daniel, Têko Gouyo, Philippe Bohuon y Francis Courtois. "A versatile simulator for defrosting, convective and boiling drying during hot air frying process". En the 7th International Food Operations and Processing Simulation Workshop. CAL-TEK srl, 2021. http://dx.doi.org/10.46354/i3m.2021.foodops.003.

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"A versatile simulator takes into account four major stages: defrosting, warm-up, and convective and boiling drying. This dynamic model considers that a frozen prefried french fries has three compartments: a central compartment (#1) with high water content, a peripheral compartment (#3) corresponding to the prefried dry crust, and an intermediate compartment (#2) appears during frying, filled with water vapour. Convective and boiling drying and freezing are modeled. The predicting model has been identified based on the triplicates of three different modalities. The resulting predictions have been experimentally validated."
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Holmes, Jeffrey W. y Thomas K. Borg. "Isotonic Biaxial Loading: An Economic, Versatile Method for the Study of Fibroblast-Populated Collagen Gels". En ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0402.

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Abstract Studies of collagen gel contraction by embedded fibroblasts have characterized the response of free (unloaded) or isometric (maximally loaded) gels but not the response to intermediate loads. An inexpensive, simple system was devised to isotonically load fibroblast-populated collagen gels using freely hanging weights. This system provided excellent repeatability. Maximal contraction force was estimated at 1 mN per million cells in neonatal rat cardiac fibroblasts, a value that agreed well with reported isometric experiments in fibroblasts from other tissues. The ability to load uniaxially or biaxially and with variable loads will facilitate exploration of the regulation of fibroblast mechanics and biology by stress.
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Paraschis, L., M. C. Bashaw, A. Liu y L. Hesselink. "Properties of Resonant Two-Photon Processes in Photorefractive Media". En Adaptive Optics. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/adop.1996.jtud.4.

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Summary Holographic data storage systems [1] require sensitive optical materials that provide some means of nondestrective readout [2]. Among the number of techniques for nonvolatile readout available [2]. the sensitazation of a photorefractive medium by illumination at one wavelength, called gating, for writing at a second using a resonant two-photon process, constitutes the most versatile all-optical nondestructive method. Typically, this process consists of absorption of a photon at frequency ω1 to generate an intermediate excited state, followed by absorption of a second at ω2 to generate a free carrier [3, 4, 5]. Gating occurs for absorption of two photons at two different wavelengths. In the present work, we identify the critical physical characteristics of the processes that provide the simultaneous realization of true gating and writing sensitivity at a variety of frequencies, evaluate the refractive index perturbation and the response rate, and investigate the significance of the the intermediate state occupancy and the arisining nonlinear photorefractive behavior at its saturation regime.
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Roßmann, Ju¨rgen, Michael Schluse y Thomas Jung. "Introducing Intuitive and Versatile Multi Modal Graphical Programming Means to Enhance Virtual Environments". En ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49517.

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Usability and versatility are two of the most important issues when using modern 3D simulation systems within the field of automation technology and virtual environments. 3D simulations and virtual worlds proved to be versatile tools to program, supervise and command complex robotic and automation systems. For industrial robots, 3D simulation systems like COSIMIR® introduced the so called Native Language Programming (NLP) concept enabling the automation expert to program each robot using its native programming language. But what about programming other automation components or other dynamic components in virtual environments, what about user friendly, intuitive graphical programming languages, what about easy-to-use worker oriented programming languages? When talking about graphical programming languages to model dynamic behavior, questions like “which graphical modeling languages should be supported?”, “which are the most powerful ones?” and “which one matches the most to my concrete application?” have to be answered. Each graphical programming language has its own advantages and disadvantages, so that the answer to all these questions has to be: Offer a choice of graphical modeling languages to the user and leave the decision to him. The advantage of this strategy is obvious: Instead of learning how to use a concrete modeling language or worrying about programming details, the user can focus on his individual automation task and so quickly build efficient solutions. Therefore this paper extends the NLP approach to graphical programming languages using a new kind of object oriented Petri Nets as an intermediate language. This enables the user to use — at the same time — finite automata like mealy machines or extended automata, activity diagrams as defined in UML 2, flowchart like diagrams (e. g. icon-based programming) and many more to model the dynamics or the behavior of dynamic components.
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Hosmane, Ramachandra, Saika Siddiqui y Bruce Gustafson. "A New Synthetic Approach toward Ring-Expanded ("Fat") Purine Nucleobases: Synthesis and Use of 5-Dichloromethyl-1-p-methoxybenzyl-4-nitroimidazole as a Versatile Intermediate." En The 3rd International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 1999. http://dx.doi.org/10.3390/ecsoc-3-01740.

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Michlik, P. y O. Racek. "XFEM Modeling of Effective Thermal Properties and Fracture of Thermal Barrier Coatings". En ITSC2005, editado por E. Lugscheider. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2005. http://dx.doi.org/10.31399/asm.cp.itsc2005p0293.

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Abstract An in-house Extended Finite Element code is employed to simulate the effect of cracks within a TBC system with a YSZ top coat and a mullite intermediate layer deposited onto a SiC substrate. Microstructural level analysis consists in decomposition of a micrograph into an image showing the crack structure and then image capturing the distribution of pores and coating materials. This later image is used to generate the adaptive Finite Element (FE) mesh while the first image defines a discontinuous enrichment of the FE approximation of the displacement field. This analysis process is versatile and takes into account the presence of the cracks within the coating so that the fracture behavior can be estimated. Stress intensity factors of selected through-thickness cracks were calculated from a domain form of the interaction integral. The concept of XFEM is also extended to thermal analysis. Again, the FE approximation is enriched in a way similar to the previous case; however the weak form is modified to enforce proper temperature changes across the crack width. The cracks are modeled as thermal insulating layers with resistance determined from the kinetic theory of gases. The effective thermal conductivity of the coating is, thereby, predicted.
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Potter, B. G. y J. H. Simmons. "Quantum-confinement effects in rf-magnetron sputtered CdTe:glass composite thin films". En OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.wo4.

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Silicate glass films containing CdTe have been produced using an rf-magnetron sputtering technique in which a fused silica substrate is alternately exposed to each of two sputtering sources holding targets of Pyrex 7740 glass and high purity CdTe. This process represents a highly versatile fabrication technique for the production of semiconductor-doped glass materials. We report the successful deposition of CdTe-doped glass films containing as much as 30 vol % semiconductor with average crystallite sizes ranging from 46 to 158 Å. Planar-view transmission electron microscopy has shown the isolated crystals of CdTe to possess a circular morphology and a zincblende crystal structure. Room temperature optical absorption measurements exhibit a clear blue-shift in the fundamental absorption edge as the average semiconductor crystal size is reduced, indicative of a substantial quantum confinement effect. Analysis of the behavior shows it to be governed by an effective mass term which is intermediate between the translational and reduced masses of the bulk CdTe Wannier exciton.1 Failure of the data to exhibit a reduced mass behavior in the absorption edge shift with crystal size suggests that a substantial Coulomb interaction between the photoexcited electron and hole still exists even at crystal sizes 0.3 times the Bohr diameter of the bulk CdTe exciton.
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Petersen, Thomas, Qian Wu, Nanjun Liu, Brian J. O’Donnell, Gene Korn, Parker Hewitt y Changjun Zhou. "Compressible Carbon: Particle Behavior in Drilling Fluids and Field-Scale Deployment". En Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/31767-ms.

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Abstract Annular pressure buildup (APB) can occur due to an increase in fluid temperature during the production of hot reservoir fluids, geomechanical loading from the surrounding rock formation, and hydraulic connectivity to pressurized reservoirs. In this study, a novel, compressible, carbonaceous fluids additive was deployed and tested for APB mitigation in a well-scale field trial. The additive is shown to appreciably reduce pressure changes in trapped, downhole volumes by increasing the fluid mixture's compressibility and reducing its thermal expansivity. The proposed additive, referred to as compressible carbon, is a granular spongy carbon with an internal porosity that remains closed to fluid ingress. Lab-scale results demonstrate the durability of compressible carbon in high temperature and high pressure environments when immersed in typical drilling fluids. At a loading of 20% by volume, the use of carbon reduced pressure buildup by 30%-50% relative to reference measurements performed in fluids without carbon. Moreover, the particles showed no long-term relaxation while being held at 10,000 psi and 220°F for up to three months, and exhibited only a marginal loss in reversible compressibility over 100s of pressure cycles between 500psi and 13,500psi. Following the material's characterization in the lab, field trial results were collected during the deployment and testing of carbon in two unconventional land wells above the cemented section of the production-by-intermediate annulus. Wireline logging on both wells confirmed minimal fluid losses to the formation and an adequate cement barrier that reached above the outer-lying casing shoes. Field-scale performance of compressible carbon was confirmed by pressuring up on the annuli at surface and comparing the injection volumes to those collected on an offset well without carbon. Although alternate methods of reducing pressure buildup in wells exist, compressible carbon is a versatile new material that provides repeated APB relief across the pressure ranges that are relevant to deepwater wells. To minimize the risk of first application in deepwater wells, successful deployment and expected performance were demonstrated in two unconventional land wells, paving the way for subsequent applications offshore.
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