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Relevant bibliographies by topics / Novel reactive intermediates

Academic literature on the topic 'Novel reactive intermediates'

Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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Dissertations / Theses
Book chapters
Conference papers

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Journal articles on the topic "Novel reactive intermediates"

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Hemberger, Patrick, Jeroen A. van Bokhoven, Javier Pérez-Ramírez, and Andras Bodi. "New analytical tools for advanced mechanistic studies in catalysis: photoionization and photoelectron photoion coincidence spectroscopy." Catalysis Science & Technology 10, no. 7 (2020): 1975–90. http://dx.doi.org/10.1039/c9cy02587a.

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Damsten, Micaela C., Jon S. B. de Vlieger, Wilfried M. A. Niessen, Hubertus Irth, Nico P. E. Vermeulen, and Jan N. M. Commandeur. "Trimethoprim: Novel Reactive Intermediates and Bioactivation Pathways by Cytochrome P450s." Chemical Research in Toxicology 21, no. 11 (November 17, 2008): 2181–87. http://dx.doi.org/10.1021/tx8002593.

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Kessar, S. V. "Lewis acid complexed azacarbanions: Novel reactive intermediates of wide synthetic utility." Pure and Applied Chemistry 68, no. 3 (January 1, 1996): 509–14. http://dx.doi.org/10.1351/pac199668030509.

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Hansel, Colleen M., Timothy G. Ferdelman, and Bradley M. Tebo. "Cryptic Cross-Linkages Among Biogeochemical Cycles: Novel Insights from Reactive Intermediates." Elements 11, no. 6 (November 30, 2015): 409–14. http://dx.doi.org/10.2113/gselements.11.6.409.

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Green, Justin L., and Gregory A. Reed. "Benzo[a]pyrene bay-region sulfonates, a novel class of reactive intermediates." Chemical Research in Toxicology 3, no. 1 (January 1990): 59–64. http://dx.doi.org/10.1021/tx00013a010.

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Thome, Ulrich, Ahmed Lazrak, Lan Chen, Marion C. Kirk, Michael J. Thomas, Henry Jay Forman, and Sadis Matalon. "Novel SIN-1 reactive intermediates modulate chloride secretion across murine airway cells." Free Radical Biology and Medicine 35, no. 6 (September 2003): 662–75. http://dx.doi.org/10.1016/s0891-5849(03)00392-7.

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Attwa, Mohamed W., Adnan A. Kadi, and Hany W. Darwish. "Belizatinib: Novel reactive intermediates and bioactivation pathways characterized by LC–MS/MS." Journal of Pharmaceutical and Biomedical Analysis 171 (July 2019): 132–47. http://dx.doi.org/10.1016/j.jpba.2019.04.006.

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Groves, John T. "Cytochrome P450 enzymes: understanding the biochemical hieroglyphs." F1000Research 4 (July 1, 2015): 178. http://dx.doi.org/10.12688/f1000research.6314.1.

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Cytochrome P450 (CYP) enzymes are the primary proteins of drug metabolism and steroid biosynthesis. These crucial proteins have long been known to harbor a cysteine thiolate bound to the heme iron. Recent advances in the field have illuminated the nature of reactive intermediates in the reaction cycle. Similar intermediates have been observed and characterized in novel heme-thiolate proteins of fungal origin. Insights from these discoveries have begun to solve the riddle of how enzyme biocatalyst design can afford a protein that can transform substrates that are more difficult to oxidize than the surrounding protein architecture.

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He, Chao, Galiya R. Galimova, Yuheng Luo, Long Zhao, André K. Eckhardt, Rui Sun, Alexander M. Mebel, and Ralf I. Kaiser. "A chemical dynamics study on the gas-phase formation of triplet and singlet C5H2carbenes." Proceedings of the National Academy of Sciences 117, no. 48 (November 16, 2020): 30142–50. http://dx.doi.org/10.1073/pnas.2019257117.

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Since the postulation of carbenes by Buchner (1903) and Staudinger (1912) as electron-deficient transient species carrying a divalent carbon atom, carbenes have emerged as key reactive intermediates in organic synthesis and in molecular mass growth processes leading eventually to carbonaceous nanostructures in the interstellar medium and in combustion systems. Contemplating the short lifetimes of these transient molecules and their tendency for dimerization, free carbenes represent one of the foremost obscured classes of organic reactive intermediates. Here, we afford an exceptional glance into the fundamentally unknown gas-phase chemistry of preparing two prototype carbenes with distinct multiplicities—triplet pentadiynylidene (HCCCCCH) and singlet ethynylcyclopropenylidene (c-C5H2) carbene—via the elementary reaction of the simplest organic radical—methylidyne (CH)—with diacetylene (HCCCCH) under single-collision conditions. Our combination of crossed molecular beam data with electronic structure calculations and quasi-classical trajectory simulations reveals fundamental reaction mechanisms and facilitates an intimate understanding of bond-breaking processes and isomerization processes of highly reactive hydrocarbon intermediates. The agreement between experimental chemical dynamics studies under single-collision conditions and the outcome of trajectory simulations discloses that molecular beam studies merged with dynamics simulations have advanced to such a level that polyatomic reactions with relevance to extreme astrochemical and combustion chemistry conditions can be elucidated at the molecular level and expanded to higher-order homolog carbenes such as butadiynylcyclopropenylidene and triplet heptatriynylidene, thus offering a versatile strategy to explore the exotic chemistry of novel higher-order carbenes in the gas phase.

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Kotuniak, Radosław, and Wojciech Bal. "Kinetics of Cu(ii) complexation by ATCUN/NTS and related peptides: a gold mine of novel ideas for copper biology." Dalton Transactions 51, no. 1 (2022): 14–26. http://dx.doi.org/10.1039/d1dt02878b.

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The aim of this perspective is to help revive studies of the kinetics of formation and exchange in Cu(ii)–peptide complexes. Such studies have the power to reveal novel reactive intermediates and set timeframes for actual physiological processes.

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Dissertations / Theses on the topic "Novel reactive intermediates"

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Sasaki, Ikuo. "Development of Novel Synthetic Methods of Organosilicon Compounds Utilizing Silicon-Containing Reactive Intermediates." Kyoto University, 2020. http://hdl.handle.net/2433/253508.

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Campbell, Steven John. "Novel methods to characterise atmospherically relevant organic radicals and reactive oxygen species." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274099.

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A key reaction in the troposphere involves the oxidation of biogenic and anthropogenic alkenes with ozone, which contributes to local photochemical smog. It is generally accepted that this reaction proceeds via a reactive intermediate often called the Criegee intermediate (CI). This reaction is known to produce a plethora of oxidised organic compounds, which contribute to ozone formation and secondary organic aerosol production, two of the main characteristics of a polluted atmosphere. Furthermore, epidemiological studies have shown a close correlation between exposure to ambient organic aerosol and adverse human health effects. The toxicological mechanisms leading to this observation are still poorly characterised, although studies suggest that reactive oxygen species present in organic aerosol are a major contributor. Reactive oxygen species and reactive intermediates represent a large uncertainty in tropospheric chemistry, and pose an analytical challenge due to their high reactivity and typically low concentrations. This emphasises the need for the development of new methods to characterise the chemistry of these species. In this thesis, several novel laboratory based techniques have been developed in order to characterise and quantify reactive intermediates and reactive oxygen species. New methods to facilitate the detection of CIs in both the gas and particle phase are presented. Spin trap molecules are used to scavenge CIs to form stable 1:1 adducts which are subsequently detected and quantified using mass spectrometry. The chemistry of CIs with spin traps is extensively investigated. The unique capability of this technique to simultaneously characterise multiple CIs generated from a variety of atmospherically relevant organic precursors in the gas phase is demonstrated. This technique was further developed to facilitate the detection of CIs in secondary organic aerosol, representing the development of a method capable of characterising low volatility CIs and other reactive intermediates in the condensed phase. Furthermore, two new chemical fluorescence assays have been developed to quantify both organic radicals and reactive oxygen species in organic aerosol. A novel profluorescent spin trap assay was applied to quantify radical concentrations in organic aerosol. A series of experiments were then devised to investigate the lifetime of organic radicals in secondary organic aerosol. A second assay, based on physiologically relevant ascorbic acid chemistry, was also developed to measure the concentrations of toxicologically relevant reactive oxygen species in secondary organic aerosol. The quantitative capability of this assay was extensively characterised. The assay was incorporated into a prototype instrument capable of measuring particle-bound reactive oxygen species on-line, and the assays’ sensitivity to secondary organic aerosol was demonstrated.

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Hirayama, Lacie C. "Novel reactions of organoindium compounds : the synthesis of chiral alcohols, allylboron reagents and identification of the reactive intermediates /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.

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Murrin, Andrew T. "N-Glycosyl Aza-Ylides as Intermediates in the Synthesis of Novel N-Glycosides." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1590679639104474.

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Xu, Chang. "A Novel Mass Spectrometry Method to Study Reaction Intermediates and Development of AuTeCDs for Scavenging ROS in Live Cells." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1597326111937675.

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Welsh, Kevin M. "The generation and characterization of novel organosilicon reactive intermediates 1,4-disilabenzenes, di-tert-butylsilylene and N, N'-di-tert-butylsilanediimine /." 1987. http://catalog.hathitrust.org/api/volumes/oclc/16004488.html.

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Sun, Kuo-Hui, and 孫國惠. "Ene Reaction with Pummerer-type Reaction Intermediate of α-( Methylthio)acetic Acid Pyrrolidide : A Novel Synthesis of Trichonine." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/09339185613058770651.

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碩士
高雄醫學院
藥學研究所
86
Dienamide 基團在許多天然物成份中是很重要的結構特徵，曾有報告指出 dienamide具生理活性，尤其是可做為殺蟲劑。而由 P. trichostachyon leaves 所分離出來的Trichonine [(E,E)-2,4- eicosadienoic acid pyrrolidide] 即是一種含有殺蟲效果的化合物，它曾經由 Wittig 反應及脫去反應合成出來。本計劃分別利用 methyl α-( methylthio)acetate 及 α-(methylthio)acetic acid pyrrolidide 當原料，和高價碘試劑 phenyliodine(III) bis(trifluoroacetate) (PIFA) 反應，形成 Pummerer-type 反應中間體，然後與烯類進行 ene 反應來合成 Trichonine。 The dienamide group is an important structural feature of a number of naturalproducts, which have been reported to be biologically active, especially as insecticides. Trichonine [(E, E)-2,4-eicosadienoic acid pyrrolidide] is an insecticidal compound isolated from P. trichostachyon leaves, has been synth- esized by Wittig reaction and elimination reaction. In this work we wish toreport that the Pummerer-type reaction intermediate derived from α-(methylt-hio)acetic acid pyrrolidide and phenyliodine(III) bis(trifluoroacetate) (PIFA)undergoes an ene reaction with 1-alkenes to give the ene adducts and its app- lication to the synthesis of Trichonine.

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Zhang, Ji. "The synthesis of several novel non-benzenoid aromatic compounds by use of thiophene intermediates and annulene coupling reaction." Thesis, 1997. https://dspace.library.uvic.ca//handle/1828/9795.

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One of the main objectives of this Thesis was to explore the use of thiophenes to synthesize several more complex aromatic systems. Thus starting from 2,4-dimethyl 5- amino-3-methylthiophene-2,4-dicarboxylate 115, the synthesis of the first cis-thia[ 13]annulene, 4-bromo-cis-9b,9c-dimethyl-9b,9c-dihydrophenyleno[1,9-bc]thiophene 116a, as well as the trans-isomer, 116b have been achieved in 11 steps. Introduction of a bromo-substituent at an early stage, facilitated rearrangement of the thiacyclophanes 119a and 119b to permit easier isolation of the product annulenes. Both the cis-thia[ 13]annulene 116a and the trans-thia[ 13]annulene 116b were found to be diatropic on the basis of their 1H NMR chemical shifts. Using thiophene dioxide 150 and 152 as key intermediates to generate multifunctional azulenes, the novel azulene containing thiacyclophane 105 has been synthesized in 9 steps. Even though this was not able to be converted to the [18]annulene 100, discovery of a new route to thiacyclophanes from thiolacetates was achieved. This has been tested successfully on a variety of other examples, including the unusual bis thiophene containing cyclophanes 194 and 195, as well as the unsymmetrical 191 which was subsequently converted to the dihydropyrene 236a and 236b. During the course of this work, we discovered a new mild method to electrophilically brominate reactive aromatics using NBS in [special characters omitted] at room temperature. This reagent was investigated for several thiophenes, azulenes and dihydropyrenes. The products from the latter were successfully coupled using Ni(0) catalysis to generate 28% of the first unsymmetrically connected dimer of DMDHP, 249, as well as 33% of the symmetrical dimer 102. Unlike 102, the bi-annulenyl 249 has a significant barrier to rotation, which is estimated as 11.0 kcal/mole from [special characters omitted] measurement, compared to a PCMODEL calculated barrier of 12 kcal/mole. This is the first measurement of the barrier to rotation in a 1,2'-binaphthyl type system. Electrophilic substitution in DMDHP using the diazonium salts 277 and 283 was also studied, and several novel cross-coupling products have been synthesized and isolated, such as 278 from 279 and 280. As well the very unusual isomeric quinones, 7-(10b, 10c-dimethyl-7-oxo- 2,7,10b, 10c-tetrahydro-2-pyrenyliden)-10b, 10c-dimethyl-2,7-10b, 10c-tetrahydro-2- pyrenone 263 and 264 have been successfully prepared by reacting 102 with NBS or PDC. Compounds 263 and 264 have highly extended conjugated systems.
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Book chapters on the topic "Novel reactive intermediates"

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Logan, C. J., D. Hesk, and D. H. Hutson. "The Fate of 4-Cyanoacetanilide in Rats and Mice: The Mechanism of Formation of a Novel Electrophilic Metabolite." In Biological Reactive Intermediates III, 749–53. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-5134-4_69.

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Treacy, S., X. Zhang, and T. Rovis. "1.13 Intramolecular Hydrogen-Atom Transfer." In Free Radicals: Fundamentals and Applications in Organic Synthesis 1. Stuttgart: Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/sos-sd-234-00299.

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AbstractRecent advances in intramolecular hydrogen-atom transfer (HAT) have demonstrated significant utility in C—H functionalization through highly reactive open-shell intermediates. The intramolecular transposition of radical reactivity from select functional groups to generate more stable carbon-centered radicals often proceeds with high regioselectivity, providing novel bond disconnections at otherwise inert and largely indistinguishable positions. This chapter explores the functional groups capable of intramolecular HAT to generate remote radicals and the transformations currently available to the synthetic chemist.

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Barton, Derek H. R., and Shyamal I. Parekh. "Novel – and – Bond Metatheses.: Mechanistic Probes, Spectroscopic Studies, and Structural Evidence for Reactive Oligomeric Selenoazyl Intermediates." In World Scientific Series in 20th Century Chemistry, 533–39. WORLD SCIENTIFIC / IMPERIAL COLLEGE PRESS, 1996. http://dx.doi.org/10.1142/9789812795984_0090.

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Rademann, Jörg. "Advanced Polymer Reagents Based on Activated Reactants and Reactive Intermediates: Powerful Novel Tools in Diversity-Oriented Synthesis." In Methods in Enzymology, 366–90. Elsevier, 2003. http://dx.doi.org/10.1016/s0076-6879(03)69020-8.

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Taber, Douglass. "Intermolecular and Intramolecular Diels-Alder Reactions: (-)-Oseltamivir (Fukuyama), Platensimycin (Yamamoto) and 11,12-Diacetoxydrimane (Jacobsen)." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0078.

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Powerful methods for catalytic, enantioselective intermolecular Diels-Alder reactions have been developed. Ben L. Feringa and Gerard Roelfes of the University of Groningen have shown (Organic Lett. 2007, 9, 3647) that a catalyst prepared by combining salmon testes DNA with a Cu complex directed the absolute sense of the addition of 1 to cyclopentadiene 2 . Mukund P. Sibi of North Dakota State University has reported (J. Am. Chem. Soc . 2007, 129 , 395) related work with achiral pyrazolidinone dienophiles and chiral Cu catalysts. Tohru Fukuyama of the University of Tokyo found (Angew. Chem. Int. Ed . 2007, 46, 5734) that the MacMillan catalyst 5 was effective at mediating the addition of acrolein 4 to the pyridine-derived diene 3, enabling an enantioselective synthesis of the prominent antiviral (-)-oseltamivir (tamiflu) 7. Hisashi Yamamoto of the University of Chicago has demonstrated (J. Am. Chem. Soc . 2007, 129, 9534 and 9536) that the novel catalyst 10 effected addition of methyl acrylate 9 to the diene 8, leading to an elegant enantioselective synthesis of the tetracycle 12, the key intermediate in the Nicolaou synthesis of platensimycin. New illustrations of the power of the intramolecular Diels-Alder reaction have been put forward. Demonstrating the influence of a single subsituent on the tether, William R. Roush of Scripps/Florida found (Organic Lett . 2007, 9, 2243) that cyclization of 13 led to the diastereomer 14, complementary to the result observed with an acyclic triene. Ryo Shintani and Tamio Hayashi of Kyoto University have extended (Angew. Chem. Int. Ed . 2007, 46, 7277) their studies of chiral diene-based Rh catalysts to the enantioselective cyclization of alkynyl dienes such as 16. Jonathan W. Burton of the University of Oxford and Andrew B. Holmes of the University of Melbourne employed (Chem. Commun . 2007, 3954) the MacMillan catalyst 5 for the cyclization of 18 to 19. It is impressive that ent- 5 catalyzed the cyclization of 18 cleanly into the diastereomer of 19 in which both of the newly-created stereogenic centers were inverted.

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Sheppard, R. C. "Introduction — a retrospective viewpoint." In Fmoc Solid Phase Peptide Synthesis. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780199637256.003.0005.

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The Chemical Society publication Annual Reports on the Progress of Chemistry for 1963 attempted to inform readers of all the highly significant advances in all the major fields of pure chemistry during that year. Fortunately, the section on peptide chemistry drew attention to a paper by R. B. Merrifield which had just been published in the Journal of the American Chemical Society: A novel approach to peptide synthesis has been the use of a chloromethylated polystyrene polymer as an insoluble but porous solid phase on which the coupling reactions are carried out. Attachment to the polymer constitutes protection of the carboxyl group (as a modified benzyl ester), and the peptide is lengthened from its amino-end by successive carbodiimide couplings. The method has been applied to the synthesis of a tetrapeptide, but incomplete reactions lead to the accumulation of by products. Further development of this interesting method is awaited. I remember thinking at the time that in this paper we had possibly seen both the beginning and the end of the interesting new technique of solid phase peptide synthesis. To many organic chemists, the described result was that anticipated—difficulty in bringing heterogeneous reactions to completion resulting in impure products. Both this and purification problems were expected to worsen as the chain length was increased beyond Merrifield’s tetrapeptide limit. In fact, I probably had at the time an inadequate appreciation of the difference between truly heterogeneous or surface reactions and those in the solvated gel phase. The latter approaches much more closely the solution situation. However, the new technique also flouted many of the basic principles of contemporary organic synthesis which required rigorous isolation, purification, and characterization regimes following each synthetic step. In Merrifield’s new technique, isolation consisted simply of washing the solid resin, there was no other purification of the products of each reaction, and little or no characterization of resin-bound intermediates was attempted. The first two of these are of course the important characteristics which give the method its speed and simplicity and contribute to its efficiency. Small wonder, though, that in many minds there was doubt about the future of the new technique.

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Taber, Douglass. "Enantioselective Assembly of Oxygenated Stereogenic Centers." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0032.

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Reaction with an enantiomerically-pure epoxide is an efﬁcient way to construct a molecule incorporating an enantiomerically-pure oxygenated stereogenic center. The Jacobsen hydrolytic resolution has made such enantiomerically-pure epoxides readily available from the corresponding racemates. Christopher Jones and Marcus Weck of the Georgia Institute of Technology have now (J. Am. Chem. Soc. 2007, 129, 1105) developed an oligomeric salen complex that effects the enantioselective hydrolysis at remarkably low catalyst loading. Any such approach depends on monitoring the progress of the hydrolysis, usually by chiral GC or HPLC. In a complementary approach, we (J. Org. Chem. 2007, 72, 431) have found that on exposure to NBS and the inexpensive mandelic acid 2, a terminal alkene such as 1 was converted into the two bromomandelates 3 and 4. These were readily separated by column chromatography. Individually, 3 and 4 can each be carried on the same enantiomer of the epoxide 5. As 3 and 4 are directly enantiomerically pure, epoxide 5 of high ee can be prepared reliably without intermediate monitoring by chiral GC or HPLC. Another way to incorporate an enantiomerically-pure oxygenated stereogenic center into a molecule is the enantioface-selective addition of hydride to a ketone such as 6. Alain Burgos and his team at PPG-SIPSY in France have described (Tetrahedron Lett. 2007, 48, 2123) a NaBH4 -based protocol for taking the Itsuno-Corey reduction to industrial scale. In the past, aldehydes have been efficiently α-oxygenated using two-electron chemistry. Mukund P. Sibi of North Dakota State University has recently (J. Am. Chem. Soc. 2007, 129, 4124) described a novel one-electron alternative. The organocatalyst 10 formed an imine with the aldehyde. One-electron oxidation led to an α-radical, which was trapped by the stable free radical TEMPO to give, after hydrolysis, the α-oxygenated aldehyde 11. High ee oxygenated secondary centers can also be prepared by homologation of aldehydes. Optimization of the enantioselective addition of the inexpensive acetylene surrogate 13 was recently reported (Chem. Commun. 2007, 948) by Masakatsu Shibasaki of the University of Tokyo. Note that the free alcohol of 13 does not need to be protected.

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Conference papers on the topic "Novel reactive intermediates"

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Rajagopalan, Raghavan, Amol Karwa, Przemyslaw M. Lusiak, Kripa Srivastava, Amruta R. Poreddy, Raghootama S. Pandurangi, Karen P. Galen, William L. Neumann, Gary E. Cantrell, and Richard B. Dorshow. "Novel type 1 photosensitizers: viability of leukemia cells exposed to reactive intermediates generated in situ by in vitro photofragmentation." In 12th World Congress of the International Photodynamic Association, edited by David H. Kessel. SPIE, 2009. http://dx.doi.org/10.1117/12.822840.

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Pine, Thomas, Anh-Tuan V. Do, Li Zhao, and Jacob Brouwer. "Operation of a Novel Dry Hydrocarbon Tolerant Intermediate Temperature Solid Oxide Fuel Cell." In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85094.

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Many factors including lower materials cost for stack and balance of plant components drive an effort to reduce the operating temperature of SOFCs. Sr- and Mg-doped LaGaO3 (LSGM) has gained popularity as an intermediate temperature electrolyte due to its high oxygen conductivity. However, challenges remain regarding its mechanical strength and the lack of suitable electrode materials due to incompatibilities with conventional anode and cathode materials. Additionally, operation of conventional solid oxide fuel cells on dry hydrocarbon gas streams is precluded by the catalyzed formation of carbon whiskers within the matrix of nickel-based anodes. The incompatibility of LSGM with conventional anodes allows for investigation of other benefits of a Ni free anode; among which are hydrocarbon tolerance and redox stability. LSGM electrolyte supported cells were fabricated to test the performance and hydrocarbon tolerance of a Ni-free materials set. The composite anode was comprised of Sr-, Mg- and Co-doped LaGaO3 (LSGMC), La-doped CeO2 (LDC) as a catalytic component and Y-doped SrTiO3 as a conductive component. The cathode was made from a composite of LSGMC and Sm-doped SrCoO3. Materials were synthesized by wet chemical methods, characterized and fabricated into durable cells of high quality. The processing conditions of anode conductive components are discussed as an important factor impacting the performance of the cells. The cells were tested in dry methane and hydrogen. Testing showed cell voltages very near theoretical voltage indicating that sealing and electrolyte quality were excellent. Temperature cycling performance and post-test inspection showed that durability of the materials set was achieved. The cell showed a low power density when operating on hydrocarbons directly. Cells had no visible degradation in performance or coking after operation on dry hydrocarbons, in stark contrast to nickel-based anode performance under the same operating conditions. Poor catalytic activity to the reforming process and direct reaction of methane were found to contribute to the overall low performance. Strategies for improving catalytic activity without introducing coke-promoting materials are discussed.

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Zhang, Xiaodong, Min Xu, Li Sun, Rongfeng Sun, Feipeng Cai, and Dongyan Guo. "Biomass Gasification for Syngas Production." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90591.

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For the concern with environment protection and energy security, much attention has been paid to alternative fuels from renewable resources in modern times, among which liquid fuel production from biomass gasification has aroused much enthuasitics. One two-stage gasification technology is proposed to promote the produciton of syngas suitable for F-T synthesis. The novel technology combines moving-bed pyrolysis, the secondary reinforcement decomposition, and reduction of pyrolysis intermediates. With the addition of certain amount of oxygen in the reaction scheme, large portion of large molecular hydrocarbons and some methane in the pyrolysis gas are reformed into hydrogen and carbon monoxide, and downstream reduction process also helps the mitigation of carbon dioxide emission. The secondary gasification stage proves to be effective in adjusting the product syngas composition to accommodate the requirment of the succeeding synthesis process. From preliminary test on pilot scale experimental facility, syngas with about the same content of hydrogen and carbon monoxide was achieved, with little content of tar. With water gas shift reaction, hydrogen content can be further increased to above 45 percent, resulting suitable H2/CO for downstream synthesis process.

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Wong, Chee Wah, Nicolas Sluys, Mohd Khirfan, Nitheesh Kumar Unnikrishnan, Saleh Al Ameri, and Sultan Mohamed Al Yamani. "A Novel Engineered Drilling Solution for Improving Backreaming and Drilling Efficiency." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211787-ms.

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Abstract The wells were drilled in the Al Nouf field which is part of The Northeast Bab (NEB) fields comprise three major structures containing some of ADNOC Onshore's largest oil reserves namely Al Nouf, Rumaitha and Shanayel, covering approximately 1,200 square kilometers and located approximately 60 km west of Abu Dhabi city. The main hydrocarbon reservoirs in these structures are Kharaib-2 (Thamama Zones ‘B’) and Kharaib-1 (Thamama Zones ‘C’). The Al Nouf field lies on a coastal/shallow marine area and presents special environmental concerns due to the proximity of delicate coastal ecologies, while the Rumaitha and Shanayel fields are located entirely onshore, in a desert region some 30 km onshore from the coastline. The wells drilled in Al Nouf fields are cluster ERD wells with 10m spacing which are deviated from the surface. The drilling challenges include surface collision risks, unconsolidated surface formations in the surface section and total loss zones, and highly reactive shales in the intermediate section. Extensive back reaming while pulling the string out of hole may be required, with challenges often localized across problematic formations but also spreading across the entire open hole section. Mud rheology modifications have not proved effective in mitigating back-reaming events, so a new approach has been investigated consisting of the integration of a reaming stabilizer within the bottom hole assembly (BHA). The customized reaming stabilizer is designed with passive Polycrystalline Diamond Compact (PDC) cutters mounted on the leading and trailing edges of the blades, while Tungsten Carbide Inserts (TCI) are fitted along the gauge. The tool replaced the upper-most conventional stabilizer to provide a much more efficient reaming ability while limiting any impact on the directional behavior and bending stress state of the BHA. The paper will discuss how the substitution of conventional stabilizers within the drilling BHA with dedicated reaming stabilizers resulted in significant improvement in the wellbore condition, allowing drilling and back-reaming operations to be more efficient, and has ultimately helped drive the well construction cost down.

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Lozza, Giovanni, Paolo Chiesa, Matteo Romano, and Paolo Savoldelli. "Three Reactors Chemical Looping Combustion for High Efficiency Electricity Generation With CO2 Capture From Natural Gas." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90345.

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Chemical-Looping Combustion (CLC) is a process where fuel oxidation is accomplished by the oxygen carried by a metal oxide, circulating across two reactors: a reduction reactor (reducing the metal oxide by oxidizing the natural gas fuel) and an oxidation reactor (re-oxidizing the metal by reacting with air, a strongly exothermic reaction). The system produces: (i) a stream of oxidation products (CO2 and H2O), ready for carbon sequestration after water separation and CO2 liquefaction; (ii) a stream of hot air (deprived of some oxygen) used as working fluid of a gas turbine cycle. Due to the moderate temperature (∼850°C) of this stream, sensibly lower than those adopted in commercial gas turbines, the combined cycle arranged around this concept suffers from poor conversion efficiency and, therefore, economics. In the present paper, the basic CLC arrangement is modified by inserting a third reactor in the loop. This reactor, by exploiting an intermediate oxidation state of the circulating metal, produces H2 used as decarbonized fuel to raise the temperature of the air coming from the oxidation reactor, up to the highest value allowed by the modern gas turbine technology (∼1350°C), thus achieving elevated efficiency and specific power output. This paper is aimed to assess the potential of power cycles based on the three reactors (CLC3) arrangement. More specifically, we will discuss the plant configuration, the process optimization and the performance prediction. Results show that the CLC3 system is very promising: the net LHV efficiency of the best configuration exceeds 51%, an outstanding figure for a natural gas power cycle producing liquid, disposal-ready CO2 and negligible NOx emissions. Commercial gas turbines can be easily adapted to operate in the specific conditions of the CLC3 arrangement which, apart from the reactors system, does not require the development of novel technologies and/or high-risk components. The paper also reports a final comparison with a rival technology based on natural gas partial oxidation, water-gas shift reaction and CO2 separation by MDEA absorption. This work has been performed within the research on the Italian Electrical System “Ricerca di Sistema”, Ministerial Decrees of January 26 – 2000, and April 17 – 2001.

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Tripathi, Abhinav, Chen Zhang, and Zongxuan Sun. "Experimental Investigation and Analysis of Auto-Ignition Combustion Dynamics." In ASME 2018 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/dscc2018-9184.

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From engine controls’ perspective, understanding autoignition dynamics is a key to enabling new combustion modes for internal combustion engines, especially for renewable fuels. Conventional autoignition investigations of fuels commonly involve a rapid compression of oxidizer-fuel mixture to a desired set of temperature-pressure conditions in a rapid compression machine (RCM), and subsequent measurement of the ignition delay. However, even for relatively close thermal states at the compressed condition, different thermodynamic paths (pressure-temperature histories) may lead to significantly different chemical kinetic states and hence significantly different ignition delay measurements. Currently, there exists no systematic method to study this path dependence of auto-ignition. In this work we present, for the first time, a systematic framework for investigation of the effect of small perturbations in the thermo-kinetic states, caused by perturbing the thermodynamic path of compression, on the ignition delay of fuels from a dynamical systems perspective. First, we introduce a novel controlled trajectory rapid compression and expansion machine (CT-RCEM) which offers the ability to precisely control the piston trajectory during compression of the fuel-oxidizer mixture, allowing the thermodynamic path to be tailored as desired. We use the CT-RCEM to experimentally investigate the influence of compression trajectory perturbation on the ignition delay of a specific fuel — dimethyl-ether (DME). Next, using a reduced order model of the combustion dynamics in the CT-RCEM that we developed, we investigate the evolution of the perturbation in the thermo-kinetic states resulting from trajectory perturbation to explain the experimental observations. Finally, we show that the sensitivity of auto-ignition to the thermodynamic path perturbation essentially arises from changes in the chemical reaction rates due to different amounts of intermediate species buildup for different thermodynamic paths.

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