• Title/Summary/Keyword: reactions

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Efficient Synthesis of Spirobarbiturates and Spirothiobarbiturates Bearing Cyclopropane Rings by Rhodium(II)-Catalyzed Reactions of Cyclic Diazo Compounds

  • Wang, Xue;Lee, Yong Rok
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1735-1740
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    • 2013
  • Rhodium(II)-catalyzed reactions of cyclic diazo compounds derived from barbituric acid and thiobarbituric acid with a variety of styrene moieties were examined. These reactions provide rapid synthetic routes to the preparations of spirobarbiturates and spirothiobarbiturates bearing cyclopropane rings.

Synchrotron Radiation Induced Photochemical Reactions for Semiconductor Processes

  • Rhee, Shi-Woo
    • Journal of the Korean Vacuum Society
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    • v.3 no.2
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    • pp.147-157
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    • 1994
  • Valence or core electron excitations induced by Synchrotron radiation (SR) irradiation and ensuing chemical reactions can be applied for semiconductor processes i, e, deposition etching and modifications of thin film materials. Unique selectivity can be achieved by this photochemical reactions in deposition and etching. Some materials can be ecvaporated by SR irradiation which can be utilized for low temperature surface cleaning of thin films. Also SR irradiation significantly lowers the reaction temperature and photon activated surface reactions can be utilized for direct writing or projection lithography of electronic materials. This technique is especially effective in making nanoscale feature size with abrupt and well defined interfaces for next generation electronic devices.

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Dipole-Forming Photochemical Group Transfer Reactions of Phthalimides and ${\alpha}-Ketoamides$

  • Yoon, Ung-Chan;Mariano Patrick S.
    • Journal of Photoscience
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    • v.12 no.3
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    • pp.155-162
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    • 2005
  • Results of studies of SET-promoted dipole-forming photochemical group transfer reactions of phthalimide and ${\alpha}-ketoamide$ derivatives are discussed. Azomethine ylide forming photochemical reactions, which are initiated by intramolecular SET from tethered silylmethyl-, carboxymethyl-, and ${\beta}-hydroxyethyl$ containing electron donors to excited states of phthalimides, related maleimides, and conjugated imides, are presented first. Following this, investigations of regioselective 1,4-dipole forming photochemical reactions of N-trialkylsilylmethyl- and N-trialkylstannyl-${\alpha}$-ketoamides are described.

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Spherical Particles Formation in Lubricated Sliding Contact -Micro-explosion due to the Thermally-activated Wear Process-

  • Kwon, O.K.
    • Tribology and Lubricants
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    • v.11 no.5
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    • pp.1-9
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    • 1995
  • The mechanism of various spherical particles formation from wide range of tribo-systerns is suggested and deduced by the action of micro-explosion on the basis of the thermally-activated wear theory, in which the flash temperature at contact could be reached clearly upto the material molten temperature due to the secondary activation energy from the exothermic reactions involving lubricant thermo-decomposition, metals oxidation, hydrogen reactions and other possible complex thermo-reactions at the contacts. Various shapes of spherical particles generated from the tribosystem can be explained by the toroidal action of micro-explosion accompanied with the complex thermo-chemical reactions at the contact surfaces or sub-surfaces.

Rh2(Opiv)4-Catalyzed Reactions of Diazo Compound Derived from Meldrum's Acid and Styrenes. Efficient Synthesis of Cyclopropanes

  • Lee, Yong-Rok;Choi, Jung-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.27 no.4
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    • pp.503-507
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    • 2006
  • The rhodium(II)-catalyzed reactions of diazo compound derived from Meldrum's acid with a variety of styrenes have been examined. These reactions provide a rapid route to the preparation of cyclopropanes with a variety of substituents on the benzene ring. The mechanistic pathway for the formation of these products has been also described in terms of a stepwise mechanism.

Reactions of Thioxanthylium Ion with Organomercurials

  • Shin, Dong-Myung;Kim, Kyong-Tae
    • Bulletin of the Korean Chemical Society
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    • v.2 no.3
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    • pp.114-121
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    • 1981
  • Reactions of thioxanthylium ion with dimethyl-, dibenzyl-, diisopropyl-, and diphenylmercury in the air gave 9,9'-methylenedithioxanthene, 9-benzylthioxanthene, 9-acetonylthioxanthene, and 9-phenylthioxanthene, respectively, as a 9-substituted thioxanthene. In contrast with reactions with aromatics with an electron-donating group, large amount of thioxanthene and thioxanthone were obtained. However, only trace amounts of thioxanthene and thioxanthone were obtained from the reaction with dibenzylmercury under nitrogen atmosphere. In order to explain these reactions, one electron transfer between thioxanthylium ion and organomercurials was proposed.

Reactions in Surfactant Solutions(V): Dephosphorylation of p-Nitrophenyldiphenylphosphinate by Benzimidazole Catalyzed with Ethyltri-n-octylammonium Bromide

  • 홍영석;이정근;김현묵
    • Bulletin of the Korean Chemical Society
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    • v.18 no.12
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    • pp.1260-1264
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    • 1997
  • The phase-transfer reagent (PTC), ethyl tri-n-octylammonium bromide (ETABr), strongly catalyzes the reaction of p-nitrophenyldiphenylphosphinate (p-NPDPIN) with benzimidazole (BI) and its anion (BI-). In ETABr solutions, the dephosphorylation reactions exhibit higer than first order kinetics with respect to the nucleophile, BI, and ETABr, suggesting that reactions are occuring in small aggregates of the three species including the substrate, whereas the reaction of p-NPDPIN with OH- is not catalyzed by ETABr. This behavior for the drastic rate-enhancement of the dephosphorylation is refered as 'aggregation complex model' for reactions of hydrophobic organic phosphinates with benzimidazole in hydrophobic quarternary ammonium salt solutions.

A Review of HLA Genes in Pharmacogenetics: Risk Assessment of Adverse Drug Reactions

  • Yu, Shinae
    • Journal of Interdisciplinary Genomics
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    • v.3 no.1
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    • pp.7-12
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    • 2021
  • Adverse drug reactions (ADRs) is a hypersensitivity reactions to specific medications, and remain a common and major problem in healthcare. ADRs suchc as drug-induced liver injury and life-threatening severe cutaneous adverse drug reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug rash with eosinophilia and systemic symptoms can be occurred by uncontrolled expansion of oligoclonal T cells according to genetically predisposing HLA. In this review, I summarized the alleles of HLA genes which have been proposed to have association with ADRs caused by different drugs.

Histochemical study on the tracheal development in fetuses and neonates of Korean native goats (한국재래산양의 태아 및 신생아 기관의 조직발달에 관한 조직화학적 연구)

  • Kim, Chong-sup
    • Korean Journal of Veterinary Research
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    • v.37 no.2
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    • pp.235-244
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    • 1997
  • The present study was performed to investigate the patterns of appearance of lectin in trachea of fetuses of 60, 90 and 120 days old and neonates of Korean native goat. Carbohydrate markers were used in histochemistry for the determination of the lectin by staining of avidin-biotin-peroxidase complex(ABC), and the markers consisted of biotin-labeled concanavalin A(Con A), dolichos biflorus agglutinin(DBA), rincinus communis agglutinin(RCA-I), ulexeuropalus communis agglutinin(UEA) and wheat germ agglutinin(WGA). 1. The Con A-binding reactions appeared moderately on the apical surface of the tracheal epithelia in 60 days old fetuses, and the reactions were similar on the tracheal epithelia and glands in 90 and 120 days old fetuses and neonates. 2. Reaction of the DBA appeared as the strongest meanwhile the DBA-binding reactions were determined strongly on the apical surface of the tracheal epithelia in the 60 days old fetuses. Reaction for the DBA on the tracheal epithelia and glands of 90 and 120 days old fetuses and neonates were in same manner. 3. The RCA-I-binding reactions appeared very strongly on the apical surface of the tracheal epithelia in 60 and 90 days old fetuses. Reaction to the RCA-1 appeared moderately on certain apical surface of tracheal epithelia and glands in 120 days old fetuses and neonates. 4. No reactions provoked for the UEA in trachea of 60 days old fetuses and neonates, but the UEA-binding reactions appeared moderately in the tracheal epithelia of 90 days old fetuses and weakly in 120 days old fetuses. 5. The WGA-binding reactions appeared very strongly on the apical surface of the tracheal epithelia in 60 and 90 days old fetuses, and moreover, the reactions were determined on the luminal surface of the tracheal gland in 90 days old fetuses. On the other hand, goblet cells of the tracheal epithelia and glands in neonates reacted moderately to the WGA.

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