• Title/Summary/Keyword: Addition reactions

검색결과 938건 처리시간 0.029초

Indium and Gallium-Mediated Addition Reactions

  • Lee, Phil-Ho
    • Bulletin of the Korean Chemical Society
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    • 제28권1호
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    • pp.17-28
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    • 2007
  • Indium and gallium have emerged as useful metals in organic synthesis as a result of its intriguing chemical properties of reactivity, selectivity, and low toxicity. Although indium belongs to a main metal in group 13, its first ionization potential energy is very low and stable in H2O and O2. Therefore, indium-mediated organic reactions are of our current interest. On the basis of these properties of indium, many efficient indium-mediated organic reactions have been recently developed, such as the addition reactions of allylindium to carbonyl and iminium groups, the indium-mediated synthesis of 2-(2-hydroxyethyl)homoallenylsilanes, the indiummediated allylation of keto esters with allyl halides, sonochemical Reformatsky reaction using indium, the indium-mediated selective introduction of allenyl and propargyl groups at C-4 position of 2-azetidinones, the indium-mediated Michael addition and Hosomi-Sakurai reactions, the indium-mediated β-allylation, β- propargylation and β-allenylation onto α,β-unsaturated ketones, the highly efficient 1,4-addition of 1,3-diesters to conjugated enones by indium and TMSCl, and the intramolecular carboindation reactions. Also, we found gallium-mediated organic reactions such as addition reactions of propargylgallium to carbonyl group and regioselective allylgallation of terminal alkynes.

Analysis of the Korea Food and Drug Administration Adverse Drug Reaction Reports (식품의약품안전청 약물유해반응 보고자료 분석)

  • Rhew, Ki-Yon;Lee, Suk-Hyang
    • Korean Journal of Clinical Pharmacy
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    • 제21권2호
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    • pp.138-144
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    • 2011
  • In order to minimize such adverse drug reactions, governments and international organs have been on the watch for them. Also in South Korea, a system has been established in order that adverse drug reactions may be reported to Korea Food and Drug Administration(KFDA). This study is to analyze drugs to cause adverse reactions, the adverse reactions and patients concerned on the authority of the data of Korea FDA, which is expected to be the preliminary data on preventable adverse reactions. This study was conducted on the 74,037 cases of adverse drug reactions reported to Korea FDA between January 2007 and June 2010. Fentanyl, iopromide and tramadol caused adverse reactions with high frequencies. Oseltamivir showed a high frequency between 2009 and 2010 due to the influence of the new influenza A. Also, OTC drugs accounted for approximately 5% of the adverse reactions. In 2009, adverse drug reactions remarkably increased (2,106 cases; 10.1%) in infants and children due to the new influenza-A(H1N1). The patients aged between 31 and 64 accounted for approximately 55% during the given period. There was no significant intergender difference. In relation to regions, the adverse reactions most frequently occurred in the gastrointestinal system and the integumentary system for three and half years. In addition to anticancer drugs and immunosuppressive drugs that are known to cause adverse reactions frequently, not a few of OTC drugs and external preparations caused such reactions. In particular, the drugs containing specific ingredients caused adverse reactions more frequently than others from 2007 until the first half of 2010. It is advisable for prescribers to acquaint themselves with such adverse reactions and to prescribe drugs other than them. They also have need to sensibly cope with adverse drug reactions just in case they have no substitute drugs. In addition, patients also need to be trained to understand possible adverse reactions in order that they can sensibly accommodate them or choose healthcare services. The results of this study are expected to be helpful to minimize adverse drug reactions.

A comparison of reactions between mothers and fathers to their children's negative emotions (유아의 부정적 정서에 대한 어머니와 아버지의 반응 비교)

  • Lee, Kang-Yi
    • Korean Journal of Human Ecology
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    • 제16권3호
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    • pp.455-463
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    • 2007
  • The purpose of this study was to compare Korean mothers' and fathers' reactions to their children's negative emotions. The survey with questionnaire was performed with 179 mothers and 179 fathers of children aged three to five-years-old from three child care centers in Seoul and Kyoungki Province. Parental emotion-related practices regarding children's negative emotions were assessed with an adaptation of the CCNES-R(Cortes, 2002), and parental reactions were categorized as problem-focused, emotion-focused, expressive encouragement, emotion-teaching, punitive, parental distress and minimizing. The main results were as follows. First, Korean mothers and fathers, in general, used more positive reactions than negative reactions when their children showed negative emotions, in particular problem-focused reactions were mostly used. In addition, Korean mothers were significantly higher than fathers on problem-focused and emotion-teaching reactions. Second, Korean mothers' and fathers' reactions to their children's negative emotions were significantly different depending on the educational level of mothers, mothers' job and fathers' job. But there was no significant differences in parent's reactions according to children's sex and age. The findings in this study provide implication for an association between parent's reactions to children's negative emotions and parent's socioeconomic background.

Extrathermodynamic Relationships for the Nucleophilic Addition Reaction of Mercaptan to a Carbon Double Bond (炭素二重結合에 대한 Mercaptan의 친핵성 첨가 반응의 Extrathermodynamic Relationship에 관한 연구)

  • OK-HYUN PARK;TAE-SUP UHN
    • Journal of the Korean Chemical Society
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    • 제13권4호
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    • pp.297-302
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    • 1969
  • The activation parameters for the nucleophilic addition reactions of n-propyl-, n-butyl-, n-amyl-and n-hexyl-mercaptan to 3, 4-methylene-dioxy-${\beta}$-nitrostyrene were determined at pH 5.8 and pH 2.0, and also the isokinetic temperature of the reactions at pH 5.8 was obtained numerically 262${\circ}$K, and at pH 2.0, 17.1${\circ}$K. From the values obtained above, the fact that the mercaptan having the longer carbon chain has the greater nucleophilicity of it in the addition reactions has been discussed by the extrathermodynamic analysis of ${\Delta}H^{\neq}$and ${\Delta}S^{\neq}$.

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Kinetics Studies on the Mechanism of Hydrolysis of S-Phenyl-S-vinyl-N-p-tosylsulfilimine Derivatives

  • Pyun, Sang-Yong;Kim, Tae-Rin;Lee, Chong-Ryoul;Kim, Whan-Gi
    • Bulletin of the Korean Chemical Society
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    • 제24권3호
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    • pp.306-310
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    • 2003
  • Hydrolysis reactions of S-phenyl-S-vinyl-N-p-tosylsulfilimine (VSI) and its derivatives at various pH have been investigated kinetically. The hydrolysis reactions produced phenylvinylsulfoxide and p-toluene sulfonamide as the products. The reactions are first order and Hammett ρ values for pH 1.0, 6.0, and 11.0 are 0.82, 0.45, and 0.57, respectively. This reaction is not catalyzed by general base. The plot of k vs pH shows that there are three different regions of the rate constants $(k_t)$ in the profile.; At pH < 2 and pH > 10, the rate constants are directly proportional to the concentrations of hydronium and hydroxide ion catalyzed reactions, respectively. The rate constant remains nearly the same at 2 < pH < 10. On the bases of these results, the plausible hydrolysis mechanism and a rate equation have been proposed: At pH < 2.0, the reaction proceeds via the addition of water molecule to sulfur after protonation at the nitrogen atom of the sulfilimine, whereas at pH > 10.0, the reaction proceeds by the addition of hydroxide ion to sulfur directly. In the range of pH 2.0-10.0, the addition of water to sulfur of sulfilimine appears to be the rate controlling step.

The Interactive Effects of Mothers' Reactions and Children's Temperament on 3- to 6-Year-Olds' Aggression

  • Cho, Hye Jung
    • Child Studies in Asia-Pacific Contexts
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    • 제3권2호
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    • pp.139-158
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    • 2013
  • The present study investigated the direct and interactive effects of children's temperament and mothers' reactions to hypothetical vignettes of children's aggression on 3- to 6-year-old children's overt aggression (OA) and relational aggression (RA). A total of 317 mothers of 3- to 6-year-old children and 26 teachers from eight day-care centers and kindergartens were contacted. Each mother reported her child's background, assessed her child's temperament and responded to the Mothers' Reaction to Hypothetical Vignettes of Children's Aggression (MRCA) scale. Children's OA and RA were assessed by teachers. Results showed that high levels of children's surgency predicted children's OA and RA. Although mothers' reactions did not predict children's OA and RA directly, significant interactions indicated that mothers' restrictive reactions were more strongly related to children's OA for children with high levels of surgency and low levels of effortful control. In addition, mothers' responsive reactions were more strongly related to children's OA for children with low levels of surgency. This study demonstrates that relative contributions of children's temperament and mothers' reactions differ according to the form of children's aggression. It also shows that certain types and levels of mothers' reactions to children's aggressive behavior can be critical for children with certain types and levels of temperament in developing children's overt aggression. The findings of this study can be applied to building early prevention and future intervention programs for young children's aggression.

Efficient One-Pot Synthesis of Acridinediones by Indium(III) Triflate-Catalyzed Reactions of β-Enaminones, Aldehydes, and Cyclic 1,3-Dicarbonyls

  • To, Quang Huy;Lee, Yong-Rok;Kim, Sung-Hong
    • Bulletin of the Korean Chemical Society
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    • 제33권4호
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    • pp.1170-1176
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    • 2012
  • An efficient one-pot synthesis of acridinediones by $In(OTf)_3$-catalyzed reactions was developed starting from ${\beta}$-enaminones, aldehydes, and cyclic 1,3-diketones. The key strategies of these reactions involve domino Knoevenagel condensation/Michael addition/cyclodehydration reaction.

Investigation of Temperature Effect on Electrode Reactions of Molten Carbonate Electrolysis Cells and Fuel Cells using Reactant Gas Addition Method

  • Samuel Koomson;Choong-Gon Lee
    • Korean Chemical Engineering Research
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    • 제62권3호
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    • pp.253-261
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    • 2024
  • The impact of temperature on electrode reactions in 100 cm2 molten carbonate cells operating as Fuel Cells (FC) and Electrolysis Cells (EC) was examined using the Reactant Gas Addition (RA) method across a temperature range of 823 to 973 K. The RA findings revealed that introduction of H2 and CO2, reduced the overpotential at Hydrogen Electrode (HE) in both the modes. However, no explicit temperature dependencies were observed. Conversely, adding O2 and CO2 to the Oxygen Electrode (OE) displayed considerable temperature dependencies in FC mode which can be attributed to increased gas solubility due to the electrolyte melting at higher temperatures. In EC mode, there was no observed temperature dependence for overpotential. Furthermore, the addition of O2 led to a decrease in overpotential, while CO2 addition resulted in an increased overpotential, primarily due to changes in the concentration of O2 species.

Reactions of Aryl Organometallic Reagents with Isomers of Phthalonitriles: Triaryl Diketimines and Diketones

  • Lee, Woo-Young;Kim, Young-Soo;Sim, Won-Bo;Park, Chang-Hee;Ahn, Yoon-Mo;Park, Oee-Sook
    • Bulletin of the Korean Chemical Society
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    • 제7권5호
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    • pp.362-366
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    • 1986
  • Synthesis and hydrolysis of aromatic diketimines of triaryl type were investigated by the action of aryl organometallics on the three isomers of phthalonitrile. The reactions of organometallic reagents, prepared from bromobenzene, o-bromotoluene and o-bromoanisol, with iso- and terephthalonitrile proceeded in normal way. Decomposition of the addition complex with dry ammonia, methanol or water gave six diketimines, which could be hydrolysed to the corresponding diketones. Reactions of phthalonitrile with the organometallic reagent were different from the other isomers, so that the decomposition and hydrolysis of the addition complex did not give diimines and the corresponding aromatic diketones.

Theoretical Studies of Solvent Effects on Gas Phase Reactions of Methoxide Ion with Substituted Ethylenes$^\dag$

  • Lee, Ik-Choon;Lee, Bon-Su;Won Jong-Ok
    • Bulletin of the Korean Chemical Society
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    • 제8권6호
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    • pp.444-449
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    • 1987
  • Solvent effects on gas phase reactions of methoxide ion with substituted ethylenes, $CH_2$ = CHR where R = CN, CHO and $NO_2$, are investigated theoretically using the AM1 method. Results show that the methoxide approaches in-plane in all reactions, but subsequently rotate out-of-plane to form tetrahedral complexes in additon reactions. All reactions of a bare methoxide are found to be exothermic, the exothermicity being the greatest in the ${\beta}$-addition, in which the excess energy is forced to be contained within the ${\beta}$-adduct rendering extreme instability. However a part of the excess energy can be removed by a solvate molecule giving a stable complex prior to the product formation. The hydride transfer processes were found to be unfavorable due to the high activation barriers. The ${\alpha}-H^+$ abstraction process from acrylonitrile becomes endothermic as a result of monosolvation of the methoxide, in agreement with experimental results.