• 제목/요약/키워드: Fluoro

검색결과 364건 처리시간 0.026초

The Preparation of Alkenyl Fluorides form Organometallic Reagents

  • 이승한;Martin Riediker;Jeffrey Schwartz
    • Bulletin of the Korean Chemical Society
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    • 제19권7호
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    • pp.760-766
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    • 1998
  • Fluorination of alkenyllithium reagents can be accomplished in acceptable yield under conditions which give rise to low competitive alkene formation. These reactions are abetted by the use of the low temperature soluble, mild fluorinating agent N-fluoro-N-tert-butylbenzenesulfonamide; "simpler" fluorinating reagents such as F2, XeF2 or FClO3 failed to give acceptable amounts of the fluoroolefin with these alkenyllithiums.

HCFC-123의 수평 평활관내 응축 전열 특성에 관한 연구 (Condensation Heat Transfer Characteristics of HCFC - 123 inside Horizontal Smooth Tube)

  • 권옥배;오후규;오종택;김성규
    • Journal of Advanced Marine Engineering and Technology
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    • 제17권3호
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    • pp.24-32
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    • 1993
  • Experimental data on the heat transfer characteristics of HCFC-123 and CFC-11 during condensation in horizontal smooth tube are presented. The experimental apparatus consisted of a closed working fluid loop, coolant loop, and measuring system. The major components of the working fluid loop made of a refrigerant pump, boiler, superheater, refrigerant flow meter, receiver and test section. The tube-in-tube type test section was made of smooth tube which were constructed form 9.52 mm outer diameter of smooth copper tube with 50 mm outside diameter of PVC tube duct. The ranges of parameter, such as refrigerant mass velocity, coolant flow rate, and quality were 90-325kg/($m^2$.s), 60-360kg/h, 5-95% respectively. Data were obtained under steady state condition for annular flow. As a result of these, the condensation heat transfer coefficients for HCFC-123 were slightly lower than those of CFC-11 from 8% to 15% inside horizontal smooth tube. Furthermore, a new generalized correlation for the heat transfer coefficients of HCFC-123 and CFC-11 during condensation inside horizontal smooth tube is proposed.

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In vitro Selection of the 2'-Fluoro-2'-Deoxyribonucleotide Decoy RNA Inhibitor of Myasthenic Autoantibodies

  • Seo, Hwa-Seon;Lee, Seong-Wook
    • Journal of Microbiology and Biotechnology
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    • 제10권5호
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    • pp.707-713
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    • 2000
  • Myasthenia gravis (MG) is caused mainly by autoantibodies directed against acetylcholine receptors located in the postsynaptic muscle cell membrane. Using in vitro selection techniques, we isolated an RNA containing 2'-fluoro pyrimidines that can specifically and avidly ($K_d$ ~25 nM) bind rat monoclonal antibody called mAb198, which recognizes the main immunogenic region on the acetylcholine receptors. This RNA can act as a very effective decoy and block mAb198 binding to the receptors in vitro. Furthermore, this RNA decoy can prevent the antigenic modulation of the acetylcholine receptor caused by mAb198 in human muscle cell cultures with and $IC_{50} $of approximately $2.4{\mu}M$. These results indicate that the RNA selected in this study is a more potent decly inhibitor of myashthenic antibodies than the previously identified RNA with 2'-amino pyrimidines [11]. Moreover, this RNA cross-reacts with autoantibodies from patients with MG and can protect human cells from the effects of these antibodies. These observations have important implications for developing an antigen-specific treatment of autoimmune diseases including MG, which is based on decoy RNAs selected in vitro.

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Metabolism and Excretion Study of DW116, A New Fluoroquinolone, in Rats

  • Jung, Byung-Hwa;Park, Young-Han;Park, Jongsei;Chung, Bong-Chul
    • Archives of Pharmacal Research
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    • 제20권4호
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    • pp.358-362
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    • 1997
  • Metabolite identification and urinary and biliary excretion of the new fluoroquinolone antibacterial agent DW116 [1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1 -piperazinyl)-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid, hydrochloride] after oral administration have been studied in Sprague-Dawley rats. The excretion kinetics were monoexponential. Most of the drug was eliminated via the hepatic and renal routes. Mean renal clearance of DW116 was 73.4 ml/hr/kg and mean biliary clearance was 83.8 ml/hr/kg. The major metabolite excreted in the bile was identified as the glucuronide ester of the parent drug using base-hydrolysis of the conjugate metabolite followed by co-HPLC with standard compound, $^{19}$ F-NMR and LC-MS methods. The glucuronide conjugate was also found in urine. The mean urinary recoveries of free and total (free plus glucuronide ester) DW116 were $28.6{\pm}2.7% $and $36.4{\pm}1.8%$ of the administered dose and the corresponding biliary recoveries were $14.4{\pm} 5.5%$ and $37.0{\pm}7.6%$, respectively.

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7-[3-히드록시-(4-메틸티오 또는 4-메틸티오메틸)피롤리디닐]퀴놀린-3-카르복실산의 합성과 항균작용 (Synthesis and Antimicrobial Activity of 7-[3-Hydroxy-(4-methylthio or 4-methylthiomethyl)pyrrolidinyl]quinoline-3-carboxylic Acids)

  • 이재욱;손호정;이규삼;유영효;윤길종
    • 약학회지
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    • 제38권6호
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    • pp.677-682
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    • 1994
  • A number of 7-[3-hydroxy-(4-methylthio or 3-methylthiomethyl)pyrrolidinyl]quinoline-3-carboxylic acids were synthesized by condensation of 7-fluoro substituted quinoline-3-carboxylic acid with 3-hydroxy-4-methylthiopyrrolidine or 3-hydroxy-4-methylthiomethylpyrrolidine. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microorganisms. Among those 1-cyclopropyl-5-amino-6,8-difluoro 7-(3-hydroxy-4-methylthiomethylpyrrolidinyl)-1,4-dihyd ro-4-oxo-3-quinolinecarboxylic acid(12d) and 1-cyclopropyl-6-fluoro-8-methoxy-7-(3-hydroxy-4-methylthiometby1pyrrolinyl)-1,4-dihydro-4-oxo-3-quinolinocarboxylic acid(12g) showed the most potent in vitro antibacterial activity, and 12d showed better antibacterial activity against MRSA compared to ciprofloxacin and sparfloxacin.

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7-[(3-메틸티오 또는 3-메틸티오메틸)피롤리디닐]퀴놀론-3-카르복실산의 합성과 항균작용 (Synthesis and Antimicrobial Activity of 7-[(3-Methylthio or 3-Methylthiomethyl)pyrrolidinyl] quinolone-3-carboxylic Acid)

  • 이재욱;강태충;이규삼;손호정;윤길중;유영효;김대영
    • 약학회지
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    • 제38권2호
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    • pp.197-201
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    • 1994
  • A number of 7-[(3-methylthio or methylthiomethyl)pyrrolidiny]qui nolone-3-carboxylic acids were synthesized by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthiopyrrolidine or 3-methylthiomet hylpyrrolidne. 3-Methylthiopyrrolidine or 3-methylthio-methylpyrrolidine which was prepared from N-benzyl-3-hydroxy pyrrolidine or 3-hydroxymethylpyrrolidine. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microorganisms. Among those 1-cyclopropyl-6,8-difluoro-7-(3-methylthiomethy-lpyrrolidinyl)-1,4-d ihydro-4-oxo-3-quinolinecarboxylic acid(7d) and 1-cyclopropyl-6- fluoro-8-chloro-7-(3-methylthiomethyl pyrrolidinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (7f) showed the most potent in vitro antibacterial activity.

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컨택 산화막 에칭에서의 바닥 모양 찌그러짐 변형 개선 (The Improvement of Profile Tilt in High Aspect Ratio Contact)

  • 황원태;최성길;권상동;임장빈;정상섭;박영욱
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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    • pp.666-670
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    • 2004
  • VLSI 소자에서 design rule(D/R)이 작아져 각 단위 Pattern의 size가 작아짐에 따라 aspect ratio가 커지게 되었다. 산화막 contact etch를 하는데 있어 산화막 측벽을 보호하는데, 이러한 보호막은 주로 fluoro-carbon 계열의 polymer precursor들이 사용된다. Aspect ratio(A/R)가 5 이하일 때에는 측벽의 보호막에 의한 바닥 변형이 문제가 되지 않으나, 10 이상의 A/R를 가진 contact에서는 크기가 줄고, 모양이 불균형하게 변하는 바닥 변형을 쉴게 관찰할 수 있다. 이러한 바닥 변형이 커지면 contact 저항이 높아지는 것은 물론이고, 심하게는 하부 pattern과 overlap 불량을 유발할 수 있다. 본 논문에서는 바닥변형을 일으키는 원인을 분석하고 fluoro-carbon 계열의 polymer precursor의 종류$(C_4_F6\;vs.\;C_3F_8)$에 따른 polymer증착 상태 확인 및 pattern비대칭에 따른 바닥 변형의 고찰과 plasma etching 시 H/W 변형을 통해 바닥 변형이 거의 없는 조건을 찾아낼 수 있었다.

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