• Title/Summary/Keyword: ortho-fluorination

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A Novel Aromatic Fluorine-18 Labeling Method Using Iodonium Salts Precursor (이오도늄 솔트 전구체를 이용한 새로운 방향족 화합물 플루오린-18 표지 기술)

  • Moon, Byung-Seok;Lee, Byung-Chul;Kim, Sang-Eun
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.1
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    • pp.1-9
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    • 2009
  • As many new drug substances contained various aromatic rings and fluorine attached to an electron rich aromatic ring or on the meta-position, a strategy towards improvement in aromatic fluorination of these compounds is highly desirable. The introduction of fluorine-18 onto aromatic rings showed in the limited condition containing electron withdrawing group (EWG) on the para- or ortho-position to get reasonable radiochemical yield so far. No-carrier added (NCA) [$^{18}F$]fluoroarene syntheses by iodonium salts recently reported that has the potential to greatly increase the yield in systems or positions that normally not reactive enough to give sufficient yields in simple model reaction. This review describes the methodological approach towards effective aromatic fluorination by diaryliodonium salts and future prospects in an application of novel PET radiotracer.

Recent Liquid Crystal Material Development for VA-TFT

  • Bremer, Matthias
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1067-1070
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    • 2005
  • A large size flat panel LCD-TV must fulfill different requirements than a desktop LCD-monitor: The contrast must be much larger, the viewing angle should be as wide as possible and the switching times must be shorter to allow moving pictures to be displayed naturally. The "Vertically Aligned" technology is most promising to realize such a product. LC-material development for this technology began at Merck about 10 years ago. New materials based on the 1,1,6,7-tetrafluoroindane skeleton were recently synthesized via ortho-metallation and intramolecular Heck cyclization followed by an oxidative fluorination procedure. The materials offer improved properties over liquid crystals currently employed in flat panel LCD-TVs.

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