نتایج جستجو برای: fluorination treatment

تعداد نتایج: 1395580  

2012
Valery N. Khabashesku

Ando, et a!., Direct interaction of elemental fluorine with diamond surfaces, Diamond and Related Materials 1996; 5: 1021-1025.* Kealey, et a!., Fluorination of polycrystalline diamond films and powders. An investigation using FTIR spectroscopy, SEM, energyfiltered TEM, XPS and fluorine-IS radiotracer methods, J. Mater. Chern. 2001; 11: 879-886.* Liu, et a!., Functionalization of Nanoscale Diam...

Journal: :Chemistry & biology 2008
Guy Eelen Noelia Valle Yoshiteru Sato Natacha Rochel Lieve Verlinden Pierre De Clercq Dino Moras Roger Bouillon Alberto Muñoz Annemieke Verstuyf

Side chain fluorination is often used to make analogs of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] resistant to degradation by 24-hydroxylase. The fluorinated nonsteroidal analogs CD578, WU515, and WY1113 have an increased prodifferentiating action on SW480-ADH colon cancer cells, which correlated with stronger induction of vitamin D receptor (VDR)-coactivator interactions and stronger repression ...

Journal: :Journal of the American Chemical Society 2011
Jeremy Erb Daniel H Paull Travis Dudding Lee Belding Thomas Lectka

We report in full detail our studies on the catalytic, asymmetric α-fluorination of acid chlorides, a practical method that produces an array of α-fluorocarboxylic acid derivatives in which improved yield and virtually complete enantioselectivity are controlled through electrophilic fluorination of a ketene enolate intermediate. We discovered, for the first time, that a third catalyst, a Lewis ...

Journal: :Organic Process Research & Development 2021

Hydrogen bonding phase-transfer catalysis offers a convenient solution to activate safe and economical metal alkali fluorides for enantioselective nucleophilic fluorination. Herein, we demonstrate the scalability of this protocol with fluorination 200 g racemic trans-N,N-dibenzyl-2-bromocyclohexan-1-amine in mechanically stirred 1 L glass reactor using 0.5 mol % bis-urea organocatalyst. In thes...

Journal: :IEEE Transactions on Dielectrics and Electrical Insulation 2022

This article investigates the surface electrical properties of polyether-ether-ketone (PEEK) and cross-linked polyethylene (XLPE) before after fluorination modification. The samples are tested for conductivity, morphology, antiaging characteristics. also flashover voltage with ramping under 100, 20, 10 kPa. results showed that surfaces PEEK XLPE become slightly smoother increase in time conduct...

2011
Lukas Hintermann Mauro Perseghini Antonio Togni

Titanium-based Lewis acids catalyze the α-fluorination of β-ketoesters by electrophilic N-F-fluorinating reagents. Asymmetric catalysis with TADDOLato-titanium(IV) dichloride (TADDOL = α,α,α',α'-tetraaryl-(1,3-dioxolane-4,5-diyl)-dimethanol) Lewis acids produces enantiomerically enriched α-fluorinated β-ketoesters in up to 91% enantiomeric excess, with either F-TEDA (1-chloromethyl-4-fluoro-1,4...

Journal: :Organic & biomolecular chemistry 2012
Yan Li Kraig A Wheeler Roman Dembinski

Synthesis of highly substituted 3-fluorofurans is reported. The sequence began with preparation of tert-butyldimethylsilyl alk-1-en-3-yn-1-yl ethers from 1,4-disubstituted alk-3-yn-1-ones. Subsequent fluorination of alkenynyl silyl ethers with Selectfluor gave 2-fluoroalk-3-yn-1-ones in almost quantitative yield. Subsequent 5-endo-dig cyclizations using chlorotriphenylphosphine gold(I)/silver t...

2001
S. R. Sheng W. R. McKinnon S. P. McAlister C. Storey J. S. Hamel P. Ashburn

The effects of fluorine on the hot-carrier induced degradation in low-thermal-budget polysilicon-emitter NPN bipolar transistors have been examined. Forward Gummel plots, base-emitter (BE) diode characteristics, and stress currents were measured during reverse BE bias stress. Fluorinated devices behave similarly under stress to nonfluorinated devices retaining the initial improvement observed i...

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