نتایج جستجو برای: fluorination
تعداد نتایج: 1361 فیلتر نتایج به سال:
The outstanding characteristics of fluorine gas, e.g. extreme reactivity and oxidizing power, and the utmost electronegativity of F ion, lead to very strong bonds between fluorine and most of the other elements of the periodical table. Treatments involving F2, fluorinated gases and rf plasma-enhanced fluorination (PEF) constitute exceptional tools for modifying the surface properties of materia...
In this work, typical high-performance yarns are oxy-fluorinated, such as carbon fibers, ultra-high-molecular-weight polyethylene, poly(p-phenylene sulfide) and poly(p-phenylene terephthalamide). The focus is on the property changes of the fiber surface, especially the wetting behavior, structure and chemical composition. Therefore, contact angle, XPS and tensile strength measurements are perfo...
PR04.MZ 8-(4-fluoro-but-2-ynyl)-3-p-tolyl-8-aza-bicyclo[3.2.1]octane-2-carboxylic acid methyl ester (1) and LBT999 8-((E)-4-fluoro-but-2-enyl)-3b-p-tolyl-8-aza-bicyclo[3.2.1]octane-2beta-carboxylic acid methyl ester (2) are selective dopamine reuptake inhibitors, derived from cocaine. Compounds 1 and 2 were labelled with fluorine-18 at their terminally fluorinated N-substituents employing micro...
A low-pressure plasma surface treatment of polymeric powders was carried out in a circulating fluidized bed (CFB) reactor (10 mm-I.D. × 800 mm-high) with CF4 glow discharge. The effects of solid circulation rate, treatment time and radio frequency (rf) power of plasma on fluorination of high-density polyethylene (HDPE) powders have been determined. X-ray photoelectron spectroscopy (XPS) and the...
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...
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 ...
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 ...
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...
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