نتایج جستجو برای: fluorinated analogs

تعداد نتایج: 25458  

Journal: :Organic & biomolecular chemistry 2012
Michel H C J van Houtem Faysal Benaskar Carel F C Fitié Rafael Martín-Rapún Jef A J M Vekemans E W Meijer

The synthesis and self-assembly properties of a fluorinated C(3)-symmetrical 3,3'-bis(acylamino)-2,2'-bipyridine discotic (1) in the mesophase and in solution are described. First, 3,4,5-tris-(1H,1H,2H,2H,3H,3H-perfluoroundecyl-1-oxy)benzoyl chloride was coupled to mono-t-BOC protected 2,2'-bipyridine-3,3'-diamine to afford after deprotection the corresponding fluorinated aromatic amine on a mu...

1997

The use of organofluorine compounds has increased throughout this century, and they are now ubiquitous environmental contaminants. Although generally viewed as recalcitrant because of their lack of chemical reactivity, many fluorinated organics are biologically active. Several questions surround their distribution, fate, and effects. Of particular interest is the fate of perfluoroalkyl substitu...

Journal: :Analytical chemistry 2003
A Marie S Alves F Fournier J C Tabet

Characterization of fluorinated polymers in MALDI is often unsuccessful because commonly used matrixes, such as 2,5-dihydroxybenzoic acid, Indole acrylic acid, alpha-cyano-4-hydroxycinnamic acid, etc., do not desorb/ionize fluorinated polymers efficiently. This could be in part attributed to the unfavorable interaction between the matrix molecules and fluorinated oligomers due to differences in...

2004
Ji-In Jung Jae Young Bae Byeong-Soo Bae

Mesoporous fluorinated organosilicate films were synthesized from tetramethoxysilane and perfluoroalkylsilanes (RO)3Si-R’ [R ~ Me, Et; R’ ~ (CH2)2CF3, (CH2)2(CF2)5CF3, or (CH2)2(CF2)7CF3] under acidic conditions in the presence of cetyltrimethylammonium chloride (CTACl) by sol–gel spin-coating. Calcination at 350 uC allowed the removal of surfactants without destroying the other organic content...

Journal: :Chemical communications 2003
Santos Fustero Esther Salavert Juan F Sanz-Cervera Julio Piera Amparo Asensio

A series of potentially biologically active fluorinated uracil derivatives has been prepared in three steps from oxazolines and fluorinated nitriles with good chemical yields.

Journal: :Organic letters 2016
Mu-Wang Chen Bo Wu Zhang-Pei Chen Lei Shi Yong-Gui Zhou

A highly enantioselective synthesis of chiral fluorinated propargylamines was developed through phosphoric acid and ruthenium-catalyzed chemoselective biomimetic hydrogenation of the carbon-nitrogen double bond of fluorinated alkynyl ketimines in the presence of a carbon-carbon triple bond. This reaction features high chemoselectivity and slow background reaction. In addition, selective transfo...

Journal: :Diagnostics 2014
Farid Menaa Bouzid Menaa Olga N Sharts

Quantitative and qualitative characterization of fluorinated molecules represents an important task. Fluorine-based medicinal chemistry is a fast-growing research area due to the positive impact of fluorine in drug discovery, and clinical and molecular imaging (e.g., magnetic resonance imaging, positron emission tomography). Common detection methods include fluorinated-based labelling using rad...

Journal: :Chemosphere 2014
Martin Scheringer Xenia Trier Ian T Cousins Pim de Voogt Tony Fletcher Zhanyun Wang Thomas F Webster

In this discussion paper, the transition from long-chain poly- and perfluorinated alkyl substances (PFASs) to fluorinated alternatives is addressed. Long-chain PFASs include perfluoroalkyl carboxylic acids (PFCAs) with 7 or more perfluorinated carbons, perfluoroalkyl sulfonic acids (PFSAs) with 6 or more perfluorinated carbons, and their precursors. Because long-chain PFASs have been found to b...

Journal: :Journal of oleo science 2012
Hiromichi Nakahara Osamu Shibata

Over the past two or three decades, Langmuir monolayers comprising various fluorinated amphiphiles such as perfluorinated, partially fluorinated, and fluorinated-hydrogenated hybrid molecules at the air-water interface, have been investigated to deepen the understanding of their characteristic phenomena and to explore the mutual interaction of these amphiphiles with biomembrane constituents. La...

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