نتایج جستجو برای: fluorinated hydrocarbons
تعداد نتایج: 30992 فیلتر نتایج به سال:
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...
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...
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...
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...
A series of potentially biologically active fluorinated uracil derivatives has been prepared in three steps from oxazolines and fluorinated nitriles with good chemical yields.
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...
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...
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...
The thermodynamics of base pairing is of fundamental importance. Fluorinated base analogs are valuable tools for investigating pairing interactions. To understand the influence of direct base-base interactions in relation to the role of water, pairing free energies between natural nucleobases and fluorinated analogs are estimated by potential of mean force calculations. Compared to pairing of A...
7,12-Dimethylbenz(a)anthnacene (DMBA) and its 1-, 2-, 5-, and 11-fluono derivatives were tested to determine their mutagenicity for ouabain resistance in Chinese hamster V79 cells and their tumor-initiating activity in mouse skin. Inasmuch as V79 cells do not metabolize polycyclic aro matic hydrocarbons, mutagenesis was tested both in the presence and in the absence of golden hamster embryo cel...
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