Search results for "TRIF"
showing 10 items of 1419 documents
Tandem Nucleophilic Addition−Intramolecular Aza-Michael Reaction: Facile Synthesis of Chiral Fluorinated Isoindolines
2010
A highly stereoselective synthesis of fluorinated 1,3-disubstituted isoindolines is described. To this end, a tandem reaction consisting of a diastereoselective addition of fluorinated nucleophiles to Ellman's N-(tert-butanesulfinyl)imines followed by an intramolecular aza-Michael reaction has been developed. This strategy allows for the construction of isoindolines bearing several degrees of fluorination (mono-, di-, or trifluoromethyl as well as heavier fluorinated groups). In the majority of all cases, the products are formed as single isomers.
Design, synthesis, and biological evaluation of nonsteroidal cycloalkane[d]isoxazole-containing androgen receptor modulators.
2012
We report here the design, preparation, and systematic evaluation of a novel cycloalkane[d]isoxazole pharmacophoric fragment-containing androgen receptor (AR) modulators. Cycloalkane[d]isoxazoles form new core structures that interact with the hydrophobic region of the AR ligand-binding domain. To systematize and rationalize the structure-activity relationship of the new fragment, we used molecular modeling to design a molecular library containing over 40 cycloalkane[d]isoxazole derivatives. The most potent compound, 4-(3a,4,5,6,7,7a-hexahydrobenzo[d]isoxazol-3-yl)-2-(trifluoromethyl)benzonitrile (6a), exhibits antiandrogenic activity significantly greater than that of the most widely used …
Morphology of hybrid polystyrene-block-poly(ethylene oxide) micelles: Analytical ultracentrifugation and SANS studies
2006
Abstract Morphology and structure of aqueous block copolymer solutions based on polystyrene- block -poly(ethylene oxide) (PS- b -PEO) of two different compositions, a cationic surfactant, cetyl pyridinium chloride (CPC), and either platinic acid (H 2 PtCl 6 ⋅6H 2 O) or Pt nanoparticles were studied using a combination of analytical ultracentrifugation (AUC), transmission electron microscopy (TEM), and small angle neutron scattering (SANS). These studies combining methods contributing supplemental and analogous structural information allowed us to comprehensively characterize the complex hybrid systems and to discover an isotope effect when H 2 O was replaced with D 2 O. In particular, TEM s…
(Trifluoromethoxy)Phenylboronic Acids: Structures, Properties, and Antibacterial Activity.
2021
Three isomers of (trifluoromethoxy)phenylboronic acids were studied in the context of their physicochemical, structural, antimicrobial and spectroscopic properties. They were characterized by 1H, 13C, 11B and 19F NMR spectroscopy. The acidity of all the isomers was evaluated by both spectrophotometric and potentiometric titrations. The introduction of the -OCF3 group influences the acidity, depending, however, on the position of a substituent, with the ortho isomer being the least acidic. Molecular and crystal structures of ortho and para isomers were determined by the single crystal XRD method. Hydrogen bonded dimers are the basic structural motives of the investigated molecules in the sol…
Phosphonic Acid Analogs of Fluorophenylalanines as Inhibitors of Human and Porcine Aminopeptidases N: Validation of the Importance of the Substitutio…
2020
International audience; A library of phosphonic acid analogs of phenylalanine substituted with fluorine, chlorine and trifluoromethyl moieties on the aromatic ring was synthesized and evaluated for inhibitory activity against human (hAPN) and porcine (pAPN) aminopeptidases. Fluorogenic screening indicated that these analogs are micromolar or submicromolar inhibitors, both enzymes being more active against hAPN. In order to better understand the mode of the action of the most active compounds, molecular modeling was used. It confirmed that aminophosphonic portion of the enzyme is bound nearly identically in the case of all the studied compounds, whereas the difference in activity results fro…
Crystal Structure of Human Filamin C Domain 23 and Small Angle Scattering Model for Filamin C 23–24 Dimer
2007
Filamin C is a dimeric, actin-binding protein involved in organization of cortical cytoskeleton and of the sarcomere. We performed crystallographic, small-angle X-ray scattering and analytical ultracentrifugation experiments on the constructs containing carboxy-terminal domains of the protein (domains 23-24 and 19-21). The crystal structure of domain 23 of filamin C showed that the protein adopts the expected immunoglobulin (Ig)-like fold. Small-angle X-ray scattering experiments performed on filamin C tandem Ig-like domains 23 and 24 reveal a dimer that is formed by domain 24 and that domain 23 has little interactions with itself or with domain 24, while the analytical ultracentrifugation …
Cockroach allergens Per a 3 are oligomers
2009
Allergens from cockroaches cause major asthma-related health problems worldwide. Among them Per a 3 belongs to the most potent allergens. Although the sequences of some members of the Per a 3-family are known, their biochemical and biophysical properties have not been investigated. Here we present for the first time a thorough structural characterization of these allergens, which have recently been tested to induce an increase of allergy specific indicators in blood of Europeans. We isolated two Per a 3 isoforms, which occur freely dissolved in the hemolymph as hexamers with molecular masses of 465+/-25kDa (P II) and 512+/-25kDa (P I). Their sedimentation coefficients (S(20,W)) were determi…
Experimental and Computational Studies of Hydrogen Bonding and Proton Transfer to [Cp*Fe(dppe)H]
2005
The present contribution reports experimental and computational investigations of the interaction between [Cp*Fe(dppe)H] and different proton donors (HA). The focus is on the structure of the proton transfer intermediates and on the potential energy surface of the proton transfer leading to the dihydrogen complex [Cp*Fe(dppe)(H2)]+. With p-nitrophenol (PNP) a UV/Visible study provides evidence of the formation of the ion-pair stabilized by a hydrogen bond between the nonclassical cation [Cp*Fe(dppe)(H2)]+ and the homoconjugated anion ([AHA]-). With trifluoroacetic acid (TFA), the hydrogen-bonded ion pair containing the simple conjugate base (A-) in equilibrium with the free ions is observed…
Biochemical characterization and ligand binding properties of neuroglobin, a novel member of the globin family.
2001
Neuroglobin is a recently discovered member of the globin superfamily that is suggested to enhance the O(2) supply of the vertebrate brain. Spectral measurements with human and mouse recombinant neuroglobin provide evidence for a hexacoordinated deoxy ferrous (Fe(2+)) form, indicating a His-Fe(2+)-His binding scheme. O(2) or CO can displace the endogenous protein ligand, which is identified as the distal histidine by mutagenesis. The ferric (Fe(3+)) form of neuroglobin is also hexacoordinated with the protein ligand E7-His and does not exhibit pH dependence. Flash photolysis studies show a high recombination rate (k(on)) and a slow dissociation rate (k(off)) for both O(2) and CO, indicating…
Divulging the various chemical reactivity of trifluoromethyl-4-vinyl-benzene as well as methyl-4-vinyl-benzene in [3+2] cycloaddition reactions.
2020
Abstract In the present paper, an investigation about the [3 + 2]cycloaddition (32 C A) reactions of benzonitrile oxide with 1-trifluoromethyl-4-vinyl-benzene, and with 1-methyl-4-vinyl-benzene, using the Molecular Electron Density Theory (MEDT) through DFT/B3LYP/6–311++G (d,p), is performed. A deep mechanistic study beside an accurate electronic description of different stationary points along the IRC paths of the two 32 C A reactions have performed by examining the two competitive regioisomericortho/metareaction pathways, and providing the mechanism associated with them. The presence of the CF3 group reduces the activation energy, which makes it possible to increase the experimental yield…