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showing 10 items of 607 documents
Anaerobic Palladium-Catalyzed Chemoselective Oxidation of Allylic and Benzylic Alcohols with α-Bromo Sulfoxide as a Co-Oxidant.
2007
A chemoselective palladium-catalyzed anaerobic oxidation of allylic and benzylic alcohols using an α-bromo sulfoxide as a co-oxidant is described for the first time. The catalyst system is simple and has a long life because of the allowance of phosphane ligands under the non-aerobic conditions. The advantages of the described method include no overoxidation of primary alcohols to carboxylic acids because of the mild conditions applied, the tolerance of oxygen-sensitive functionalities such as a carbon-carbon double bond, an organothio group, or a diorganoamino group and the effective preparation of α,β-unsaturated aldehydes and ketones, resulting from the oxidation of primary and secondary …
Chlorido(dimethyl sulfoxide)(pyridine-2-thiolato N-oxide-κ2S,O)platinum(II)
2008
The asymmetric unit of the title compound, [Pt(C5H4NOS)Cl(C2H6OS)], contains two independent complex molecules having similar geometries. Each PtII atom is four-coordinated in a distorted square-planar geometry by S and O atoms of one pyridine N-oxide ligand, the S atom of one dimethyl sulfoxide molecule and one terminal Cl− ion. The molecules are linked into a three-dimensional framework by C—H...O and C—H...Cl hydrogen bonds.
Environmental analysis of chlorinated aromatic thioethers, sulphoxides and sulphones
1993
Abstract Chlorinated aromatic thioethers discussed here are polychlorinated dibenzothiophenes, thianthrenes and diphenylsulphides. Relatively little is known about their occurrence, behaviour and fate in the environment. Polychlorinated dibenzothiophenes and diphenylsulphides have recently been found to be formed in waste combustion and analysed in pulp mill effluents. Chlorinated sulphoxides and sulphones are usually metabolites or oxidation products of different chlorinated aromatic compounds. Different gas chromatographic-mass spectrometric techniques are used in the analysis of the chlorinated thioethers. The sulphoxides and sulphones, because of their higher polarity, can be isolated f…
New acetylenes fromChrysanthemum coronarium L.
1990
The investigation of the aerial parts of Chrysanthemum coronarium yielded, in addition to several known compounds, two new acetylenic sulfoxides 9 and 10, and a new thiophene spiroacetal enol ether 11. Their structures were deduced by spectroscopic and chemical methods.
Coping with Oxygen
2010
Sometime before 2.7 BYA, a new and biologically toxic substance began to appear in the environment. Biologically produced dioxygen, O2, probably first began to accumulate in small pools or layers above cyanobacterial mats. These photosynthesizers must have already developed ways to at least partially deal with dioxygen and, with greater difficulty, the reactive oxygen species (ROS) derived from it (see Chap. 1 and below). But for primitive anaerobes in the vicinity, these new substances must have been especially toxic. Nevertheless, it is clear that they evolved ways to cope with the new threats. One way was to simply avoid dioxygen altogether.
Conformational stability of oligoferrocene oligoamide foldamers
2016
Abstract Organometallic oligoamides built from three to four ferrocene amino acid units ( H-Fca-OH , 1-amino-1′-ferrocene carboxylic acid) fold into hydrogen bonded secondary structures featuring eight-membered rings by cooperative hydrogen bonds. NMR studies and DFT calculations (CAM-B3LYP, LANL2DZ, IEFPCM (THF)) reveal that the organometallic zigzag foldamer structures are highly resistant toward denaturation by hydrogen bond acceptors such as dimethyl sulfoxide and 2,4-lutidine. Replacing one ferrocene amino acid unit by the organic α -amino acid glycine at the C -terminal end (Fca → Gly) significantly destabilizes the secondary zigzag structure facilitating denaturation by DMSO. Highly …
Inhibitoren der Korrosion 23 (1) - Gibt es eine Struktur- Wirkungs-Beziehung bei organischen Inhibitoren der Korrosion von Aluminium?
1978
Uber 400 organische Verbindungen wurden routinemasig darauf gepruft, ob sie die Auflosung des Aluminiums in In Salzsaure in Gegenwart von 2,5% NaCl und bei einer Konzentration von 10−2 Mol/l der zu prufenden Verbindung beeinflussen. Es wurde versucht, eine “Struktur-Wirkungs-Beziehung” zu erstellen. Eingehender diskutiert wurden folgende Verbindungsklassen: Arsenverbindungen, Phosphon- und Phosphinsauren, aromatische Aldehyde und Ketone, aromatische und aliphatische Carbonsauren, zweiwertige Phenole, Tetrazoliumsalze und formazane, Sulfoxide und aromatische Sulfonsauren, Sulfonamide und Sulfone. Bei einer Auswahl von Inhibitoren wurde die Abhangigkeit der Schutzwirkung von deren Konzentrati…
The effect of free polymer on the interactions and the glass transition dynamics of microgel colloids.
2002
By studying the phase behaviour and the short range order of polystyrene microgel colloids in a good solvent we demonstrated that these particles can be considered as hard spheres or nearly hard spheres if the internal cross link density is made sufficiently high. A binary mixture of 1:50 crosslinked (1 crosslink per 50 monomers) particles with a size ratio R(small)/R(large) = 0.83 and a number ratio N(small)/N(large) = 2.7 was characterized with respect to the short range order and glass transition dynamics. We found that this mixture can be mapped onto a one-component hard sphere system with an effective polydispersity of 11%, even though for the particle interactions an inverse power pot…
Tandem asymmetric Michael reaction-intramolecular Michael addition. An easy entry to chiral fluorinated 1,4-dihydropyridines.
2010
A novel one-pot tandem asymmetric Hantzsch-type process has been employed to generate fluorinated 1,4-dihydropyridines (1,4-DHPs) as single diastereoisomers. It involves the condensation of (R)-(+)-allyl p-tolyl sulfoxide, fluorinated nitriles, and alkyl propiolates, giving access to a new family of enantiomerically pure fluorine-containing 1,4-DHPs.
The immunosuppressive enzyme IL4I1 promotes FoxP3+regulatory T lymphocyte differentiation
2015
Abstract IL4I1 (interleukin-4-induced gene 1) is a phenylalanine oxidase produced mainly by APCs of myeloid origin, and converts phenylalanine (Phe) to phenylpyruvate, hydrogen peroxide, and ammonia. We have previously shown that IL4I1 is highly expressed by tumor-associated macrophages from various human cancers and facilitates immune evasion from the cytotoxic response in a murine tumor model. Indeed, IL4I1 inhibits T-cell proliferation via hydrogen peroxide toxicity on effector/memory T cells. Here, we explored the effect of IL4I1 on naive CD4(+) T-cell differentiation. We show that IL4I1 stimulates the generation of Foxp3(+) regulatory T (Treg) cells in vitro from human and mouse T cell…