Search results for "CARBONYLATION"

Heterodimer formation of wild-type and amyotrophic lateral sclerosis-causing mutant Cu/Zn-superoxide dismutase induces toxicity independent of protei…

2008

Recent studies provide evidence that wild-type Cu/Zn-superoxide dismutase (SOD1(hWT)) might be an important factor in mutant SOD1-mediated amyotrophic lateral sclerosis (ALS). In order to investigate its functional role in the pathogenesis of ALS, we designed fusion proteins of two SOD1 monomers linked by a polypeptide. We demonstrated that wild-type-like mutants, but not SOD1(G85R) homodimers, as well as mutant heterodimers including SOD1(G85R)-SOD1(hWT) display dismutase activity. Mutant homodimers showed an increased aggregation compared with the corresponding heterodimers in cell cultures and transgenic Caenorhabditis elegans, although SOD1(G85R) heterodimers are more toxic in functiona…

ChemInform Abstract: Preparation and Application of Iron-Substituted (Z)-Enals: Synthesis of 5-Substituted α,β-Butenolides.

2001

The role of distannoxanes in the synthesis of dimethyl carbonate from carbon dioxide

2003

Abstract The synthesis, characterization, and reactivity of 1,3-dimethoxytetrabutyldistannoxane were investigated in connection to the mechanism of the selective synthesis of dimethyl carbonate from CO2 and methanol. A new distannoxane, 1-methoxy-3-methylcarbonatotetrabutyldistannoxane, resulting from a 1:1 adduct with CO2 was isolated and characterised by volumetry, multinuclear NMR and IR spectroscopies. When this compound was submitted to 20 MPa of CO2 at 423 K in toluene no dimethyl carbonate was formed, conversely to dibutyldimethoxystannane. However, when methanol was the solvent, dimethyl carbonate was selectively produced. A promoting effect of Si(OCH3)4 was evidenced through methox…

ChemInform Abstract: Switchable Palladium-Catalyst Reaction of Bromomethyl Sulfoxides, CO, and N-Nucleophiles: Aminocarbonylation at Csp3versus Oxida…

2013

Pd2(dba)3/ Xantphos-catalyzed coupling of the sulfoxides (I) and (V) with amines and carbon monoxide allows a new and efficient access to amides of type (IV) and (VI).

Role of glutathione in cell nucleus

2010

Cells with high proliferation rate have high glutathione levels. This typical feature of cancer cells is viewed usually as a defence mechanism against ionizing radiation or chemotherapy. Efforts have been made in order to decrease cellular glutathione levels in tumours as a necessary pre-treatment for cancer therapy. However, very few reports have considered cellular glutathione as a physiological tool for cells to proliferate and that most of this high glutathione levels were located in the nucleus. The role of nuclear glutathione in cell physiology has become more important in the last years. This review summarizes new findings that point to the nuclear reduced status as an environment th…

Histone carbonylation occurs in proliferating cells

2012

12 páginas, 10 figuras (que no es encuentran en este documento, se pueden ver en: http://www.sciencedirect.com/science/article/pii/S0891584912000664)

Multiple Roles of Isocyanides in Palladium-Catalyzed Imidoylative Couplings: A Mechanistic Study

2016

International audience; Kinetic, spectroscopic and computational studies examining a palladium-catalyzed imidoylative coupling highlight the dual role of isocyanides as both substrates and ligands for this class of transformations. The synthesis of secondary amides from aryl halides and water is presented as a case study. The kinetics of the oxidative addition of ArI with RNC-ligated Pd-0 species have been studied and the resulting imidoyl complex [(ArC=NR)Pd(CNR)(2)I] (Ar=4-F-C6H4, R = tBu) has been isolated and characterized by X-ray diffraction. The unprecedented ability of this RNC-ligated imidoyl-Pd complex to undergo reductive elimination at room temperature to give the amide in the p…

Theoretical and structural studies of lithium cyclic amide conformations. Monomers and aggregates

2000

High level ab initio calculations on the conformations of unsolvated and solvated lithium piperidide, 1, and lithium morpholide, 2, were carried out. It was found that both monomers exhibit a global minimum for a chair structure with a planar nitrogen, and 2 shows an additional stable pseudo boat conformation. Dimers and amine–lithium amide mixed aggregates were also calculated including discrete solvation; the role of aggregation is clearly shown both by the changes in geometries and in the stabilization energies. Semiempirical calculations carried out on a recently synthesized tetrameric mixed aggregate give a geometry very similar to the structure determined by X-ray diffraction. The pre…

Cyclocarbonylation reactions of allylphenols and allylnaphthols catalyzed by Pd/C- 1,4-bis(diphenylphosphine)butane

2002

Palladium/activated carbon (Pd/C) in the presence of 1,4-bis(diphenylphosphino)butane is an efficient heterogeneous catalyst for cyclocarbonylation reactions of 2-allyl phenols affording five-, six-, and seven-membered ring lactones. Various examples of cyclocarbonylation are reported and the regioselectivity is compared with the homogeneous system. Both commercial Pd/C and Pd/C prepared from activated carbons obtained from vegetable and polymeric wastes are investigated.

Ethylene polymerization catalysts based on nickel(II) 1,4-diazadiene complexes: the influence of the 1,4-diazadiene backbone substituents on structur…

1998

Abstract Thermally sensitive dialkyl nickel complexes {DAD(H,H)}Ni(CH2SiMe3)2 and {DAD(Me,Me)}Ni(CH2SiMe3)2 [DAD(X,X)=2,6-iPr2C6H4–NC(X)–C(X)N–C6H4iPr2-2,6] were synthesized and were characterized by X-ray diffraction studies on single crystals. The substituents X on the backbone of the α-diimine ligand significantly influence the conformation of the 2,6-diisopropylphenyl substituents. This effect is thought to be of crucial importance for the polymerization of ethylene when {DAD(X,X)}NiBr2/MAO is used as catalyst. The influence of the catalyst structure, pressure, and temperature on the polymerization activity, molar mass, glass transition temperature, melting temperature and branching o…