Search results for "Organo"

New histone acetylation/deacetylation specific inhibitors: a novel and potential approach to cancer therapy

2011

The acetylation status of histones is regulated in eukaryotes by two kinds of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs), which are responsible for acetylation and deacetylation of lysines residues in N-terminal tails of histone.[1] Thus acetylation, together with phosphorylation and methylation of N-terminal tail of histones, are involved in regulating fundamental processes, such as proliferation and cell death.[2-3] Sodium butyrate, which belongs together with valproic acid to the class of short chain fatty acids, was the first HDAC inhibitor (HDACI) to be identified.[1] Organotin compounds have various influences on physical function including the hormone…

Apoptosis and cell growth arrest in A375 human melanoma cells by diorganotin(IV) and triorganotin(IV) complexes of [meso-Tetra(4-sulfonatophenyl)porp…

2011

In previous studies we have demonstrated that two derivatives of meso-Tetra(4-sulfonatophenyl)porphine (TPPS), (Bu2Sn)2TPPS and (Bu3Sn)4TPPS, cause apoptotic death of A375 melanoma cells and, at lower concentrations, arrest of cell proliferation. In the present study, we examined if the manganese metal inside the porphyrin cavity could improve the efficacy of this class of compounds. Thus, [meso- Tetra(4-sulfonatophenyl)porphine]Mn(III)Cl (=MnTPPS) derivatives, namely (Me2Sn)2MnTPPS, (Bu2Sn)2MnTPPS, (Me3Sn)4MnTPPS and (Bu3Sn)4MnTPPS, were tested on the A375 human melanoma cell line. A cytotoxicity assay showed that (Bu2Sn)2MnTPPS and (Bu3Sn)4MnTPPS were highly cytotoxic by inducing apoptosi…

Sequential Suzuki/Asymmetric Aldol and Suzuki/Knoevenagel Reactions Under Aqueous Conditions

2012

Here we describe for the first time a sequential Suzuki/asymmetric aldol reaction. Such sequential approach was achieved through the combined use of an ionic liquid supported palladium catalyst and the organocatalyst trans-4-(2,2-diphenylacetoxy)proline. Suzuki and asymmetric aldol reactions were performed under aqueous conditions. The use of a palladium catalyst under basic conditions allowed also the first example of sequential Suzuki/Knoevenagel reaction. Reactions were carried out under aqueous conditions and products were isolated in good to high yields and, in the case of the Suzuki/aldol reaction, with diastereoselectivities up to 91:9 and enantioselectivities up to at least 99 %.

Interactions ciment-organofunctional silanes : implications on hydration and on mechanical properties of the modified systems

2010

Nowadays concrete is the most attractive option for the construction sector. This is because concrete itself is a low cost, low energy and low environmental impact material. Moreover, concrete structures are very durable and high load bearing. This is achieved by incorporating steel, because concrete itself is a very low tensile strength material. Chemically, the weakness originates in the cohesive nature of cement used for concrete making. Nanoscale experimental investigations and numerical simulations showed that cohesion of cement paste is caused by short range surface forces acting between calcium silicate hydrates (C-S-H) in the interstitial solution. This thesis addresses the possibil…

Chemistry of ?-hydridobis[pentacarbonylchromium(0)] species. Part III. Redox reactions with mercury(II) compounds and iodine

1981

[Cr2(CO)10(μ-H)]− undergoes ready hydride substitution on reaction with HgX2 (X = Cl, Br, I or SCN) or with iodine in acetone, yielding [Cr2(CO)10(μ-X)]− complex species which can be converted quantitatively into [Cr(CO)5X]− anions by reactions conducted in the presence of an excess of X−.

Chemical Aspects of Human and Environmental Overload with Fluorine

2021

Over the last 100-120 years, due to the ever-increasing importance of fluorine-containing compounds in modern technology and daily life, the explosive development of the fluorochemical industry led to an enormous increase of emission of fluoride ions into the biosphere. This made it more and more important to understand the biological activities, metabolism, degradation, and possible environmental hazards of such substances. This comprehensive and critical review focuses on the effects of fluoride ions and organofluorine compounds (mainly pharmaceuticals and agrochemicals) on human health and the environment. To give a better overview, various connected topics are also discussed: reasons an…

Dual Hydrogen Bond - Enamine Catalysis Enables a Direct Enantioselective Three-Component Domino Reaction

2011

A dual system, composed of an enantioselective enamine catalyst and a multiple-hydrogen-bond catalyst achieves the three-component enantioselective aldehyde—nitroalkene—aldehyde domino reaction using either two similar or two different aldehydes.

Enantioselective Strecker Reaction Catalyzed by an Organocatalyst Lacking a Hydrogen-Bond-Donor Function

2007

Hydrogen-ion driven molecular motions in Cu2+-complexes of a ditopic phenanthrolinophane ligand

2004

One of the first kinetic evaluations of a metal ion interchange between the two coordination sites of a ditopic macrocycle is presented. Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es ; Soriano Soto, Concepción, Concepcion.Soriano@uv.es ; Verdejo Viu, Begoña, Begona.Verdejo@uv.es

Structural reorganization in a hydrogen-bonded organic framework

2018

Self-recognition of 3,3′,5,5′-azobenzenetetracarboxylic acid drives the formation of a grid-like anionic hydrogen-bonded framework with channels occupied by organic cations. This supramolecular solid is capable of reorganizing its connectivity in the presence of specific guests into a different crystalline architecture by sequential dissolution and recrystallization.