Search results for "Alkynes"
showing 10 items of 74 documents
Liver intracellular L-cysteine concentration is maintained after inhibition of the trans-sulfuration pathway by propargylglycine in rats.
1997
To study the fate ofl-cysteine and amino acid homeostasis in liver after the inhibition of the trans-sulfuration pathway, rats were treated with propargylglycine (PPG). At 4 h after the administration of PPG, liver cystathionase (EC4.4.1.1) activity was undetectable,l-cystathionine levels were significantly higher,l-cysteine was unchanged and GSH concentration was significantly lower than values found in livers from control rats injected intraperitoneally with 0.15 M-NaCl. The hepatic levels of amino acids that are intermediates of the urea cycle,l-ornithine,l-citrulline andl-arginine and blood urea were significantly greater. Urea excretion was also higher in PPG-treated rats when compared…
Rapid one-pot propargylamine synthesis by plasmon mediated catalysis with gold nanoparticles on ZnO under ambient conditions
2013
Surface plasmon excitation of gold nanoparticles on ZnO in the presence of an aldehyde, an amine and phenylacetylene led to rapid and selective formation of propargylamines with good yields (50-95%) at room temperature. Plasmon mediated catalysis is the best available route for this ternary coupling.
Toward Photopatternable Thin Film Optical Sensors Utilizing Reactive Polyphenylacetylenes
2013
Substituted polyphenylacetylenes featuring reactive pentafluorophenyl (PFP) ester moieties are synthesized. Parts of the reactive PFP groups are then converted with a mono ortho-nitrobenzyl-protected diamine in variable ratios. Thin films are prepared from these copolymers and irradiated with UV light (λ = 365 nm), resulting in crosslinking of the irradiated areas and hence enabling a photopatterning. We found that during the photocrosslinking process, the excess of PFP ester moieties is stable and remained intact, enabling a subsequent post-polymerization modification step with amines. Noteworthy, this subsequent modification with amines results in a dramatically shift in the UV-vis absorp…
Self-assembly of catalytically-active supramolecular coordination compounds within metal-organic frameworks
2019
[EN] Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal-organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of Pd-II SCCs within the confined space of a pre-formed MOF (SCCs@MOF) and its post-assembly metalation to give a Pd-II-Au-III supra molecular assembly, c…
Efavirenz alters mitochondrial respiratory function in cultured neuron and glial cell lines.
2015
Abstract Background The NNRTI efavirenz is among the most widely employed antiretroviral drugs. Although it is considered safe, efavirenz has been linked with several adverse effects including neurological manifestations, which appear in the majority of the patients on efavirenz-containing regimens. The molecular mechanisms responsible for these manifestations are not understood, but mounting evidence points to altered brain bioenergetics. Methods We evaluated the effect of short-term efavirenz treatment on the mitochondrial respiratory function of cultured glioblastoma and differentiated neuroblastoma cell lines using a Seahorse Extracellular Flux Analyzer. Results Incubation with efaviren…
Lack of mitochondrial toxicity of darunavir, raltegravir and rilpivirine in neurons and hepatocytes: a comparison with efavirenz.
2014
Objectives Growing evidence associates the non-nucleoside reverse transcriptase inhibitor efavirenz with several adverse events. Newer antiretrovirals, such as the integrase inhibitor raltegravir, the non-nucleoside reverse transcriptase inhibitor rilpivirine and the protease inhibitor darunavir, claim to have a better toxicological profile than efavirenz while producing similar levels of efficacy and virological suppression. The objective of this study was to determine the in vitro toxicological profile of these three new antiretrovirals by evaluating their effects on the mitochondrial and cellular parameters altered by efavirenz in hepatocytes and neurons. Methods Hep3B cells and primary …
Efavirenz and the CNS: what we already know and questions that need to be answered
2015
The NNRTI efavirenz has long been one of the most frequently employed antiretroviral drugs in the multidrug regimens used to treat HIV infection, in accordance with its well-demonstrated antiretroviral efficacy and favourable pharmacokinetics. However, growing concern about its adverse effects has sometimes led to efavirenz being replaced by other drugs in the initial treatment selection or to switching of therapy to efavirenz-free regimens in experienced patients. Neurological and neuropsychiatric reactions are the manifestations most frequently experienced by efavirenz-treated patients and range from transitory effects, such as nightmares, dizziness, insomnia, nervousness and lack of conc…
Click chemistry-assisted bioconjugates for hapten immunodiagnostics
2020
Bioorthogonal reactions have revolutionized the way low molecular weight compounds are coupled to biomolecules. Organic chemistry, polymer science, and chemical biology are among the disciplines that are benefited the most from this breakthrough. Despite the reliability of the click chemistry concept for the efficient and chemoselective functionalization of biomacromolecules with haptens at preferred positions, the fact that azide–alkyne cycloaddition reactions originate new chemical moieties as part of the linker may have delayed their application in the immunodiagnostic field. Using the mycotoxin ochratoxin A as a model compound, we herein demonstrate for the first time that bioconjugates…
Hyperpolarized 1H long lived states originating from parahydrogen accessed by rf irradiation
2013
Hyperpolarization has found many applications in Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). However, its usage is still limited to the observation of relatively fast processes because of its short lifetimes. This issue can be circumvented by storing the hyperpolarization in a slowly relaxing singlet state. Symmetrical molecules hyperpolarized by Parahydrogen Induced Hyperpolarization (PHIP) provide a straightforward access to hyperpolarized singlet states because the initial parahydrogen singlet state is preserved at almost any magnetic field strength. In these systems, which show a remarkably long 1H singlet state lifetime of several minutes, the conversion of t…
Stereoselective Synthesis of P-Chirogenic Dibenzophosphole-Boranes via Aryne Intermediates
2012
A new aryne-mediated tandem cross-coupling/P-cyclization sequence starting from tertiary phosphine-boranes and 1,2-dibromobenzenes is reported. P-chirogenic dibenzophospholes become accessible in a regio-, chemo-, and diastereoselective way.