Search results for "Pyridine"
showing 10 items of 2516 documents
Chromo-Fluorogenic Detection of Nitroaromatic Explosives by Using Silica Mesoporous Supports Gated with Tetrathiafulvalene Derivatives
2013
[EN] Three new hybrid gated mesoporous materials (SN3-1, SNH2-2, and SN3-3) loaded with the dye [Ru(bipy)(3)](2+) (bipy=bipyridine) and capped with different tetrathiafulvalene (TTF) derivatives (having different sizes and shapes and incorporating different numbers of sulfur atoms) have been prepared. The materials SN3-1 and SN3-3 are functionalized on their external surfaces with the TTF derivatives 1 and 3, respectively, which were attached by employing the click chemistry reaction, whereas SNH2-2 incorporates the TTF derivative 2, which was anchored to the solid through an amidation reaction. The final gated materials have been characterized by standard techniques. Suspensions of these s…
Structural Determinants for the Mode of Action of Imidazopyridine DS2 at δ-Containing γ-Aminobutyric Acid Type A Receptors
2021
Despite the therapeutic relevance of δ-containing γ-aminobutyric acid type A receptors (GABAARs) and the need for δ-selective compounds, the structural determinants for the mode and molecular site of action of δ-selective positive allosteric modulator imidazo[1,2-a]pyridine DS2 remain elusive. To guide the quest for insight, we synthesized a series of DS2 analogues guided by a structural receptor model. Using a fluorescence-based fluorometric imaging plate reader membrane potential assay, we found that the δ-selectivity and the pharmacological profile are severely affected by substituents in the 5-position of the imidazopyridine core scaffold. Interestingly, the 5-methyl, 5-bromo, and 5-chl…
Inhibition of the Cysteine Protease Human Cathepsin L by Triazine Nitriles: Amide⋅⋅⋅Heteroarene π-Stacking Interactions and Chalcogen Bonding in the …
2016
We report an extensive "heteroarene scan" of triazine nitrile ligands of the cysteine protease human cathepsin L (hCatL) to investigate π-stacking on the peptide amide bond Gly67-Gly68 at the entrance of the S3 pocket. This heteroarene⋅⋅⋅peptide bond stacking was supported by a co-crystal structure of an imidazopyridine ligand with hCatL. Inhibitory constants (Ki ) are strongly influenced by the diverse nature of the heterocycles and specific interactions with the local environment of the S3 pocket. Binding affinities vary by three orders of magnitude. All heteroaromatic ligands feature enhanced binding by comparison with hydrocarbon analogues. Predicted energetic contributions from the ori…
Metal complexes of anxiolitic drugs. X-Ray crystal structure and electronic properties of aquobromazepam(oxalato O1 O2) copper(II)
1987
The crystal structure of the title compound has been determined from single-crystal x-ray diffraction data. The copper(II) ion is surrounded by two nitrogen atoms of the bromazepam** molecule [N(imine) and N(pyridine)], and two oxygen atoms of the oxalate ion in a square planar arrangement. One molecule of water is linked to the copper(II) ion in the axial position. The complex has been also characterized by electronic, e.s.r. and i.r. spectra.
Nickel precursors based on diamagnetic and paramagnetic di(imine)pyridine ligands for magnetic materials: Synthesis, X-ray structures and magnetic st…
2018
International audience; Structural characterization and spectroscopic studies of the (2-acetyl-6-(1-TEMPO-imino)ethyl)pyridine (pat) and the 2,6-bis(1-TEMPO-imino)ethyl)pyridine (pbtMe) ligands are presented. Their electrochemical properties are also discussed. Two new nickel complexes, [NiII(dip)(CH3CN)(H2O)2](BF4)2 (1) (dip = 2,6-(di-iminepyridine)) and [NiII(pbtMe)(CH3CN)3](BF4)2 (2) have been characterized by X-ray diffraction. The reaction of 1 with the tetraethyl ammonium pentacyanopropenide salt (Et4N)(pcp) affords the new compound [NiII(pcp)(dip)(CH3CN)](pcp) (3) for which X-ray diffraction studies evidence an usual bridging μ2 coordination mode for the pentacyanopropenide anion, le…
Hapten Synthesis and Polyclonal Antibody-Based Immunoassay Development for the Analysis of Forchlorfenuron in Kiwifruit
2010
High-affinity polyclonal antibodies directed against the synthetic cytokinin forchlorfenuron (CPPU) were produced from three immunizing haptens with equivalent spacer arms located at different positions. A competitive immunoassay was developed with a limit of detection in buffer of 12.42 +/- 3.06 ng/L. In addition, the ability of the produced antibodies to recognize a set of synthetic CPPU analogues was studied. It was evidenced that the linker position had a strong impact on the specificity of the generated polyclonals, which were more sensitive to changes at moieties of the target analyte located furthest from the derivatization site of the immunogen. Finally, matrix effects of gold and g…
Hapten synthesis, monoclonal antibody generation, and development of competitive immunoassays for the analysis of picoxystrobin in beer.
2010
Abstract This paper describes the original synthesis of a functionalized derivative of the fungicide picoxystrobin and the generation of the first reported monoclonal antibodies against this strobilurin pesticide. The synthetic hapten was prepared by total synthesis from commercial chemicals and incorporating the spacer arm through a carbon–carbon single bond. Also, to obtain the immunogen, an uncommon hapten activation strategy based on N,N′-disuccinimidyl carbonate was employed, affording high activation yields and clean and reproducible coupling results. With these immunoreagents, two enzyme-linked immunosorbent assays (ELISAs) were developed: a competitive one-step assay using the antib…
Kinetics of the lipoperoxyl radical-scavenging activity of indicaxanthin in solution and unilamellar liposomes
2007
Abstract The reaction of the phytochemical indicaxanthin with lipoperoxyl radicals generated in methyl linoleate methanol solution by 2,20-azobis(2,4-dimethylvaleronitrile), and in aqueous soybean phosphatidylcholine unilamellar liposomes by 2,20-azobis(2- amidinopropane)hydrochloride, was studied. The molecule acts as a chain-terminating lipoperoxyl radical scavenger in solution, with a calculated inhibition constant of 3.63 £ 105M21 s21, and a stoichiometric factor approaching 2. Indicaxanthin incorporated in liposomes prevented lipid oxidation, inducing clear-cut lag periods and decrease of the propagation rate. Both effects were concentration-dependent, but not linearly related to the p…
3-[4-(1H-indol-3-yl)-1,3-thiazol-2-yl]-1H-pyrrolo[2,3-b]pyridines, nortopsentin Analogues with antiproliferative activity
2015
A new series of nortopsentin analogues, in which the imidazole ring of the natural product was replaced by thiazole and the indole unit bound to position 2 of the thiazole ring was substituted by a 7-azaindole moiety, was efficiently synthesized. Two of the new nortopsentin analogues showed good antiproliferative effect against the totality of the NCI full panel of human tumor cell lines (~60) having GI50 values ranging from low micromolar to nanomolar level. The mechanism of the antiproliferative effect of these derivatives, investigated on human hepatoma HepG2 cells, was pro-apoptotic, being associated with externalization of plasma membrane phosphatidylserine and mitochondrial dysfunctio…
The first authenticated example of triorganotin(IV) perchlorate complexes of some heterocyclic bases
1993
Abstract A convenient method is reported for the synthesis of some novel complexes of composition (R 3 SnL 2 ) ClO 4 where L represents pyridine, γ-picoline, 2,2′-bipyridine and 1,10-phenanthroline; and R n Bu or Ph. All of the new ionic complexes have been characterized by elemental analysis, molar conductance, infrared, multinuclear nuclear magnetic resonance ( 1 H, 13 C and 119 Sn) and 119 Sn Mossbauer spectroscopies. The complexes of composition (R 3 SnL 2 )ClO 4 exist both in solution and in the solid state with trans -trigonal bipyramidal structure where the R-groups occupy the equatorial positions while the ligands are in the axial position.