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ChemSusChem Jul 2016The recently proposed highly efficient route of pyridine-catalyzed CO2 reduction to methanol was explored on platinum electrodes at high CO2 pressure. At 55 bar...
The recently proposed highly efficient route of pyridine-catalyzed CO2 reduction to methanol was explored on platinum electrodes at high CO2 pressure. At 55 bar (5.5 MPa) of CO2 , the bulk electrolysis in both potentiostatic and galvanostatic regimes resulted in methanol production with Faradaic yields of up to 10 % for the first 5-10 C cm(-2) of charge passed. For longer electrolysis, the methanol concentration failed to increase proportionally and was limited to sub-ppm levels irrespective of biasing conditions and pyridine concentration. This limitation cannot be removed by electrode reactivation and/or pre-electrolysis and appears to be an inherent feature of the reduction process. In agreement with bulk electrolysis findings, the CV analysis supported by simulation indicated that hydrogen evolution is still the dominant electrode reaction in pyridine-containing electrolyte solution, even with an excess CO2 concentration in the solution. No prominent contribution from either a direct or coupled CO2 reduction was found. The results obtained suggest that the reduction of CO2 to methanol is a transient process that is largely decoupled from the electrode charge transfer.
Topics: Carbon Dioxide; Catalysis; Electrochemistry; Electrodes; Electrolysis; Oxidation-Reduction; Pressure; Pyridines
PubMed: 27253886
DOI: 10.1002/cssc.201600267 -
Helvetica Chimica Acta 1945
Topics: Pyridines
PubMed: 20998078
DOI: No ID Found -
European Journal of Medicinal Chemistry Jun 2014We describe our rationale for designing specific catalytic inhibitors of topoisomerase II (topo II) over topoisomerase I (topo I). Based on 3D-QSAR studies of previously...
We describe our rationale for designing specific catalytic inhibitors of topoisomerase II (topo II) over topoisomerase I (topo I). Based on 3D-QSAR studies of previously published dihydroxylated 2,4-diphenyl-6-aryl pyridine derivatives, 9 novel dihydroxylated 2,4-diphenyl-6-thiophen-2-yl pyridine compounds were designed, synthesized, and their biological activities were evaluated. These compounds have 2-thienyl ring substituted on the R(3) group on the pyridine ring and they all showed excellent specificity toward topo II compared to topo I. In vitro experiments were performed for compound 13 to determine the mechanism of action for this series of compounds. Compound 13 inhibited topoisomerase II specifically by non-intercalative binding to DNA and did not stabilize enzyme-cleavable DNA complex. Compound 13 efficiently inhibited cell viability, cell migration, and induced G1 arrest. Also from 3D-QSAR studies, the results were compared with other previously published dihydroxylated 2,4-diphenyl-6-aryl pyridine derivatives to explain the structure-activity relationships.
Topics: Apoptosis; Biocatalysis; Cell Line, Tumor; DNA; DNA Topoisomerases, Type II; Drug Design; Humans; Hydroxides; Models, Molecular; Protein Conformation; Pyridines; Quantitative Structure-Activity Relationship; Topoisomerase II Inhibitors
PubMed: 24796883
DOI: 10.1016/j.ejmech.2014.04.066 -
Biological & Pharmaceutical Bulletin Feb 2003In the present study, a series of 2-substituted-pyridines were synthesized and characterized by IR, (1)H-NMR and Elemental Analysis. The compounds were assayed against...
In the present study, a series of 2-substituted-pyridines were synthesized and characterized by IR, (1)H-NMR and Elemental Analysis. The compounds were assayed against seizures induced by maximal electro shock (MES) and pentylenetetrazole (scMet). Neurologic deficit was evaluated by the rotarod test. The decrease in the elevated motor activity by introceptive chemical stimuli (amphetamine antagonistic activity) was studied at the dose level of 25 and 50 mg/kg, antihistaminic and cardiac activity were also studied. All the compounds exhibited significant anticonvulsant activity. Compounds 2-(2'-piperazino-ethanoxy)pyridine, 2-(3'-morpholino-2'-hydroxypropyloxy)pyridine, 2-(3'-piperidino-2'-hydroxypropyloxy)pyridine and 2-(3'-piperazino-2'-hydroxypropyloxy)pyridine were most active of the series against MES-induced seizures. Compounds 2-(2'-piperazino-ethanoxy)pyridine, 2-(2'-phenylamino-ethanoxy)pyridine, 2-(3'-imidazolo-2'-hydroxypropyloxy)pyridine, 2-(3'-methylamino-2'-hydroxypropyloxy)pyridine and 2-(3'-piperidino-2'-hydroxypropyloxy)pyridine exhibited significant decrease in the elevated motor activity at the dose of 50 mg/kg. Remarkable sympathetic blocking activity was observed with 2-(3'-piperazino-2'-hydroxypropyloxy)pyridine, 2-(3'-piperidino-2'-hydroxypropyloxy)pyridine and 2-(3'-imidazolo-2'-hydroxypropyloxy)pyridine only. Compounds 2-(2'-morpholino-ethanoxy)pyridine, 2-(2'-piperidino-ethanoxy)pyridine, 2-(2'-piperazino-ethanoxy)pyridine, 2-(2'-imidazolo-ethanoxy)pyridine, 2-(2'-diphenylamino-ethanoxy)pyridine, 2-(2'-diethanolamino-ethanoxy)pyridine, 2-(2'-phenylamino-ethanoxy)pyridine and 2-(2'-(4"-hydroxy)phenylamino-ethanoxy)pyridine exhibited significant blocking of histamine induced contraction on guinea pig ileum.
Topics: Animals; Anticonvulsants; Anura; Drug Evaluation, Preclinical; Female; Guinea Pigs; Ileum; In Vitro Techniques; Male; Mice; Pyridines; Seizures; Structure-Activity Relationship
PubMed: 12576677
DOI: 10.1248/bpb.26.182 -
Journal of the American Chemical Society Mar 2013We describe here a [3+3]-type condensation reaction of O-acetyl ketoximes and α,β-unsaturated aldehydes that is synergistically catalyzed by a copper(I) salt and a...
We describe here a [3+3]-type condensation reaction of O-acetyl ketoximes and α,β-unsaturated aldehydes that is synergistically catalyzed by a copper(I) salt and a secondary ammonium salt (or amine). This redox-neutral reaction allows modular synthesis of a variety of substituted pyridines under mild conditions with tolerance of a broad range of functional groups. The reaction is driven by a merger of iminium catalysis and redox activity of the copper catalyst, which would initially reduce the oxime N-O bond to generate a nucleophilic copper(II) enamide and later oxidize a dihydropyridine intermediate to the pyridine product.
Topics: Aldehydes; Amines; Catalysis; Copper; Molecular Structure; Oximes; Pyridines; Quaternary Ammonium Compounds
PubMed: 23437938
DOI: 10.1021/ja312346s -
Applied Biochemistry and Biotechnology Feb 2015A series of 6-tosyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide analogues are synthesized by conventional techniques and characterized by elemental analysis,...
A series of 6-tosyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide analogues are synthesized by conventional techniques and characterized by elemental analysis, IR, MS, (1)H, and (13)C NMR. These are tested for their antibacterial activity against Bacillus subtilis (abbreviated as BS), Staphylococcus aureus (abbreviated as SA), and Escherichia coli (abbreviated as EC). The synthesized compounds are able to inhibit the growth of the SA and EC. None of the compounds are effective against BS. All valence molecular orbital (abbreviated as MO) calculations with PM6 have been carried out for the molecules for which bioactivity data are available. Ciprofloxacin is taken as the standard antibiotics to compare activity with the molecules synthesized. It has been attempted to correlate the activity of the molecules with their electronic structure.
Topics: Anti-Bacterial Agents; Bacillus subtilis; Ciprofloxacin; Electrons; Escherichia coli; Microbial Sensitivity Tests; Pyridines; Staphylococcus aureus
PubMed: 25422060
DOI: 10.1007/s12010-014-1399-8 -
Macromolecular Rapid Communications Mar 2018Crosslinked high-performance polymers have many industrial applications, but are difficult to recycle or rework. A novel class of recyclable crosslinking...
Crosslinked high-performance polymers have many industrial applications, but are difficult to recycle or rework. A novel class of recyclable crosslinking Cu(II)-metallo-supramolecular coordination polymers are successfully prepared, which possess outstanding thermal stability and mechanical property. More importantly, the Cu coordination interactions can be further removed via external pyrophosphate to recover the linear polymers, which endow the crosslinking polymers with recyclability.
Topics: Copper; Cross-Linking Reagents; Diphosphates; Magnetic Resonance Spectroscopy; Polymers; Pyridines; Spectroscopy, Fourier Transform Infrared
PubMed: 29314342
DOI: 10.1002/marc.201700573 -
Bioorganic & Medicinal Chemistry Letters Jul 2016It is assumed that amyloid-β aggregation is a crucial event in the pathogenesis of Alzheimer's disease. Novel 2,6-disubstituted pyridine derivatives were designed to...
It is assumed that amyloid-β aggregation is a crucial event in the pathogenesis of Alzheimer's disease. Novel 2,6-disubstituted pyridine derivatives were designed to interact with the β-sheet conformation of Aβ via donor-acceptor-donor hydrogen bond formation. A series of pyridine derivatives were synthesized and tested regarding their potential to inhibit the aggregation of Aβ. The 2,6-diaminopyridine moiety was identified as a key component to inhibit Aβ aggregation. Overall, compounds having three 2,6-disubstituted pyridine units separated by at least one C2- or C3-linker displayed the most potent inhibition of Aβ aggregation.
Topics: Amyloid beta-Peptides; Dose-Response Relationship, Drug; Humans; Molecular Structure; Protein Aggregates; Pyridines; Structure-Activity Relationship
PubMed: 27256911
DOI: 10.1016/j.bmcl.2016.05.040 -
Bioorganic & Medicinal Chemistry Letters Jul 2019Despite their clinical importance, drug resistance remains problematic for microtubule targeting drugs. D4-9-31, a novel microtubule destabilizing agent, has...
Despite their clinical importance, drug resistance remains problematic for microtubule targeting drugs. D4-9-31, a novel microtubule destabilizing agent, has pharmacology that suggests it can overcome common resistance mechanisms and has been shown to remain efficacious in cell and animal models with acquired taxane resistance. To better understand resistance mechanisms and the breadth of cross-resistance with D4-9-31, this study examines the A2780 ovarian cancer cell line as it develops acquired resistance with continuous exposure to D4-9-31. Analyzing cellular responses to D4-9-31 reveals that D4-9-31 resistance is associated with increased mitochondrial respiration, but no cross-resistance to other microtubule targeting agents is observed. Sequencing of transcripts of parental cells and resistant counterparts reveals mutations and altered expression of microtubule-associated genes, but not in genes commonly associated with resistance to microtubule targeting drugs. Additionally, our findings suggest distinct mechanisms drive short- and long-term drug resistance.
Topics: Amides; Humans; Microtubules; Polymerization; Pyridines; Pyrimidines
PubMed: 31047749
DOI: 10.1016/j.bmcl.2019.04.035 -
Chemphyschem : a European Journal of... Jan 2013A study of crystal structures from the Cambridge Structural Database (CSD) and DFT calculations reveals that parallel pyridine-pyridine and benzene-pyridine interactions...
A study of crystal structures from the Cambridge Structural Database (CSD) and DFT calculations reveals that parallel pyridine-pyridine and benzene-pyridine interactions at large horizontal displacements (offsets) can be important, similar to parallel benzene-benzene interactions. In the crystal structures from the CSD preferred parallel pyridine-pyridine interactions were observed at a large horizontal displacement (4.0-6.0 Å) and not at an offset of 1.5 Å with the lowest calculated energy. The calculated interaction energies for pyridine-pyridine and benzene-pyridine dimers at a large offset (4.5 Å) are about 2.2 and 2.1 kcal mol(-1), respectively. Substantial attraction at large offset values is a consequence of the balance between repulsion and dispersion. That is, dispersion at large offsets is reduced, however, repulsion is also reduced at large offsets, resulting in attractive interactions.
Topics: Benzene; Computer Simulation; Databases, Chemical; Dimerization; Hydrogen Bonding; Models, Molecular; Pyridines; Thermodynamics
PubMed: 23090910
DOI: 10.1002/cphc.201200607