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Bioorganic Chemistry Dec 2014Phosphodiesterases (PDEs) have been studied in a variety of tumours; data have suggested that the levels of PDE activities are elevated and, therefore, the ratios of...
Phosphodiesterases (PDEs) have been studied in a variety of tumours; data have suggested that the levels of PDE activities are elevated and, therefore, the ratios of cGMP to cAMP are affected. In addition, PDE inhibitors are potential targets for tumour cell growth inhibition and induction of apoptosis. Nonselective PDE inhibitors, such as theophylline or aminophylline, are known regulators of growth in a variety of carcinoma cell lines, suggesting a potential role for PDE inhibitors as anticancer drugs. In the current study, we reported the synthesis of novel derivatives of 6-aryl-4-imidazolyl-2-imino-1,2-dihydropyridine-3-carbonitriles (Ia,b,c) and their 2-oxo isosteres (IIa,b,c,d). All the compounds were evaluated for their PDE3A inhibitory effects, as well as their cytotoxic effects on MCF-7 and HeLa cell lines. Moreover, structure-activity relationships were studied. 4-(1-benzyl-2-ethylthio-5-imidazolyl)-6-(4-bromophenyl)-2-imino-1,2-dihydropyridine-3-carbonitrile (Ib) exhibited the strongest PDE3A inhibitory effects with an IC50 of 3.76±1.03nM. Compound Ib also showed the strongest cytotoxic effects on both the HeLa and MCF-7 cells with an IC50 of 34.3±2.6μM and 50.18±1.11μM, respectively. There was a direct correlation between PDE3 inhibition and anticancer activity for the synthesised compounds. The data reported here support our view that PDEs represent promising cellular targets for antitumor treatment.
Topics: Antineoplastic Agents; HeLa Cells; Humans; MCF-7 Cells; Neoplasms; Phosphodiesterase 3 Inhibitors; Phosphoric Diester Hydrolases; Pyridines
PubMed: 25277835
DOI: 10.1016/j.bioorg.2014.09.003 -
Carbohydrate Polymers Feb 2014Chitosan was chemically modified through a sequence of four reactions with immobilized 2-aminomethylpyridine at the final stage, after prior protection of amino group...
Chitosan was chemically modified through a sequence of four reactions with immobilized 2-aminomethylpyridine at the final stage, after prior protection of amino group with benzaldehyde. The characterized biopolymers containing free amino and hydroxyl active centers on the biopolymeric structure and pyridinic nitrogen on pendant chains showed combined hydrophobic properties that can potentially favor interactions. Reactive Yellow GR and Blue RN dyes gave the maximum sorption capacities of 2.13 and 1.61 mmol g(-1), which were performed as functions of contact time, concentration and dye structure. However, biopolymer/dye interactions are governed by effective hydrogen bond and van der Waals forces for such structural adjustments. The data obtained from the concentration isotherm were applied to non-linear regressions of the Langmuir, the Freundlich and the Sips models, with the best fit to the latter model. The kinetic data was fitted to non-linear regression of pseudo-second-order, indicating that the sorption phenomena are most likely to be controlled by chemisorption process.
Topics: Biopolymers; Chitosan; Coloring Agents; Kinetics; Magnetic Resonance Spectroscopy; Pyridines; Spectrophotometry, Infrared; Textiles; Thermogravimetry; X-Ray Diffraction
PubMed: 24507253
DOI: 10.1016/j.carbpol.2013.10.075 -
Biotechnology and Bioengineering Sep 2015Employing an internal circulation baffled biofilm reactor (ICBBR), we evaluated the mechanisms by which photolysis accelerated the biodegradation and mineralization of...
Employing an internal circulation baffled biofilm reactor (ICBBR), we evaluated the mechanisms by which photolysis accelerated the biodegradation and mineralization of pyridine (C5 H5 N), a nitrogen-containing heterocyclic compound. We tested the hypothesis that pyridine oxidation is accelerated because a key photolysis intermediate, succinate, is as electron donor that promotes the initial mono-oxygenation of pyridine. Experimentally, longer photolysis time generated more electron-donor products (succinate), which stimulated faster pyridine biodegradation. This pattern was confirmed by directly adding succinate, and the stimulation effect occurred similarly with addition of the same equivalents of acetate and formate. Succinate, whether generated by UV photolysis or added directly, also accelerated mono-oxygenation of the first biodegradation intermediate, 2-hydroxyl pyridine (2HP). 2HP and pyridine were mutually inhibitory in that their mono-oxygenations competed for internal electron donor; thus, the addition of any readily biodegradable donor accelerated both mono-oxygenation steps, as well as mineralization.
Topics: Biodegradation, Environmental; Bioreactors; Electrons; Photolysis; Pyridines; Succinic Acid; Ultraviolet Rays
PubMed: 25854706
DOI: 10.1002/bit.25605 -
Spectrochimica Acta. Part A, Molecular... Feb 2008Infrared absorption spectra of copper phthalocyanine in KBr pellet and pyridine solution in 400-1625 and 2900-3200 cm(-1)regions are reported. In the IR spectra of solid...
Infrared absorption spectra of copper phthalocyanine in KBr pellet and pyridine solution in 400-1625 and 2900-3200 cm(-1)regions are reported. In the IR spectra of solid sample, presence of weak bands, which are forbidden according to the selection rules of D4h point group, is explained on the basis of distortion in the copper phthalocyanine molecule caused by the crystal packing effects. Observation of a new band at 1511 cm(-1) and change in intensity of some other bands in pyridine are interpreted on the basis of coordination of the solvent molecule with the central copper ion.
Topics: Indoles; Molecular Structure; Organometallic Compounds; Pyridines; Spectrophotometry, Infrared
PubMed: 17572136
DOI: 10.1016/j.saa.2007.05.012 -
Fundamental and Applied Toxicology :... Nov 1994Pyridine is a volatile solvent used as an intermediate in the production of insecticides, herbicides, pharmaceuticals, and dyes. Pyridine is also found in tobacco smoke....
Pyridine is a volatile solvent used as an intermediate in the production of insecticides, herbicides, pharmaceuticals, and dyes. Pyridine is also found in tobacco smoke. Because inhalation is a primary route of exposure to pyridine, we examined the effect of inhaled pyridine on morphology at the portal of entry, the nose. Nasal tissues from F344/N rats exposed using a nose-only mode 6 hr/day for 4 days to either filtered air (controls) or one of two concentrations of pyridine vapor were examined histologically. The rats had been killed 18 hr after the last exposure. The two pyridine concentrations were the current threshold limit value (TLV, 5 ppm) and a high concentration (444 ppm). Olfactory epithelial lesions in rats exposed to both concentrations of pyridine included vacuolar degeneration of sustentacular cells; focal, marked attenuation of the epithelium; loss of vacuolar degeneration of sustentacular cells; focal, marked attenuation of the epithelium; loss of neurons; and the presence of intraepithelial luminal structures. The lesions were only slightly more severe in the rats exposed to 444 ppm compared to those rats exposed to 5 ppm pyridine. The results show that inhalation of pyridine at the current TLV concentration of 5 or 444 ppm causes lesions in the olfactory epithelium of rats.
Topics: Administration, Inhalation; Animals; Male; Maximum Allowable Concentration; Olfactory Mucosa; Pyridines; Rats; Rats, Inbred F344
PubMed: 7867902
DOI: 10.1006/faat.1994.1135 -
Molecules (Basel, Switzerland) Feb 2024Disubstituted isothiazolo[4,3-]pyridines are known inhibitors of cyclin G-associated kinase. Since 3-substituted-7-aryl-isothiazolo[4,3-]pyridines remain elusive, a...
Disubstituted isothiazolo[4,3-]pyridines are known inhibitors of cyclin G-associated kinase. Since 3-substituted-7-aryl-isothiazolo[4,3-]pyridines remain elusive, a strategy was established to prepare this chemotype, starting from 2,4-dichloro-3-nitropyridine. Selective C-4 arylation using ligand-free Suzuki-Miyaura coupling and palladium-catalyzed aminocarbonylation functioned as key steps in the synthesis. The 3--morpholinyl-7-(3,4-dimethoxyphenyl)-isothiazolo[4,3-]pyridine was completely devoid of GAK affinity, in contrast to its 3,5- and 3,6-disubstituted congeners. Molecular modeling was applied to rationalize its inactivity as a GAK ligand.
Topics: Pyridines; Models, Molecular; Palladium; Ligands; Cyclin G; Catalysis
PubMed: 38474466
DOI: 10.3390/molecules29050954 -
Pharmaceutical Bulletin Mar 1954
Topics: Nicotine; Pyridines
PubMed: 13177116
DOI: 10.1248/cpb1953.2.37 -
Dalton Transactions (Cambridge, England... Nov 2010A number of manganese-based catalysts employing ligands whose structures incorporate pyridyl groups have been reported previously to achieve both high turnover numbers...
A number of manganese-based catalysts employing ligands whose structures incorporate pyridyl groups have been reported previously to achieve both high turnover numbers and selectivity in the oxidation of alkenes and alcohols, using H(2)O(2) as terminal oxidant. Here we report our recent finding that these ligands decompose in situ to pyridine-2-carboxylic acid and its derivatives, in the presence of a manganese source, H(2)O(2) and a base. Importantly, the decomposition occurs prior to the onset of catalysed oxidation of organic substrates. It is found that the pyridine-2-carboxylic acid formed, together with a manganese source, provides for the observed catalytic activity. The degradation of this series of pyridyl ligands to pyridine-2-carboxylic acid under reaction conditions is demonstrated by (1)H NMR spectroscopy. In all cases the activity and selectivity of the manganese/pyridyl containing ligand systems are identical to that observed with the corresponding number of equivalents of pyridine-2-carboxylic acid; except that, when pyridine-2-carboxylic acid is used directly, a lag phase is not observed and the efficiency in terms of the number of equivalents of H(2)O(2) required decreases from 6-8 equiv. with the pyridin-2-yl based ligands to 1-1.5 equiv. with pyridine-2-carboxylic acid.
Topics: Alkenes; Amines; Catalysis; Hydrogen-Ion Concentration; Iron; Ligands; Manganese; Oxidation-Reduction; Picolinic Acids; Pyridines
PubMed: 20886164
DOI: 10.1039/c0dt00452a -
Inorganic Chemistry Dec 2010Determination of transient structures in light-induced processes is a challenging goal for time-resolved techniques. Such techniques are becoming successful in detecting...
Determination of transient structures in light-induced processes is a challenging goal for time-resolved techniques. Such techniques are becoming successful in detecting ultrafast structural changes in molecules and do not require the presence of probe-like groups. Here, we demonstrate that TR-WAXS (Time-Resolved Wide Angle X-ray Scattering) can be successfully employed to study the photochemistry of cis-[Ru(bpy)(2)(py)(2)]Cl(2), a mononuclear ruthenium complex of interest in the field of photoactivatable anticancer agents. TR-WAXS is able to detect the release of a pyridine ligand and the coordination of a solvent molecule on a faster timescale than 800 ns of laser excitation. The direct measurement of the photodissociation of pyridine is a major advance in the field of time-resolved techniques allowing detection, for the first time, of the release of a multiatomic ligand formed by low Z atoms. These data demonstrate that TR-WAXS is a powerful technique for studying rapid ligand substitution processes involving photoactive metal complexes of biological interest.
Topics: 2,2'-Dipyridyl; Antineoplastic Agents; Models, Molecular; Molecular Structure; Organometallic Compounds; Photochemistry; Photolysis; Pyridines; Scattering, Radiation; X-Rays
PubMed: 21038911
DOI: 10.1021/ic102021k -
Luminescence : the Journal of... Dec 2015Poly(p-pyridinium phenylene ethynylene)s (PPyPE) functionalized with alternating donor-acceptor repeat units were synthesized by a Pd-catalyzed Sonogashira coupling...
Poly(p-pyridinium phenylene ethynylene)s (PPyPE) functionalized with alternating donor-acceptor repeat units were synthesized by a Pd-catalyzed Sonogashira coupling reaction between diethynyl monomer and di-iodopyridine for use as a pH-responsive fluorescence chemical sensor. The synthesized PPyPE, containing pyridine units, was characterized by FT-IR, (1)H and (13)C NMR, UV-visible and fluorescence spectroscopies. We investigated the relationship between changes of optical properties and protonation/deprotonation of PPyPE containing pyridine units in solution. Addition of HCl decreased and red-shifted the fluorescence intensity of the conjugated polymers that contained pyridine rings; fluorescence intensity of the polymers increased upon addition of NaOH solution. The synthesized PPyPE was found to be an effective and reusable chemical sensor for pH sensing.
Topics: Fluorescence; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Molecular Structure; Polymers; Pyridines; Pyridinium Compounds; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared
PubMed: 25828634
DOI: 10.1002/bio.2898