The Experts below are selected from a list of 783 Experts worldwide ranked by ideXlab platform
Antônio F. C. Alcântara - One of the best experts on this subject based on the ideXlab platform.
-
synthesis and characterization of chloro 2 1h Pyridinethione s tris pyridin 2 ylthiolato methyl c n n n nickel ii ni tptm spyh cl
Journal of Organometallic Chemistry, 2008Co-Authors: Flaviana T. Vieira, Geraldo M. De Lima, James L. Wardell, Solange M. S. V. Wardell, Klaus Krambrock, Antônio F. C. AlcântaraAbstract:Abstract The compound, [chloro{2(1H)-Pyridinethione- S }{tris(pyridin-2-ylthiolato)methyl- C,N,N ′, N ″]}nickel(II)], [Ni(TPTM)(SPyH)Cl], was isolated from the reaction between NiCl 2 · 6H 2 O and tris(pyridin-2-ylthiolato)methane in aqueous EtOH. X-ray crystallography at 120 K revealed an octahedral arrangement about Ni with a tetradentate tris(pyridin-2-ylthio)methyl- C,N,N,N ligand, a monodentate 2(1H)-Pyridinethione- S ligand and a chloride. The 2(1H)-Pyridinethione- S ligand was derived from tris(pyridin-2-ylthio)methane probably via an acid catalysed hydrolysis reaction. Intramolecular N–H–Cl and C–H–Cl interactions help to cement the molecular structure. Weak C–H–Cl and C–H–S hydrogen bonding interactions link molecules of [Ni(TPTM)(SPyH)Cl] into a 3D array. EPR and UV spectra, and Hartree–Fock theoretical calculations are reported.
-
Synthesis and characterization of [chloro(2(1H)-Pyridinethione-S)(tris(pyridin-2-ylthiolato)methyl-C,N,N',N ]}nickel(II)], [Ni(TPTM)(SPyH)Cl]
Journal of Organometallic Chemistry, 2008Co-Authors: Flaviana T. Vieira, Geraldo M. De Lima, James L. Wardell, Solange M. S. V. Wardell, Klaus Krambrock, Antônio F. C. AlcântaraAbstract:Abstract The compound, [chloro{2(1H)-Pyridinethione- S }{tris(pyridin-2-ylthiolato)methyl- C,N,N ′, N ″]}nickel(II)], [Ni(TPTM)(SPyH)Cl], was isolated from the reaction between NiCl 2 · 6H 2 O and tris(pyridin-2-ylthiolato)methane in aqueous EtOH. X-ray crystallography at 120 K revealed an octahedral arrangement about Ni with a tetradentate tris(pyridin-2-ylthio)methyl- C,N,N,N ligand, a monodentate 2(1H)-Pyridinethione- S ligand and a chloride. The 2(1H)-Pyridinethione- S ligand was derived from tris(pyridin-2-ylthio)methane probably via an acid catalysed hydrolysis reaction. Intramolecular N–H–Cl and C–H–Cl interactions help to cement the molecular structure. Weak C–H–Cl and C–H–S hydrogen bonding interactions link molecules of [Ni(TPTM)(SPyH)Cl] into a 3D array. EPR and UV spectra, and Hartree–Fock theoretical calculations are reported.
Hans Tjälve - One of the best experts on this subject based on the ideXlab platform.
-
Effect of zinc Pyridinethione on the tissue disposition of nickel and cadmium in mice.
Acta pharmacologica et toxicologica, 2009Co-Authors: Suhair Jasim, Hans TjälveAbstract:: Oral administration of zinc Pyridinethione together with 63Ni2+ or 109Cd2+ to mice resulted in increased levels of these metals in several tissues in comparison with animals given the metals alone. The disposition of the 63Ni2+ was affected more than the disposition of the 109Cd2+. Increased urinary excretion of the metals was also induced by the zinc Pyridinethione. Determinations of chloroform: water partition coefficients showed that lipophilic complexes are formed at equilibrations between Ni2+ or Cd2+ and zinc Pyridinethione. A facilitated penetration of the lipophilic metal complexes thorugh the cellular membranes in the gastrointestinal tract and in other tissues is probably important for the observed results. Our data suggest that effects on the disposition of metals may play a role for the toxicity of zinc Pyridinethione.
-
Effect of sodium Pyridinethione on the uptake and distribution of nickel in rats, ferrets and guinea-pigs
Archives of Toxicology, 1994Co-Authors: Kathleen Borg-neczak, Hans TjälveAbstract:Oral administration of sodium Pyridinethione together with Ni^2+ (using ^63Ni^2+ as a tracer) to rats, ferrets and guinea-pigs produced highly increased tissue levels of the metal in several tissues in comparison with animals given the Ni^2+ alone. Ni^2+ forms a lipophilic complex with Pyridinethione and it can be assumed that a facilitated passage of the Ni^2+ across the cellular membranes of various tissues is important for the observed effects. Pigmented tissues (e.g. the eye melanin), the pancreatic islets, the nervous system and striated muscles showed high levels of Ni^2+ in animals given sodium Pyridinethione. However, in some instances marked species differences were observed. Thus, microautoradiography indicated an uptake of Ni^2+ both in the \- and α-cells in the pancreatic islets in the rat, whereas in the guinea-pig only some cells (probably the α-cells) accumulated high levels of Ni^2+. In the ferret sodium Pyridinethione induced a high uptake of Ni^2+ in the heart muscle, which was not seen in the other species. The Ni^2+ is probably taken up in the various tissues complexed to Pyridinethione. Within the tissues the complex may dissociate and the Ni^2+ may bind to some endogeneous tissue components. The affinity of the Ni^2+ for the endogeneous ligands in relation to the affinity for the Pyridinethione may be of importance for the effects on the disposition of the Ni^2+. The species variations may be related to differences in the structural conformations of the endogeneous Ni^2+-binding ligands.
Chris Orvig - One of the best experts on this subject based on the ideXlab platform.
-
Theoretical studies of the tautomers of Pyridinethiones.
The Journal of Physical Chemistry A, 2008Co-Authors: Yu Adam Zhang, Vishakha Monga, Chris Orvig, Yan Alexander WangAbstract:Pyridinethiones are important ligand precursors of coordination complexes of therapeutic value. In aqueous solution, Pyridinethiones can dimerize and tautomerize to the corresponding thiols. However, the tautomerism of Pyridinethiones, which can impact on therapeutic performance, is yet not fully understood. To resolve this important issue, we have carried out ab initio and DFT calculations to compute the geometries, energies, dipole moments, and NMR, IR, and UV-vis spectroscopic properties of all possible tautomers of Pyridinethiones and compared our theoretical results with the existing experimental data. We found that the thione form of the tautomer is dominant for monomers of the Pyridinethiones studied here. This work can serve as a reference for exploring other similar organosulfur compounds.
-
group 13 and lanthanide complexes with mixed o s anionic ligands derived from maltol
Inorganic Chemistry, 2005Co-Authors: Vishakha Monga, Brian O Patrick, Chris OrvigAbstract:Four mixed O,S binding ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to gallium(III), indium(III), and lanthanide(III) ions to yield a series of metal complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), and two Pyridinethiones, 3-hydroxy-2-methyl-4(H)-Pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-Pyridinethione (Hdppt). Dimeric forms of the Pyridinethiones, Hmppt dimer and Hdppt dimer, were also isolated and characterized. Complete characterization of the monomeric organic compounds is reported including acidity constants and crystal structures of Htma, Hetma, and Hdppt dimer. Reacting the four monomeric ligand precursors with Ga3+ and In3+ ions yielded new tris(bidentate ligand) complexes. X-ray-quality crystals of the fac isomer of Ga(tma)3 were also obtained. New complexes with a range of lanthan...
-
vanadium complexes with mixed o s anionic ligands derived from maltol synthesis characterization and biological studies
Inorganic Chemistry, 2005Co-Authors: Vishakha Monga, Katherine H Thompson, Violet G Yuen, John H. Mcneill, Vijay Sharma, Brian O Patrick, Chris OrvigAbstract:Four mixed O,S binding bidentate ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to vanadium to yield new bis(ligand)oxovanadium(IV) and tris(ligand)vanadium(III) complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), as well as two Pyridinethiones, 3-hydroxy-2-methyl-4(H)-Pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-Pyridinethione (Hdppt). Vanadium complex formation was confirmed by elemental analysis, mass spectrometry, and IR and EPR (where possible) spectroscopies. The X-ray structure of oxobis(thiomaltolato)vanadium(IV),VO(tma)2, was also determined; both cis and trans isomers were isolated in the same asymmetric unit. In both isomers, the two thiomaltolato ligands are arranged around the base of the square pyramid with the VO linkage perpendicular; the vanadium atom is slightly displaced from the ...
Galal H Elgemeie - One of the best experts on this subject based on the ideXlab platform.
-
A new class of biheterocyclic thioglycosides from pyridine-2-(1H)-thiones.
Nucleosides nucleotides & nucleic acids, 2002Co-Authors: Galal H Elgemeie, Mona A. AhmedAbstract:ABSTRACT A reported method for preparation of a new class of biheterocyclic thioglycosides via reaction of Pyridinethiones with 2,3,4,6-tetra- O -acetyl-α-D-gluco- and galactopyranosyl bromides has been studied.
-
Novel Synthesis of a New Class of Polynuclear Pyridinethione Nucleosides
Nucleosides and Nucleotides, 1997Co-Authors: Galal H Elgemeie, Adel Attia, N. M. FathyAbstract:Abstract A novel synthesis of a new class of polynuclear Pyridinethione glycosides utilizing the reactions of phenanthridine analogues and α-bromoglucose or α-bromogalactose tetraacetate as starting components is described.
-
Glycosides of Heterocycles: A Direct Route to 1-(β-D-Glycopyranosyl)Pyridinethione Nucleosides
Liebigs Annalen der Chemie, 1994Co-Authors: Galal H Elgemeie, Adel M E Attia, Nahed M. FathyAbstract:A novel synthesis of 1-(β-D-glycopyranosyl)Pyridinethione nucleosides 6 utilizing pyridine-2(1H)-thiones 3 and α-halogeno sugars 4 as starting components is reported.
-
convenient synthesis of 2 1h Pyridinethione glycosides
Bulletin of the Chemical Society of Japan, 1994Co-Authors: Galal H Elgemeie, Adel M E Attia, A M Elzanate, A K MansourAbstract:A novel synthesis of 2(1H)-Pyridinethione glycosides utilizing 2(1H)-Pyridinethiones or their sodium salts and α-tetra-O-acetyl-glucosyl or D-galactosyl bromides as starting components is described.
-
Nucleotides and nucleosides: direct route to condensed Pyridinethione carbocyclic nucleosides related to 3-deazauridine
Journal of the Chemical Society Perkin Transactions 1, 1994Co-Authors: Galal H Elgemeie, Adel M E Attia, Dalia S. Farag, Sherif M. SherifAbstract:A novel synthesis of condensed Pyridinethione carbocyclic glycosides utilizing pyridine-2(1H)thiones and α-bromoglucose or α-bromogalactose tetraacetate as starting components is described.
V. P. Litvinov - One of the best experts on this subject based on the ideXlab platform.
-
Molecular and Crystal Structure of 5-Benzoyl-3-cyano-2-ethylthio-6-trifluoromethylpyridine
Chemistry of Heterocyclic Compounds, 2001Co-Authors: Ya. Yu. Yakunin, V. D. Dyachenko, Eduard B. Rusanov, V. P. LitvinovAbstract:An X-ray diffraction structural analysis on 5-benzoyl-3-cyano-2-ethylthio-6-trifluoromethylpyridine was carried out to establish the regioselectivity of the reactions of ethoxymethylene derivatives of 1-aryl- and 1-hetaryl-3-trifluoromethyl-1,3-diketones with cyanothioacetamide and the alkylation pathway of the Pyridinethiones obtained.
-
Michael reaction in synthesis of 6-amino-4-(4-butoxyphenyl)-3,5-dicyanopyridine-2(1H)-thione
Chemistry of Heterocyclic Compounds, 1998Co-Authors: V. D. Dyachenko, V. P. LitvinovAbstract:The reaction of 4-butoxybenzalcyanoacetic ester with cyanothioacetamide yielded 6-amino-4-(4-butoxyphenyl)-3,5-dicyanopyridine-2(1H)-thione, also synthesized by recyclization of 2,6-diamino-4-(4-butoxyphenyl)-3,5-dicyano-4H-thiopyran and condensation of 4-butyoxybenzaldehyde with a two-fold excess of cyanothioacetamide. Substituted 2-alkylthiopyridines and thieno[2,3- b ]pyridines were obtained with the indicated Pyridinethione.
-
Synthesis of 4-alkyl-6-amino-3,5-dicyano-2(1H)-Pyridinethiones
Chemistry of Heterocyclic Compounds, 1997Co-Authors: V. D. Dyachenko, Sergey G. Krivokolysko, Vladimir N. Nesterov, V. P. LitvinovAbstract:Condensation of aliphatic aldehydes with cyanothioacetamide has given 4-alkyl-6-amino-3,5-dicyano-2(1H)-Pyridinethiones, which have also been synthesized by recyclization of 4-alkyl-2,6-diamino-4H-thiopyrans. Substituted 2-alkylthiopyridines and thieno[2,3-b]pyridines have been prepared from the Pyridinethiones. 2,6-Diamino-4-isopropyl-3,5-dicyano-4H-thiopyran and 6-amino-4-isobutyl-2-methylthio-3,5-dicyanopyridine have been studied by x-ray crystallography.
-
N-acetylchloroacetamide in the synthesis of functionally-substituted pyrido[3′,2′∶4,5]-thieno[3,2-d]pyrimidin-4(3H)-ones
Chemistry of Heterocyclic Compounds, 1997Co-Authors: V. L. Ivanov, A. M. Shestopalov, V. A. Artemov, V. P. LitvinovAbstract:3-Cyano-2(1H)-Pyridinethiones react with N-acetylchloroacetamide in ethanol in the presence of KOH to give pyrido[3′,2′∶4,5]thieno[3,2-d]pyrimidin-4(3H)-ones.
-
β-Ketoaldehydes in the synthesis of 6-alkyl-3-cyano-2(1H)-Pyridinethiones
Russian Chemical Bulletin, 1995Co-Authors: N. G. Frolova, V. K. Zav'yalova, V. P. LitvinovAbstract:An efficient synthesis of 6-alkyl-3-cyano-2(1H)-Pyridinethiones by the reactions of the sodium salts of β-ketoaldehydes with cyanothioacetamide was developed. Pyridinethiones undergo selectiveS-alkylation with haloacetonitriles and haloacetophenones followed by cyclization to the corresponding thieno[2,3-b]pyridines.
