نتایج جستجو برای: pyridine
تعداد نتایج: 13677 فیلتر نتایج به سال:
The title compound, C(32)H(24)N(6)O(2), has an inversion centre located at the mid-point of the central C-C bond of the diether bridging unit. The terminal pyridine rings are canted relative to the central pyridine ring, with dihedral angles of 12.98 (6) and 26.80 (6)°. The maximum deviation from the eight-atom mean plane, defined by the two bridging O and C atoms and the central pyridine ring,...
The Reduction of Pyridine to 1,4-Dihydropyridine by Lithiumtetrahydroborate in the Presence of Water
In the presence of water lithium tetrahydroborate is capable of reducing pyridine to 1,4dihydropyridine. The product, lithiumtetrakis(pyridine) tetrakis(1,4-hydropyridyl)borate, was isolated and characterized by NMR and IR spectroscopy and single crystal X-ray diffraction. [Li(py)4][B(pyH)4]2(1,4-dioxane) crystallized in space group P42/n, Z = 2. Similarly, NaBH4 can also reduce pyridine in the...
The three-dimensional structure of Gynoside A, an ocotillone-type triterpenoid glycoside isolated from Gynostemma pentaphyllum, was determined in pyridine-d5 and DMSO-d6 solution through constrained molecular modeling using constraints derived from proton NMR spectra. The calculation yielded well-defined global minima. Except for some quantitative details the overall structure of Gynoside A in ...
2-Sulfanyl-6-(2-thienyl)pyridine-3-carbonitrile, 1-Amino-6-(5-bromo-benzofuran-2-yl)-2-oxo-1,2-dihydro-pyridine-3-carbonitrile, thieno[2,3-b]pyridins, pyrimidino[4',5':4,5] thieno[2,3-b]pyridine, quinazoline and carbamate derivatives were synthesized from sodium 3-(5-bromobenzofuran-2-yl)-3-oxoprop-1-en-1-olate with. The newly synthesized compounds were elucidated by elemental analysis, spectra...
The title compound, [U(C(5)H(7)O(2))(2)O(2)(C(6)H(6)N(2)O)], exhibits a penta-gonal-bipyramidal coordination geometry around the U(VI) atom, involving two bidentate acetyl-acetonate ions and the pyridine ring of the pyridine-4-carbaldehyde oxime ligand. Hydrogen bonds exist between the OH group of the pyridine-4-carbaldehyde oxime ligand and the two O atoms of the acetyl-acetonate ions.
New bis-(oxazolyl)pyridine ligands for Ln(III) ions were prepared using a expeditious methodology from threonine and dipicolinic acid chloride. The synthetic strategy includes a dehydration step to give a bis-dehydroaminobutyric acid derivative followed by bromination and cyclization with DBU. Photophysical studies of Eu(III) and Tb(III) complexes of these ligands showed that the 2,6-bis-(oxazo...
The title compound, C(19)H(19)N(3)O(4)S(2), was prepared by the reaction of 2,3-diamino-pyridine with tosyl chloride in a mixture of dichloro-methane-pyridine as solvent. In the crystal, mol-ecules associate via pairs of N-H⋯N hydrogen bonds, forming a centrosymmetric eight-membered {⋯HNCN}(2) synthon. The dihedral angles between the amino-pyridine ring and the tosyl benzene rings are 50.01 (6)...
In the title compound, C(17)H(17)NO(4), the dihedral angle between the benzene and pyridine rings is 75.51 (4)°. The benzene and pyridine rings are both approximately planar (r.m.s. deviations of 0.0040 and 0.0083 Å, respectively), indicating that the pyridine N atom is not protonated. The crystal structure is stabilized by weak inter-molecular C-H⋯O and C-H⋯N inter-actions.
The title compound, C(19)H(9)N(5)O(4), has crystallographically imposed twofold rotational symmetry. The asymmetric unit contains one half-mol-ecule. The crystal structure is stabilized by π-π stacking of inversion-related pyrrolo-[3,4-b]pyridine rings, with a centroid-centroid distance between stacked pyridines of 3.6960 (8) Å. The dihedral angle between the central pyridine ring and the pyrro...
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