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31.
A novel tandem one-pot method for the synthesis of polysubstituted pyridine derivatives has been developed via Knoevenagel-type reaction and subsequent 6π electrocyclization of the Blaise reaction intermediates and 3-formylchromones. Short reaction time, moderate to good yields and excellent functional group tolerance have been accomplished in this protocol. 相似文献
32.
Amino acids are firstly employed in transition-metal free heterocyclization reaction of 1,3-diynes in the presence of K3PO4 and DMSO at 120 °C. This method produces 2,3,6-trisubstituted pyridines with up to 86% yield. The –CO2H group on the amino acids is crucial for this heterocyclization reaction. The mechanism of such a heterocyclization reaction is discussed, as well. 相似文献
33.
The readily available homochiral ligand (1) was used to prepare four mononuclear nickel and cobalt complexes with a 2:1 ligand:metal ratio. X-ray crystal structures of these revealed that in all cases the N,N,O-tridentate ligand adopts facial coordination to the metal with the pyridine rings trans-disposed and the carboxylate and amine groups cis. The individual crystal structures of these compounds differ significantly in the way the complexes pack, which is mediated by hydrogen bonding involving the cations, anions and water molecules as well as, in one case, π-stacking. 相似文献
34.
Four copper(II) complexes (1–4) and a cobalt(II) complex (5) derived from 4-bromo-2-(hydroxymethyl)pyridine (L1) or 5-bromo-2-hydroxymethyl)pyridine (L2) with Cu(NO3)2·3H2O, CuCl2·2H2O and CoCl2·6H2O have been synthesized and their respective crystal structures studied. They show specific influences owing to the different kind of metal cations and counter anions, the hydration as well as the different position of the bromine substitution on both the coordination of the complex unit and the network structure of the crystal lattice. The Cu(II) complexes of L1 are five-coordinate [Cu(L1)2NO3]NO3·H2O (1) and [Cu(L1)2Cl]Cl·H2O (2) species with distorted quadratic pyramidal and trigonal bipyramidal coordination geometries of the N2O3 and N2O2Cl donor atoms around the Cu(II), respectively. The Cu(II) complexes of L2 are six-coordinate [Cu(L2)2(NO3)2] (3) and [Cu(L2)2Cl(H2O)]Cl·H2O (4) species with distorted octahedral coordination geometries of the N4O2 and N2O3Cl donor atoms. A distorted octahedral coordination geometry of the N2O2Cl2 donor atoms is also found in the complex unit [Co(L2)2Cl2] of the Co(II) complex 5 but showing the oxygen atoms of the chelating ligand as well as the chloride ions in a cis-position. Depending on the complex, water molecules and chloride anions are shown to act as stabilizing components of the crystal structure. The comparative structural investigation includes also known structures of the bromine-free ligand analogue 2-(hydroxymethyl)pyridine, illustrating the basic implication of the bromine substitution, mostly perceptible in the different modes of crystal packing. 相似文献
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36.
Cevher Altug Alan K. BurnettEsra Caner Ya?ar DürüstMark C. Elliott Roger P.J. GlanvilleCarol Guy Andrew D. Westwell 《Tetrahedron》2011,67(49):9522-9528
A series of thiazolo[3,2-a]pyridines have been prepared using a multicomponent reaction between aromatic aldehydes, 2-nitromethylenethiazolidine and nitriles containing an active methylene group (malononitrile, ethyl 2-cyanoacetate and 2-phenylsulfonylacetonitrile) in the presence of Et3N under mild conditions with high yields. One of the compounds shows promising anticancer activity across a range of cancer cell lines. 相似文献
37.
38.
Iwao Okamoto Masayuki TerashimaHyuma Masu Mayumi NabetaKaori Ono Nobuyoshi MoritaKosuke Katagiri Isao AzumayaOsamu Tamura 《Tetrahedron》2011,67(44):8536-8543
A series of cis-preferential aromatic N-methyl amides was designed and synthesized, and acid-induced conformational alteration of these compounds was investigated by means of NMR measurements in solution and X-ray crystal structure analysis. Compounds with a terminal N-methyl-N-(2-pyridyl) amide unit showed acid-induced conformational change from cis to trans, while those with a terminal N-methyl-2-pyridinecarboxamide unit showed a change of the carbonyl orientation from anti to syn with retention of cis conformation. 相似文献
39.
Jennifer M. StorvickEvgenia Ankoudinova Brianne R. KingHeather Van Epps Gregory W. O’Neil 《Tetrahedron letters》2011,52(44):5858-5861
The total synthesis of haminol A has been completed featuring a masked-alkene metathesis reaction followed by bis-acyloxysulfone elimination to install the 1,3,8-triene subunit. During the course of our synthesis, the metathesis reactivity of 3-vinylpyridine was evaluated and our data suggest the rapid formation of a ruthenium pyridylalkylidene that no longer participates in productive metathesis. A chemotaxis assay using Caenorhabditis elegans demonstrated that haminol A produced an avoidance response from this organism. 相似文献
40.
Two novel organotin supramolecular coordination polymers (SCP), namely, 3∞[Me3SnCu(CN)2·(EN)2], 1 and 3∞[Ph3SnCu(CN)2·(3-mpy)2], 2 are obtained by the reactions of K3[Cu(CN)4], ethyl nicotinate (EN) or 3-methylpyridine (3-mpy) and Me3SnCl or Ph3SnCl in H2O/acetonitrile solution at room temperature. 2D-layers are constructed via H-bonds between the parallel 1D-puckered chains which contain nanometer-sized [-CN(R3Sn)NC-] spacers connecting the tetrahedral (T-4) copper sites. The network structures of 1 and 2 consist of infinite layers connected by interlayer H-bonds forming 3D-framworks. 2 is the first compound in this family containing the Ph3Sn cation. The electronic absorption spectra of 1 and 2 reveal a broad band at 320 nm due to CT transition while the emission spectra exhibit high energy bands at 400-460 nm due to metal-centered (MC) transitions and low energy bands at 485-530 nm corresponding to MLCT. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the in vitro antitumor effects of the SCP 1 and 2 on human breast cancer cell line, ZR-75-1. Cell cycle analysis revealed that the SCP 1 and 2 induced apoptosis in ZR-75-1 breast cancer cell line through activating caspase-3. Moreover, in vivo model, the compound SCP 2 suppressed tumor growth developed mammary carcinoma by 52.3%. Taken together, our novel compounds selectivity exhibit specific in vivo and in vitro antitumor effects. 相似文献