- Synthesis and magnetic properties of a 4-(2′-pyrimidyl)-1,2,3,5- dithiadiazolyl dimanganese complex
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A spin-bearing bis-bidentate ligand, designed from a pyrimidyl-substituted R-CN2S2 neutral radical, is used to co-ordinate two Mn(ii) metal centres yielding a thermally stable complex with antiferromagnetic coupling between the ligand-centred spin and the metal-centred spins, and thus an overall ferrimagnetic coupling scheme with a ground state S = 9/2. The Royal Society of Chemistry 2006.
- Jennings, Michael,Preuss, Kathryn E.,Wu, Jian
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Read Online
- Oxidative carbonylation of methanol to dimethyl carbonate by chlorine-free homogeneous and immobilized 2,2′-bipyrimidine modified copper catalyst
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A chlorine-free catalyst, prepared in situ from Cu(II) acetate and 2,2′-bipyrimidine, can be used for the oxidative carbonylation of methanol to dimethyl carbonate. In situ high pressure IR and NMR spectroscopic studies suggest the formation of [Cu(2,2′-bipyrimidine)(CO)(OMe)] as one of the key intermediates. The catalytic performance of the 2,2′-bipyrimidine- modified Cu-catalyst is similar to the CuCl-based system. The chlorine free catalyst can be immobilized by using the copolymer of 5-vinyl-2,2′- bipyrimidine and styrene.
- Csihony, Szilard,Mika, Laszlo T.,Vlad, Gabor,Barta, Katalin,Mehnert, Christian P.,Horvath, Istvan T.
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Read Online
- Metal-free dehydrosulfurization of thioamides to nitriles under visible light
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A visible light-mediated, metal-free dehydrosulfurization reaction of thioamides to nitriles is described. This reaction features high yields, mild reaction conditions, and the use of a cheap organic dye as the photoredox catalyst and air as the oxidant.
- Xu, Tianxiao,Cao, Tianpeng,Feng, Qingyuan,Huang, Shenlin,Liao, Saihu
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supporting information
p. 5151 - 5153
(2020/05/26)
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- Copper-free Sandmeyer cyanation of arenediazonium o-benzenedisulfonimides
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Arene and heteroarenediazonium o-benzenedisulfonimides can be used as efficient reagents in Sandmeyer cyanation. This work reports such reactions carried out by us under very mild conditions using tetrabutyl ammonium cyanide as a safe cyanide source and, interestingly, without the need for a Cu catalyst. The reactions have given rise to aryl nitriles in good yields (25 examples, average yield 75%). A good amount of o-benzenedisulfonimide was recovered from each reaction and then reused to prepare other salts. Mechanistic insights have allowed us to highlight the fundamental role of the o-benzenedisulfonimide anion as an electron transfer agent.
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
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p. 1437 - 1441
(2016/02/03)
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- Electron-deficient heteroarenium salts: An organocatalytic tool for activation of hydrogen peroxide in oxidations
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A series of monosubstituted pyrimidinium and pyrazinium triflates and 3,5-disubstituted pyridinium triflates were prepared and tested as simple catalysts of oxidations with hydrogen peroxide, using sulfoxidation as a model reaction. Their catalytic efficiency strongly depends on the type of substituent and is remarkable for derivatives with an electron-withdrawing group, showing reactivity comparable to that of flavinium salts which are the prominent organocatalysts for oxygenations. Because of their high stability and good accessibility, 4-(trifluoromethyl)pyrimidinium and 3,5-dinitropyridinium triflates are the catalysts of choice and were shown to catalyze oxidation of aliphatic and aromatic sulfides to sulfoxides, giving quantitative conversions, high preparative yields and excellent chemoselectivity. The high efficiency of electron-poor heteroarenium salts is rationalized by their ability to readily form adducts with nucleophiles, as documented by low pKR+ values (pKR+ red > -0.5 V). Hydrogen peroxide adducts formed in situ during catalytic oxidation act as substrate oxidizing agents. The Gibbs free energies of oxygen transfer from these heterocyclic hydroperoxides to thioanisole, obtained by calculations at the B3LYP/6-311++g(d,p) level, showed that they are much stronger oxidizing agents than alkyl hydroperoxides and in some cases are almost comparable to derivatives of flavin hydroperoxide acting as oxidizing agents in monooxygenases.
- ?turala, Ji?í,Bohá?ová, Soňa,Chudoba, Josef,Metelková, Radka,Cibulka, Radek
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p. 2676 - 2699
(2015/03/18)
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- 3-Quinuclidinol as a nucleophilic catalyst for the cyanation of 2-chloropyrimidines
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3-Quinuclidinol serves as an effective nucleophilic catalyst for the preparation of 2-cyanopyrimidines by cyanation of 2-chloropyrimidines with potassium cyanide in good yields.
- Kim, Hong-Yong,Shieh, Wen-Chung,Prashad, Mahavir
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p. 5055 - 5057
(2015/01/09)
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- IMIDAZOTRIAZINONE COMPOUNDS
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The present invention provides imidazotriazinone compounds which are inhibitors of phosphodiesterase 9 and pharmaceutically acceptable salt thereof. The present invention further provides processes, pharmaceutical compositions, pharmaceutical preparations and pharmaceutical use of the compounds in the treatment of PDE9 associated diseases or disorders in mammals, including humans.
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Paragraph 0503
(2013/10/08)
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- IMIDAZOTRIAZINONE COMPOUNDS
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The present invention provides imidazotriazinone compounds which are inhibitors of phosphodiesterase 9. The present invention further provides processes, pharmaceutical compositions, pharmaceutical preparations and pharmaceutical use of the compounds in the treatment of PDE9 associated diseases or disorders in mammals, including CNS or neurodegeneration disorder.
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Page/Page column 79-80
(2012/04/10)
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- Mild and general methods for the palladium-catalyzed cyanation of aryl and heteroaryl chlorides
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New methods for the palladium-catalyzed cyanation of aryl and heteroaryl chlorides have been developed, featuring sterically demanding, electron-rich phosphines. Highly challenging electron-rich aryl chlorides, in addition to electron-neutral and electron-deficient substrates, as well as nitrogen- and sulfur-containing heteroaryl chlorides can all undergo efficient cyanation under relatively mild conditions using readily available materials. In terms of substrate scope and temperature, these methods compare very favorably with the state-of-the-art cyanations of aryl chlorides.
- Littke, Adam,Soumeillant, Maxime,Kaltenbach III, Robert F.,Cherney, Robert J.,Tarby, Christine M.,Kiau, Susanne
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p. 1711 - 1714
(2008/02/02)
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- 1-(Aromatic- or heteroaromatic-substituted)-3-(heteroaromatic substituted)-1,3-propanediones and uses thereof
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Certain 1-(aromatic- or heteroaromatic-substituted-3-(heteroaromatic substituted)-1,3-propanediones are described as inhibitors of HIV integrase and inhibitors of HIV replication. These compounds are useful in the prevention or treatment of infection by HIV and the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.
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- A new method for the generation of nitriles from aldoximes
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A mild and efficient method for the stereoselective dehydration of α-aldoximes to the corresponding nitriles is described which utilises methyl (carboxysulfamoyl)triethylammonium hydroxide inner salt (Burgess reagent) as the dehydrating agent.
- Jose, Binoy,Sulatha,Madhavan Pillai,Prathapan, Sreedharan
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p. 1509 - 1514
(2007/10/03)
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- Process for making pyrimidine derivatives
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The present invention provides a process for the manufacture of pyrimidines of formula I: STR1 wherein R1, R2, R3 each independently represent hydrogen, C1-7 -alkyl, or C1-7 -alkoxy, A signifies --CN, a carbanionic R4 -alkynyl residue, in which R4 is hydrogen or C1-7 -alkyl, or a carbanionic residue of the malonic acid derivative of formula III STR2 in which B and B' independently represent --CN, --COOR5, or --C(O)R5, wherein R5 is alkyl or aryl.
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- Azinyl and diazinyl hydrazones derived from aryl N-heteroaryl ketones: Synthesis and antiproliferative activity
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A series of N-heteroaryl hydrazones derived from aryl N-heteroaryl or bis-N-heteroaryl methanones was prepared in search for potential novel antitumor agents. The stereochemistry of these compounds was established by means of NMR spectroscopy. Antiproliferative activity was determined in a panel of human tumor cell lines (CCRF-CEM, Burkitt's lymphoma, HeLa, ZR-75- 1, HT-29, and MEXF 276L) in vitro. Generally, the new compounds were found to be more potent (IC50 = 0.011-0.436 μM) than the ribonucleotide reductase inhibitor hydroxyurea (IC50 = 140 μM). Most of the compounds exhibited the highest activity against Burkitt's lymphoma with an IC50 of 0.011-0.035 μM. [14C]Cytidine incorporation into DNA was quantitated for selected hydrazones (Z-A, E-1, Z-3, Z-4, E-5, Z-5, E-13, E-18, Z-19, Z-24, and E-26) as a measure of the inhibition of ribonucleotide reductase in Burkitt's lymphoma cells. The E-configurated compounds were found to inhibit [14C]cytidine incorporation to a greater extent (IC50 = 0.67-5.05 μM) than the Z-isomers (IC50 = 7.20 to > 10 μM). Principal component analysis of the IC50 values obtained for inhibition of cell proliferation revealed that the cell lines tested can be grouped into three main families showing different sensitivities toward the compounds in our series [(i) CCRF-CEM, Burkitt's lymphoma, and Hela; (ii) HT-29; and (iii) MEXF 276 L].
- Easmon,Heinisch,Purstinger,Langer,Osterreicher,Grunicke,Hofmann
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p. 4420 - 4425
(2007/10/03)
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- Development of a process to prepare 2-cyanopyrimidine on commercial scale
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2-Chloropyrimidine is converted to 2-cyanopyrimidine under very mild conditions in nearly quantitative yield using 1,4-diazabicyclo[2.2.2]octane as catalyst. The development of the process for commercial batch production of 2-cyanopyrimidine regarding processing of the materials in technical equipment, process safety, conservation, economic raw material use and work load is described.
- Goehring, Wolfgang,Schildknecht, Juerg,Federspiel, Muriel
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p. 538 - 543
(2007/10/03)
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- Synthesis of Cyano-Substituted Heterocycles by Means of Tetraethylammonium Cyanide
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Chloropyrimidines 2, 3 and Chlorquinazolines 9, 10, after conversion into trimethylammonio derivatives 4, 5, 11, 12, react with tetraethylammonium cyanide 1a under very mild conditions to give pyrimidine carbonitriles 6, 7 and quinazoline carbonitriles 13, 14.Direct synthesis of quinoxaline carbonitriles 19 is possible by reaction of chloroquinoxalines 15, 18 with 1a.
- Hermann, Klaus,Simchen, Gerhard
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p. 333 - 341
(2007/10/02)
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