- Synthesis of high specific activity tritium-labelled dotriacontane
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The tobacco smoke particulate phase marker dotriacontane was labelled with tritium at positions 15, 16, 17 and 18 by the catalytic reduction of dotriaconta-15, 17-diyne. This was obtained by oxidatively coupling hexadec-1-yne, in turn prepared by reaction of monosodium acetylide with myristyl bromide.
- Houseman,Binns,Phillips
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Read Online
- Reductive Homocoupling of Organohalides Using Nickel(II) Chloride and Samarium Metal
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A homocoupling method for organohalides and organosulfonates promoted by samarium metal and HMPA, and catalyzed by NiCl2 has been developed. Various organohalides (benzyl, aryl, heterocyclic, alkenyl and alkyl halides), α-haloacetophenones, and phenyl organosulfonates were tolerated, and the reaction afforded coupling products with high efficiency. Excellent chemoselectivity was exhibited between halides and other groups, such as ?COOH, ?NO2, halogen, heterocyclic ring, ester, and ketone groups. The stereoselectivity suggested that the reaction mechanism might involve an organosamarium species.
- Liu, Yongjun,Xiao, Shuhuan,Qi, Yan,Du, Feng
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supporting information
p. 673 - 678
(2017/03/22)
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- Efficient heterogeneous dual catalyst systems for alkane metathesis
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A fully heterogeneous and highly efficient dual catalyst system for alkane metathesis (AM) has been developed. The system is comprised of an alumina-supported iridium pincer catalyst for alkane dehydrogenation/olefin hydrogenation and a second heterogeneous olefin metathesis catalyst. The iridium catalysts bear basic functional groups on the aromatic backbone of the pincer ligand and are strongly adsorbed on Lewis acid sites on alumina. The heterogeneous systems exhibit higher lifetimes and productivities relative to the corresponding homogeneous systems as catalyst/catalyst interactions and bimolecular decomposition reactions are inhibited. Additionally, using a two-pot device, the supported Ir catalysts and metathesis catalysts can be physically separated and run at different temperatures. This system with isolated catalysts shows very high turnover numbers and is selective for the formation of high molecular weight alkanes.
- Huang, Zheng,Rolfe, Eleanor,Carson, Emily C.,Brookhart, Maurice,Goldman, Alan S,El-Khalafy, Sahar H.,Roy MacArthur, Amy H.
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experimental part
p. 125 - 135
(2010/06/20)
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- Glassy carbon modified by a silver-palladium alloy: cheap and convenient cathodes for the selective reductive homocoupling of alkyl iodides
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Micrometer-thick layers of silver-palladium alloy were elaborated in order to modify the surface of glassy carbon electrodes. Such a surface modification can be readily achieved via a preliminary silver galvanostatic deposit onto carbon followed by a 'palladization' step, thanks to a simple immersion in acidic PdII-based solutions producing a displacement reaction. The as-prepared metallic interfaces exhibit outstanding catalytic capabilities especially in the cleavage of carbon-halogen bonds while being chemically/electrochemically quite stable and relatively inexpensive. More specifically, the use of such glassy carbon/Ag-Pd electrodes in dimethylformamide (DMF) containing tetraalkylammonium salts (TAA+X-) makes the one-electron reductions of primary alkyl iodides possible; this reduction leads to the formation of homodimers in high yields. Formation of a free radical as transient resulted from the homocoupling reaction.
- Poizot, Philippe,Jouikov, Viatcheslav,Simonet, Jacques
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body text
p. 822 - 824
(2009/05/07)
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- Indium promoted reductive homocoupling of alkyl and aryl halides
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Reductive homocoupling of alkyl and aryl halides in presence of indium metal in DMF produces bialkyls and biaryls in good yields. 1,4-Diketones are obtained from α-iodoketones.
- Ranu, Brindaban C.,Dutta, Pinak,Sarkar, Arunkanti
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p. 9557 - 9558
(2007/10/03)
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- The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Catalyst.II. Homocoupling of 1-Iodoalkanes
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The hydrogenolysis and dimerization of iodoalkanes were catalyzed by Pd in the presence of an appropriate reducing agent.Hydrazine was found to be effective for the coupling of 1-iodoeicosane to give tetracontane, C40H82, in a 74 percent yield.The yield of the coupling product decreased with the decrease of the number of the carbon atoms in the 1-iodoalkanes.Both alkylhydrazines and alkenes were shown not to take part in the reaction as a reaction intermediate.
- Nakajima, Riichiro,Morita, Kazuhiro,Hara, Tadashi
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p. 3599 - 3600
(2007/10/02)
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