- Neutral complexes of first row transition metals bearing unbound thiocyanates and their assembly on metallic surfaces
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A series of transition metal coordination complexes designed to assemble on gold surfaces was synthesized, their electronic structure and transitions analyzed, and their magnetic properties studied. By taking advantage of recently developed thiocyanate assembly protocols, these molecules were then assembled onto a gold surface, without the need for an inert atmosphere, to give a loosely packed monolayer. The assembled molecules exhibit properties similar to that of the bulk molecules, indicating little change in molecular structure outside of chemisorption.
- Ciszek, Jacob W.,Keane, Zachary K.,Cheng, Long,Stewart, Michael P.,Yu, Lam H.,Natelson, Douglas,Tour, James M.
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- Synthesis and antiproliferative activity of 2,5-bis(3′-Indolyl) pyrroles, analogues of the marine alkaloid nortopsentin
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2,5-bis(3′-Indolyl)pyrroles, analogues of the marine alkaloid nortopsentin, were conveniently prepared through a three step procedure in good overall yields. Derivatives 1a and 1b exhibited concentration-dependent antitumor activity towards a panel of 42 human tumor cell lines with mean IC50 values of 1.54 μM and 0.67 μM, respectively. Investigating human tumor xenografts in an ex-vivo clonogenic assay revealed selective antitumor activity, whereas sensitive tumor models were scattered among various tumor histotypes.
- Carbone, Anna,Parrino, Barbara,Barraja, Paola,Spano, Virginia,Cirrincione, Girolamo,Diana, Patrizia,Maier, Armin,Kelter, Gerhard,Fiebig, Heinz-Herbert
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- A fulvene route to group 4 metallocene complexes bearing 4,7-bis(dimethylamino)-substituted indenyl ligands
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N,N,N′,N′-Tetramethylsuccinamide (15) was selectively converted into the functionalized aminofulvene 16. Subsequent treatment with reagent 17, [ZrCl2(NMe2)2(L)2] (L = THF or 0.5 DME), resulted in the formation of the cyclization product 4,7- bis(dimethylamino)indene (21). Deprotonation with n-butyllithium, followed by the reaction of the resulting substituted indenyllithium reagent 22 with ZrCl4, gave the metallocene [4,7-bis(dimethylamino)indenyl] 2ZrCl2 (23). The reaction of 22 with ZrCl3Cp furnished the complex [4,7-bis(dimethylamino)indenyl]CpZrCl2 (24). Fulvene 16, as well as the metallocene dichlorides 23 and 24, were characterized by X-ray diffraction. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Sierra, Jesus Cano,Kehr, Sierra Gerald,Froehlich, Roland,Erker, Gerhard
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- Dethreading of Tetraalkylsuccinamide-Based [2]Rotaxanes for Preparing Benzylic Amide Macrocycles
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The dethreading of a series of succinamide-based [2]rotaxanes bearing benzylic amide macrocycles is reported herein. These transformations proceeded quantitatively either under flash vacuum pyrolysis, conventional heating, or microwave irradiation. Studying the size complementarity of the stoppers at the ends of the thread and the cavity of the macrocycle allowed us to set up the best substituents for implementing the extrusion of the thread from the interlocked precursors. A variety of 1H NMR kinetic experiments were carried out in order to evaluate the rate constants of the dethreading process, the half-life times of the rotaxanes, and the influence of temperature and solvents on these processes. The use of dibutylamino groups as stoppers yielded the rotaxane precursor in a reasonable yield and allowed the quantitative deslipping of the rotaxane. The overall process, including the rotaxane formation and its further dethreading, has been exploited for preparing benzylic amide macrocycles enhancing, in most cases, the results of the classical (2 + 2) condensation and other reported stepwise syntheses. The kinetics of the dethreading process is fairly sensitive to the electronic effects of the substituents on the isophthalamide unit or to the electronic nature of the pyridine rings through a conformational equilibrium expanding or contracting the cavity of the interlocked precursor.
- Martinez-Cuezva, Alberto,Rodrigues, Leticia V.,Navarro, Cristian,Carro-Guillen, Fernando,Buriol, Lilian,Frizzo, Clarissa P.,Martins, Marcos A. P.,Alajarin, Mateo,Berna, Jose
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p. 10049 - 10059
(2015/11/03)
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- Copper-catalyzed homodimerization of nitronates and enolates under an oxygen atmosphere
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A method for copper-catalyzed oxidative dimerization of nitronates and enolates using oxygen as the terminal oxidant has been developed. Cyclization through oxidative intramolecular coupling is also feasible for both nitronates and enolates. The mild reaction conditions lead to good functional group tolerance.
- Do, Hien-Quang,Tran-Vu, Hung,Daugulis, Olafs
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p. 7816 - 7818
(2013/01/16)
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- PRODUCT CONTAINING DIAMIDES, METHOD FOR MAKING SAME AND USES THEREOF
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The product comprises at least two diamide compounds selected from the diamide compounds of following formulae (Ia), (Ib), and (Ic): [in-line-formulae]R2R3NOC-Aa-CONR4R5??(Ia)[/in-line-formulae] [in-line-formulae]R2R3NOC-Ab-CONR4R5??(Ib)[/in-line-formulae] [in-line-formulae]R2R3NOC-Ac-CONR4R5??(Ic)[/in-line-formulae] wherein: R2, R3, R4, and R5, either identical or different, are groups selected from saturated or unsaturated, linear or branched, optionally cyclic, optionally aromatic, optionally substituted, hydrocarbon groups comprising an average number of carbon atoms ranging from 1 to 36, R2 and R3 on the one hand and R4 and R5 on the other hand may optionally form together a ring, optionally substituted and/or optionally comprising a heteroatom, andAa, Ab, and Ac are linear divalent alkyl groups, each comprising a different number of carbon atoms.
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Page/Page column 7
(2012/02/06)
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- Synthesis and antitumor activity of 2,5-bis(3′-indolyl)-furans and 3,5-bis(3′-indolyl)-isoxazoles, nortopsentin analogues
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A series of novel 2,5-bis(3′-indolyl)furans and 3,5-bis(3′-indolyl)isoxazoles were synthesized as antitumor agents. The antiproliferative activity was evaluated in vitro toward diverse human tumor cell lines. Initially 5 isoxazoles and 3 furan derivatives were tested against a panel of 10 human tumor cell lines and the most active derivatives 3c and 4a were selected to be evaluated in an extended panel of 29 cell lines. By exhibiting mean IC50 values of 17.4 μg/mL (3a) and 20.5 μg/mL (4c), in particular 4c showed a high level of tumor selectivity toward the 29 cell lines.
- Diana, Patrizia,Carbone, Anna,Barraja, Paola,Kelter, Gerhard,Fiebig, Heinz-Herbert,Cirrincione, Girolamo
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experimental part
p. 4524 - 4529
(2010/08/22)
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- Synthesis of amides
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Alkyl amides have been synthesized from cyclic anhydrides, carboxyl acids and their esters by contacting them with an amine carbamic acid salt.
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