- Poly organotin acetates against DNA with possible implementation on human breast cancer
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Two known tin-based polymers of formula {[R3 Sn(CH3 COO)]n} where R = n-Bu– (1) and R = Ph– (2),were evaluated for their in vitro biological properties. The compounds were characterized via their physical properties and FT
- Latsis, George K.,Banti, Christina N.,Kourkoumelis, Nikolaos,Papatriantafyllopoulou, Constantina,Panagiotou, Nikos,Tasiopoulos, Anastasios,Douvalis, Alexios,Kalampounias, Angelos G.,Bakas, Thomas,Hadjikakou, Sotiris K.
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- PROCESS FOR PRODUCTION OF DIALKYLTIN DIALKOXIDES
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An object of the present invention is to provide a process for producing a dialkyl tin compound from a composition of deactivated forms of a dialkyl tin catalyst, and to provide a process for producing the dialkyl tin catalyst from the dialkyl tin compound and using the dialkyl tin catalyst to produce a carbonic acid ester. According to the present invention, a process for producing a dialkyl tin compound is provided that subjects a composition of the deactivated forms of the dialkyl tin catalyst, formed when producing an ester compound, to an alkyl group redistribution reaction and/or dealkylation reaction.
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Page/Page column 34
(2009/07/25)
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- RADICAL TRAP IN FLUORIDATION OF IODONIUM SALT
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Decomposition of iodonium salts by a free radical process has been identified as a significant factor in the observed yield variability of fluoridation reactions using said iodonium salts. Accordingly, the inclusion of a free radical trap in the reaction mixture blocks the radical chain decomposition pathway for iodonium salts such that only the reaction leading to fluoridation can occur and the yield of aryl fluoride becomes high and reproducible. The reaction may also be carried out on solid phase. In both the solution and the solid phase the preferred method of the present invention is radiofluoridation.
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Page/Page column 24-25
(2008/06/13)
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- Novel carbon-carbon bond formation through Mizoroki-Heck type reaction of silanols and organotin compounds
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The reaction of dimethyl(phenyl)silanol with butyl acrylate in the presence of a stoichiometric amount of Pd(OAc)2 or by a combined use of 0.1 molar amount of Pd(OAc)2 and Cu(OAc)2/LiOAc (molar ratio 3/2) gave butyl cinnamate in 76% or 57% yield, respectively. The similar reaction with tributyl(phenyl)tin also proceeded in 77% yield. The organotin compound was shown to react faster than the sitanol, although the tin reagent sometimes induced undesirable homocoupling, while the reaction with silanol did not give such by-product.
- Hirabayashi, Kazunori,Ando, Jun-Ichi,Kawashima, Jun,Nishihara, Yasushi,Mori, Atsunori,Hiyama, Tamejiro
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p. 1409 - 1417
(2007/10/03)
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- Reactions of Organoytterbium Compounds RYbI (R = Me, Et, Ph) with Organotin Oxides and Acetates
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Reactions of RYbI (R = Me, Et, Ph) with organotin oxides and acetates) involve cleavage of the Sn-O bonds to form tetrasubstituted stannanes mostly as single or main reaction products (yields 65-96 percent). A similar results was obtained in reaction of PhYbI with diphenyltin sulfide (yield 93 percent). However, reactions of RYbI (R = Me, Et, Ph) with Bu2SnO, followed by hydrolysis of the reaction mixtures lead to hydroxystannanoxanes Bu2RSnOH in 66-75 percent yields.
- Rybakova, L. F.,Syutkina, O. P.,Novgorodova, M. N.,Petrov, E. S.
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- New latent organotin catalysts: Preparation and mechanism of the thermal decomposition of bis(2-(acyloxy)alkyl)diorganotins
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New organotin compounds, bis(2-(acyloxy)alkyl)diorganotins, can be thermally decomposed into diorganotin dicarboxylates. The substituent effects on the reaction parameters are studied, and a possible mechanism for the decomposition is proposed. These tetr
- Jousseaume, Bernard,Gouron, Véronique,Maillard, Bernard,Pereyre, Michel,Francès, Jean-Marc
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p. 1330 - 1331
(2008/10/08)
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- OXIDATIVE SUBSTITUTION REACTION OF OLEFINIC TIN COMPOUNDS WITH LEAD TETRAACETATE
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The oxidative substitution reaction of olefinic tin compounds with lead tetraacetate(LTA) was investigated.The oxidation is highly regioselective and gave a dipole inversed product (acetate) in good yield.
- Yamamoto, Makoto,Irie, Shin,Miyashita, Michio,Kohmoto, Shigeo,Yamada, Kazutoshi
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p. 221 - 222
(2007/10/02)
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- THE CHEMISTRY OF ORGANOLEAD(IV) TRICARBOXYLATES. SYNTHESIS AND ELECTROPHILIC HETEROARYLATION REACTIONS OF 2- AND 3-THIENYL-, AND 2- AND 3-FURYL-LEAD
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Tin(IV)-lead(IV) exchange and mercury(II)-lead(IV) exchange reactions have been used to obtain 2-thienyl-lead triacetate (3), 2-thienyl-lead tribenzoate (4), 3-thienyl-lead triacetate (16), 2-furyl-lead triacetate (21), and 3-furyl-lead triacetate (31).In reactions with the β-dicarbonyl compounds (7), (11), and (13), the above heteroaryl-lead compounds behaved as 2-thienyl, 3-thienyl, 2-furyl, and 3-furyl cation equivalents respectively, giving the α-heteroaryl β-dicarbonyl compounds (8), (12), (14), (17), (18), (19), (25), (27), (28), (38), (34), and (35) in synthetically useful yields.
- Pinhey, John T.,Roche, Eric G.
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p. 2415 - 2422
(2007/10/02)
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- α-Alkenylation of β-Dicarbonyl Compounds with 'Alk-1-enyl-lead Triacetates'
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Addition of lead tetra-acetate to a chloroform solution of a dialk-1-enylmercury or an alk-1-enyltributylstannane results in rapid formation of a relatively unstable species, believed to be an alk-1-enyl-lead triacetate, which can be used for the α-alkenylation of β-dicarbonyl compounds.
- Moloney, Mark G.,Pinhey, John T.
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p. 965 - 966
(2007/10/02)
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- BONDING ISOMERS OF TRIORGANOSTANNYL ENOLATES ANALYZED BY 119Sn NMR SPECTROSCOPY
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The bonding isomers of triorganostannyl enolates were analyzed by 119Sn NMR spectroscopy.In some cases the existence of an equilibrium between the O-stannyl enolate and C-stannyl derivative was confirmed by variable temperature 119Sn
- Kobayashi, Kazuko,Kawanisi, Mituyosi,Hitomi, Torazo,Kozima, Sinpei
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p. 497 - 500
(2007/10/02)
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- Electron-Transfer Activation in Electrophilic Mechanisms. Cleavage of Alkylmetals by Mercury(II) Complexes
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The disappearance of the transient charge-transfer (CT) absorption bands coincides with the electrophilic (SE2) cleavage of homologous series of alkyltin compounds by various mercury(II) halides, cyanide, and carboxylates.The second-order kinetics for HgCl2 cleavage afford rate constants which vary in a rather unaccountable way with the structure of the alkyltin compound and with the polarity of the solvent.Furthermore, the relative reactivities of these alkyltin compounds in the analogous electrophilic cleavage by I2 or Br2 show poor correlations with HgCl2 cleavages, in different solvents.However, the description of the activation process as an electron transfer in the precursor complex, e.g., -> +HgCl2->, stems from the CT transition energy and leads to a linear free energy relationship in which the activation free energy is equal to the driving force for the formation of the ion pair.The latter is readily dissected by eq 18 into separate changes in electronic, steric and solvation energies.With this mechanistic formulation, the reactivities of various alkyltin compounds follow a remarkably simple linear correlation with the ionization potentials and the solvent effects, in the comparison with I2 and Br2 cleavages.Moreover, the reactivities of the various mercury(II) derivatives relate directly to differences in their electron affinities.
- Fukuzumi, S.,Kochi, J. K.
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p. 7290 - 7297
(2007/10/02)
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- Enolstannanes as electrofugal groups in allylic alkylation
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Enolstannanes serve as nucleophiles towards allylic acetates under the influence of palladium(O) catalyst.
- Trost, Barry M.,Keinan, Ehud
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p. 2591 - 2594
(2007/10/02)
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- Urethane prepolymer
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A polyurethane prepolymer composition comprising (1) not less than 0.65 by weight of the idealized adduct from trimethylolpropane with 3 moles of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and (2) not more than 0.05 by weight of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate relative to the whole composition is very suitable for an isocyanate component of a two-package urethane coating and gives a coating film having excellent gloss, weathering resistance, adhesivity and impact resistance.
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