- Synthesis of novel pyrazole derivatives using organophosphorus, stibine, and arsine reagents and their antitumor activities
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The reactions of 5-azido-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (azidopyrazole) with several classes of organophosphorus reagents: phosphonium ylides, Wittig-Horner reagents, dialkylphosphonates, trialkylphosphites, tris(dialkylamino)phosphanes, triphenylstibane, triphenylarsane, and Lawesson's reagent are reported. Structural reasoning for the new products was based on compatible analytical and spectral data. The cytotoxic activity of most of the new products was evaluated against human breast carcinoma cell line (MCF7) and human hepatocellular carcinoma cell line(HepG2). Certain tested compounds showed promising results.
- El-Sayed, Naglaa F.,Ewies, Ewies F.,El-Hussieny, Marwa,Boulos, Leila S.,Shalaby, ElSayed M.
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p. 765 - 776
(2016/07/27)
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- Diverse structures and remarkable oxidizing ability of triarylbismuthane oxides. Comparative study on the structure and reactivity of a series of triarylpnictogen oxides
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A systematic series of triarylbismuthane oxides was prepared in order to disclose their structure and reactivity, which have been compared with those of lighter pnictogen counterparts. X-ray crystallographic analysis of tris(2-methoxyphenyl)bismuthane oxide and tris(2-methoxyphenyl)stibane oxide revealed that they exist as dimers with a flat bis(a-oxo) ring, implying that the polarized Bi+-O- and Sb+-O- bonds aggregate to attain electrostatic stabilization. In sharp contrast to their phosphorus, arsenic, and antimony counterparts, triarylbismuthane oxides are thermally unstable and possess a high oxidizing ability. In particular, the bismuthane oxides bearing ortho-substituted aryl ligands oxidized primary and secondary alcohols to aldehydes and ketones, respectively, with high efficiency under mild conditions.
- Matano, Yoshihiro,Nomura, Hazumi,Hisanaga, Teppei,Nakano, Haruyuki,Shiro, Motoo,Imahori, Hiroshi
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p. 5471 - 5480
(2008/10/09)
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- The structure of amorphous Ph3SbO: Information from EXAFS (extended X-ray absorption fine structure) spectroscopy
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EXAFS data for amorphous Ph3SbO are consistent with a structure in which trigonal-bipyramidal SbPh3O2 units share their axial oxygens to form a chain kinked at the oxygen atoms.
- Carmalt, Claire J.,Crossley, John G.,Norman, Nicholas C.,Orpen, A. Guy
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p. 1675 - 1676
(2007/10/03)
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- Reactions and properties of oxo and peroxo derivatives of (pentamethylcyclopentadienyl)-molybdenum and -tungsten
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The characterization and reactivity of complexes (η5-C5Me5)M(=O)(η2-O2)Cl (M=Mo, W) and (η5-C5Me5)M(=O)Cl3 are described.In addition, the preparation and reactivity of some molybdenum-oxoalkyl complexes are discussed in th
- Faller, J. W.,Ma, Yinong
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- The Chemistry of Pentavalent Organobismuth Reagents. Part 7. The Possible Role of Radical Mechanisms in the Phenylation Process for Bismuth(V), and Related Lead(IV), Iodine(III), and Antimony(V) Reagents
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The phenylation reactions of bismuth(V), lead(IV), and iodine(III) have been examined to test the presence or absence of phenyl radicals.In the case of several bismuth(V) reactions the presence of phenyl radicals has been detected, but it has been shown, by use of a large excess of radical trapping agent, that these radicals have nothing to do with the phenylation process.In the same way, the other phenylation reactions fail to respond to a large excess of a radical trap.
- Barton, Derek H. R.,Finet, Jean-Pierre,Giannotti, Charles,Halley, Frank
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p. 241 - 250
(2007/10/02)
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- Mechanism of the oxidation of triphenyl derivatives of P, As, and Sb by peroxodiphosphate
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Rate coefficients have been determined for the oxidation of Ph3M (M = P, As, Sb) by potassium peroxodiphosphate.The reaction is found to follow second-order kinetics, first order in each in the oxidant and Ph3M. +> has a pronounced accelerating effect on the reaction rate.An interesting dependence of the active species on the nature of the substrate has been observed.The reaction rate is influenced by changing the ionic strength of the medium.Acrylonitrile has no effect on the rate of oxidation.On the basis of the kinetic evidence, a general mechanism involving a bimolecular nucleophilic displacement of the substrate on the peroxo ion has been proposed.The relative rate order is found to be Ph3P > Ph3Sb > Ph3As and an explanation has been offered for the transposition of Ph3Sb and Ph3As.
- Srinivasan, C.,Pitchumani, K.
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p. 2285 - 2289
(2007/10/02)
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- Reactions of Carbonyl Sulphide with Palladium Compounds
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The reactions of carbonyl sulphide (COS) with PdCl2 (in dimethyl sulphoxide), Pd(PPh3)4, Pd(PPh3)2O2 and with PdCl2 in the presence or absence of PPh3 and AsPh3 have been investigated.The reaction products have been characterised and their reactions with PPh3, AsPh3 and SbPh3 or other small molecules have also been examined.The products have been characterised by elemental analyses, infrared spectra, conductivity measurements, magnetic moments and molecular weight measurements (wherever possible).In most of the cases COS forms molecular complexes.However, in some cases, it forms SPPh3 complexes.Reactions of the molecular COS complexes with other small molecules result in the replacement of COS.
- Datta, Someswar,Agarwala, U. C.
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p. 1190 - 1195
(2007/10/02)
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