- Kinetics and Mechanism of the Oxidation of Phosphinic, Phenylphosphinic, and Phosphorous Acids by Pyridinium Fluorotrioxochromate(VI)
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Oxidation of the lower phosphorus oxyacids by results in the formation of corresponding oxyacids in the higher valence states.The reaction is first order with respect to the oxidant concentration.A Michaelis-Menten type kinetics was observed with respect to the substrate, indicating the formation of a complex in a pre-equilibrium.The formation constants and the rates of disproportionation of the complexes have been evaluated at different temperatures.The reaction exhibits a substantial primary kinetic isotope effect.The rates in 19 different organicsolvents have been analysed using Kamlet-Taft and Swain equations.It has been found that the cation-solvating power of the solvents plays an important role.It is proposed that the 'inactive ' tautomer of the phosphorus oxyacids is the reactive reductant, and that transfer of a hydride ion from the P-H bond to the oxidant in the rate-determining step occurs.
- Moondra, Anu,Mathur, Abha,Banerji, Kalyan K.
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- Kinetics and mechanisms of electron-transfer reactions of bismuth(V) in aqueous acidic perchlorate-fluoride media. Part 1. Oxidation of hypophosphorous acid
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Solutions of bismuth(V) from NaBiO3 have been obtained in 1.0 mol dm-3 HClO4 and 1.5 mol dm-3 HF with a view to studying the redox system involving BiV and H3PO2.The reaction is first order in the concentration of each of BiV, H3PO2, and H+.It is catalysed by BiIII through complex formation with the reactive species HBiF6.The rate law (i) holds where Kp is the protonation constant of - and K the complex formation constant between BiV and BiIII.The values of Kpk and K were found to be 0.125+/-0.015 dm6 mol-2 s-1 and 45+/-6 dm3 mol-1 respectively at 35 deg C and I = 2.0 mol dm-3, k' and k are the second-order rate constants for the reaction between HBiF6 and H3PO2, and the complex and H3PO2 respectively.Bismuth(V) does not absorb in the u.v. region but BiIII does, the wavelength depending on the source of BiIII and the medium.
- Inani, Krishnadass M.,Sharma, Prem Dutt,Gupta, Yugul Kishore
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- The relative hydrolytic reactivities of pyrophosphites and pyrophosphates
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The pH-rate profiles for the hydrolysis of pyrophosphate (PP(v)) and pyrophosphite (PP(iii), pyro-di-H-phosphonate) are a complex function of pH, reflecting the different ionic species and their relative reactivities. PP(iii) is more reactive than PP(v) at all pHs and only PP(iii) shows a hydroxide-ion reaction at high pH, so it is 1010-fold more reactive than PP(v) in 0.1 M NaOH. The pKa2 of PP(iii) ~0.44, so the dominant species at pH's > 1 is the di-anion PP(iii)2-. Although there is no observable (NMR or ITC) binding of Mg2+ to the PP(iii) di-anion there is a modest increase in the rate of hydrolysis of PP(iii) by Mg2+. PP(iii) is neither a substrate nor an inhibitor of pyrophosphatase, the enzyme that efficiently catalyses the hydrolysis of PP(v).
- Mistry, Dharmit,Powles, Nicholas
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- Kinetics and Mechanism of Oxidation of Phosphinic, Phenylphosphinic, and Phosphonic Acids by Pyridinium Chlorochromate
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Oxidation of the lower oxyacids of phosphorus by pyridinium chlorochromate (PCC) results in the formation of the corresponding higher oxyacids of phosphorus.The reaction is of first order with respect to PCC and the oxyacid.The reaction is catalyzed by hydrogen ions, kobs = a + b.The reaction exhibited a substantial primary kinetic isotope effect.The rates in 19 different organic solvents have been analyzed using Kamlet-Taft's and Swains's equations.It has been found that the cation-solvating power of the solvents plays a predominant role.It is proposed that the "inactive" tautomer of the phosphorus oxyacids is the reactiv e species.Transfer of a hydride ion from the P-H bond to PCC, in the rate-determining step, has been proposed.
- Seth, Monila,Mathur, Abha,Banerji, Kalyan K.
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- 31PNMR study on the reactions of amino acids and sugar derivatives with pyrophosphorous acid as a possible prebiotic phosphonylating agent
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Phosphorus is an essential element in living organisms. Evaluating prebiotic processes that lead to phosphorylated biomolecules is an important step toward understanding the origin of life. Schreibersite ([Fe,Ni]3P) is a meteoritic phosphorus mineral which releases various phosphorus species reactive toward biomolecules. We studied the reactions between biomolecules and pyrophosphorus acid (H4P2O5), which is a phosphorous acid derivative released from schreibersite. The reactions between pyrophosphorous acid and molecules having hydroxy groups were carried out under mild alkaline conditions. Notably, some biologically important molecules such as L-serine, L-tyrosine, L-threonine, D-ribose, and D-glyceraldehyde reacted with pyrophosphorous acid to give corresponding phosphonates. These results suggested that if schreibersite and the biomolecules co-existed in the prebiotic earth, they formed the phosphonates which were able to play roles as surrogates or precursors of phosphorylated biomolecules.
- Seio, Kohji,Shiozawa, Takashi,Sugiyama, Daiki,Ohno, Kentaro,Tomori, Takahito,Masaki, Yoshiaki
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- Oxidation of white phosphorus by peroxides in water
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A mixture of hypophosphorous, phosphorous, and phosphoric acids is formed during the anaerobic oxidation of white phosphorus by peroxides [ROOН; R = Н, 3-ClC6H4CO, (СН3)3С] in water. The rate of reactions grows considerably upon adding nonpolar organic solvents. The activity series of peroxides and solvents are determined experimentally. NMR spectroscopy shows that the main product of the reaction is phosphorous acid, regardless of the nature of the peroxide and solvent. A radical mechanism of oxidation of white phosphorus by peroxides in water is proposed. It is initiated by the homolysis of peroxide with the formation of НO? radicals that are responsible for the homolytic opening of phosphoric tetrahedrons. Further oxidation and stages of the hydrolysis of intermediate phosphorus-containing compounds yield products of the reaction.
- Abdreimova,Akbaeva,Polimbetova
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- Electrochemical generation of P4 2- dianion from white phosphorus
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Electrochemical reduction of elemental (white) phosphorus in an undivided cell equipped with a sacrificial metal anode (Al, Co, Nb, Sn) results in the formation of the reduced form of white phosphorus, P4 2- dianion, which was detected in solution by 31P NMR spectroscopy.
- Yakhvarov,Gorbachuk,Khayarov, Kh. R.,Morozov,Rizvanov, I. Kh.,Sinyashin
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- New experimental data and mechanistic studies on the bromate-dual substrate-dual catalyst batch oscillator
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The bromate-hypophosphite-acetone-Mn(II)-Ru(bpy)32+ batch oscillator was recently suggested for studying two-dimensional pattern formation. The system meets all major requirements that are needed for generation of good quality traveling waves in a thin solution layer. The serious drawback of using the system for studying, temporal and spatial dynamical phenomena is its unknown chemical mechanism. In order to develop a mechanism that explains the observed long-lasting batch oscillations the bromate-hypophosphite-acetone-Mn(II)-Ru(bpy)32+ oscillator was revisited. We studied the dynamics both in the total system and in some composite reactions, and kinetic measurements were carried out in three subsystems. From the new experimental results we concluded that the two oscillatory sequences observed in the full system are originated from two oscillatory subsystems, the Mn(II)-catalyzed bromate-hypophosphite-acetone and the Ru(bpy)32+-catalyzed bromate-bromoacetone reactions. Here we propose a mechanism which is capable of simulating the dynamical features that appeared in the complex system.
- Szalai, Istvan,Kurin-Csoergei, Krisztina,Horvath, Viktor,Orban, Miklos
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- The first water-soluble tetraphosphorus ruthenium complex. Synthesis, characterization and kinetic study of its hydrolysis
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Reaction of the water-soluble complex [CpRu(TPPMS)2Cl] (1) [TPPMS = sodium salt of m-monosulfonated triphenylphosphine, Ph 2P(m-C6H4SO3Na)] with 1 equiv of white phosphorus in the presence of TlPFsub
- Caporali, Maria,Gonsalvi, Luca,Kagirov, Rustam,Mirabello, Vincenzo,Peruzzini, Maurizio,Sinyashin, Oleg,Stoppioni, Piero,Yakhvarov, Dmitry
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- Kinetics and mechanisms of reactions of alkyl hydroperoxides with methylrhenium oxides
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Aqueous methyldioxorhenium (MDO), prepared from methyltrioxorhenium (MTO) and hypophosphorous acid, abstracts an oxygen atom from tertiary alkyl hydroperoxides. This regenerates MTO and forms the tertiary alcohol with rate constants 3.71 × 104 L mol-1 s-1 (t-BuOOH) and 3.47 × 104 L mol-1 s-1 (t-AmOOH) at 25.0 °C in aqueous 1.0 M HOTf. MDO reacts with hydrogen peroxide first to form MTO, k = 3.36 × 104 L mol-1 s-1, which subsequently reacts with more hydrogen peroxide to form peroxorhenium complexes. In a separate study, the concomitant slow decomposition of alkyl hydroperoxides and MTO (to ReO4-) was investigated. The rate law is v = k[MTO][RCMe2OOH]/[H+], with k = 7.4 × 10-5 s-1 (R = Me) and k = 8.4 × 10-5 s-1 (R = Et) at 25.0 °C in aqueous solution at μ 1.0 M. 1H NMR spectroscopy and GC revealed organic products suggestive of radical reactions. The products from t-BuOOH are acetone, methanol, tert-butyl methyl ether, methane, ethane, and rerf-butyl methyl peroxide. With CH2DReO3, it could be shown that both t-BuOOH and MTO were sources of the methane. The rate of decomposition of MTO shows an inverse-first-order dependence on [H+] throughout the range pH 1-6.42.
- Brittingham, Kimberly A.,Espenson, James H.
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- Synthesis of monophosphines directly from white phosphorus
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Monophosphorus compounds are of enormous industrial importance due to the crucial roles they play in applications such as pharmaceuticals, photoinitiators and ligands for catalysis, among many others. White phosphorus (P4) is the key starting material for the preparation of all such chemicals. However, current production depends on indirect and inefficient, multi-step procedures. Here, we report a simple, effective ‘one-pot’ synthesis of a wide range of organic and inorganic monophosphorus species directly from P4. Reduction of P4 using tri-n-butyltin hydride and subsequent treatment with various electrophiles affords compounds that are of key importance for the chemical industry, and it requires only mild conditions and inexpensive, easily handled reagents. Crucially, we also demonstrate facile and efficient recycling and ultimately catalytic use of the tributyltin reagent, thereby avoiding the formation of substantial Sn-containing waste. Accessible, industrially relevant products include the fumigant PH3, the reducing agent hypophosphorous acid and the flame-retardant precursor tetrakis(hydroxymethyl)phosphonium chloride. [Figure not available: see fulltext.]
- Scott, Daniel J.,Cammarata, Jose,Schimpf, Maximilian,Wolf, Robert
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p. 458 - 464
(2021/04/09)
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- Hydrolysis stability of bidentate phosphites utilized as modifying ligands in the Rh-catalyzed n-regioselective hydroformylation of olefins
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The stability of ligands and catalysts is an almost neglected issue in homogeneous catalysis, but it is crucial for successful application of this methodology in technical scale. We have studied the effect of water on phosphites, which are the most applied cocatalysts in the n-regioselective homogeneous Rh-catalyzed hydroformylation of olefins. The stability of the bidentate nonsymmetrical diphosphite L1, as well as its two monophosphite constituents L2 and L3, toward hydrolysis was investigated by means of in situ NMR spectroscopy under similar conditions as applied in industry. Hydrolysis pathways, intermediates, and kinetics were clarified. DFT calculations were used to support the experimentally found data. The acylphosphite unit L2, which reacts with water in an unselective manner, was proven to be much less stable than the phenolphosphite L3. The stability of the bidentate ligand L1 can be therefore mainly attributed to its phenolphosphite moiety. With an excess of water, the hydrolysis of L1 and L2 as well as their Rh-complexes is first-order with respect to the phosphite. Surprisingly, coordination to Rh significantly stabilizes the monodentate ligand L2, while in strong contrast, the bidentate ligand L1 decomposes faster in the Rh complex. NMR spectroscopy provided evidence for the existence of species from decomposition of phosphites, which can likewise coordinate as ligands to the metal. Electron-withdrawing groups in the periphery of the acylphosphite moiety decrease the stability of L1, whereas 3,5-disubstituted salicylic acid derivatives with bulky groups showed superior stability. These modifications of L1 also give rise to different catalytic performances in the n-regioselective hydroformylation of n-octenes and 2-pentene, from which the 3,5-di-t-butyl-substituted ligand offered a higher n-regioselectivity accompanied by a lowering of the reaction rate in comparison to the parent ligand L1.
- Zhang, Baoxin,Jiao, Haijun,Michalik, Dirk,Klo?, Svenja,Deter, Lisa Marie,Selent, Detlef,Spannenberg, Anke,Franke, Robert,B?rner, Armin
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p. 7554 - 7565
(2018/05/23)
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- Synthesis of H-Phosphonate Intermediates and Their Use in Preparing the Herbicide Glyphosate
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The esterfication of hypophosphorous acid is followed by reaction with another molecule of alcohol under the action of a nickel catalyst to provide a green method for the preparation of H-phosphonate diesters. This method avoids the need for any stoichiometric chlorine unlike those based on phosphorous trichloride.
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Paragraph 0036; 0056
(2014/10/16)
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- Organophosphorus chemistry without PCl3: A bridge from hypophosphorous acid to H-phosphonate diesters
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A process for the conversion of hypophosphorous acid (H3PO 2, HPA) and alcohols into various H-phosphonate diesters [(RO) 2P(O)H] is described. The new reaction provides a missing bridge between HPA and important H-phosphonates, completely avoiding the use of PCl3. Nickel chloride or nickel on silica catalyze the oxidative phosphorylation of alkyl phosphinates with various alcohols or water. The reaction is atom economic and avoids the formation of waste products. The previous need for both chlorine and base is completely avoided. Esterification of hypophosphorous acid followed by reaction with another molecule of alcohol under the action of a nickel catalyst provides a green method for the preparation of H-phosphonates. This method entirely avoids the need for any stoichiometric chloride unlike those based on phosphorus trichloride. Copyright
- Fisher, Henry C.,Prost, Lucie,Montchamp, Jean-Luc
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p. 7973 - 7978
(2014/01/06)
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- Stable electrodes with modified work functions and methods for organic electronic devices
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One embodiment is a method, comprising: depositing a molecule on an electrode, wherein the electrode has a surface and the molecule has a binding group (e.g., an anchoring group) that binds to the surface, thereby providing a work function that is stable for at least 100 hours under ambient conditions.
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- Functionalized matrixes for dispersion of nanostructures
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Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes are optionally formed from the ligands. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.
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- Synthesis, characterization and hydrolysis of osmium tetraphosphorus complexes
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The reaction of [CpOs(PPh3)2Cl] (1) with one equivalent of white phosphorus in the presence of AgOTf (OTf = triflate, OSO2CF3) as chloride scavenger affords the stable metal complex [CpOs(PPh3)2
- Caporali, Maria,Di Vaira, Massimo,Peruzzini, Maurizio,Costantini, Stefano Senior,Stoppioni, Piero,Zanobini, Fabrizio
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p. 152 - 158
(2010/04/01)
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- Oxidation of lower oxyacids of phosphorus by tetraethylammonium chlorochromate: A kinetic and mechanistic study
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Oxidation of lower oxyacids of phosphorus by tetraethylammonium chlorochromate in dimethyl sulphoxide leads to the formation of corresponding oxyacids with phosphorus in a higher oxidation state. The reaction exhibits 1:1 stoichiometry. The reaction is first order each with respect to chlorochromate and the oxyacids. The reaction does not induce polymerization of acrylonitrile. The oxidation of deuterated phosphinic and phosphorous acids exhibits a substantial primary kinetic isotope effect. The oxidation has been studied in nineteen different organic solvents. The effect of solvent indicates that the solvent polarity plays a major role in the process. It has been shown that the pentacoordinated tautomer of the phosphorus oxyacid is the reactive reductant and the tricoordinated form of phosphorus oxyacids does not participate in the oxidation process. A mechanism involving transfer of a hydride ion in the rate determining step has been proposed.
- Vadera, Khushboo,Sharma,Agarwal,Sharma, Pradeep K.
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p. 302 - 306
(2011/01/10)
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- Coordination and reactivity of white phosphorus and tetraphosphorus trisulphide in the presence of the fragment CpFe(dppe) [dppe = 1,2-bis(diphenylphosphino)ethane]
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The reaction of [CpFe(dppe)Cl] (1) [dppe = 1,2-bis(diphenylphosphino)ethane] with one equivalent of P4 or P4S3 in the presence of a chloride scavenger, TlPF6 or AgOTf (OTf = triflate, OSO2CF3), affords the complexes [CpFe(dppe)(η1-P4)]PF6 (2) and [CpFe(dppe)(η1-Pbasal-P4S3)]OTf (3) which contain the tetrahedral P4 and the mixed P4S3 cage molecule η1-bound to the metal. Both P4 and P4S3 yield furthermore the dimetal compounds [{CpFe(dppe)}2(μ,η1:1-P4)](PF6)2 (4) and [{CpFe(dppe)}2(μ,η1:1-Papical-Pbasal-P4S3)](OTf)2 (5), which contain the tetrahedral P4 or the mixed-cage P4S3 molecule tethering two ruthenium fragments via two phosphorus atoms. All the compounds have been characterized by elemental analyses and NMR measurements. The crystal structure of 4 has been determined by X-ray diffraction methods. The complexes readily react with excess water under mild reaction conditions and the outcoming products have been identified.
- Di Vaira, Massimo,Peruzzini, Maurizio,Costantini, Stefano Seniori,Stoppioni, Piero
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p. 816 - 820
(2010/06/16)
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- Activation and transformation of white phosphorus by palladium(ii) complexes
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A reaction of bis(triphenylphosphine)palladium dibromide with white phosphorus in the presence of NaBPh4 selectively gives phosphorous acid H3PO3. The mechanism of the formation involves coordination of a white phosphorus molecule, ligand exchange, and hydrolysis of the coordinated P4 molecule in the coordination sphere of palladium.
- Kagirov,Voloshin,Rizvanov, I. Kh.,Sinyashin,Yakhvarov
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p. 1116 - 1118
(2011/02/16)
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- Getting a clue to the hydrolytic activation of white phosphorus: The generation and stabilization of P(OH)2PHPHPH(OH) at ruthenium centers
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The bimetallic compound [{CpRu(PPh3)2} 2(μ,η1:1-P4)][CF3SO 3]2, in which the tetrahedral P4 is bound to two CpRu(PPh3)2 fragments, slo
- Barbaro, Pierluigi,Di Vaira, Massimo,Peruzzini, Maurizio,Costantini, Stefano Seniori,Stoppioni, Piero
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p. 1091 - 1096
(2009/04/25)
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- Oxidation of white phosphorus by peroxides in aqueous and alcoholic solutions: mechanistic aspects and catalytic studies
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The oxidation of white phosphorus by hydrogen peroxide or different organic peroxides (such as tert-butyl hydroperoxide, dibenzoylperoxide, 3-chloroperoxybenzoic acid) has been studied in both aqueous and alcoholic solutions under anaerobic conditions. De
- Akbayeva, Dina N.,Faisova, Farida Kh.,Abdreimova, Rumia R.,Peruzzini, Maurizio
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p. 181 - 193
(2008/10/09)
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- Inorganic boranophosphate salts
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The invention provides novel inorganic boranophosphate salts that can be used as fertilizers, in detergent formulations, as additive in melts for the glass industry, in boron neutron-capture therapy of cancer, and as synthetic building blocks in the synthesis of boranonucleotides of various lengths.
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Page/Page column 4; 7
(2008/06/13)
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- Method and compositions for identifying anti-HIV therapeutic compounds
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Methods are provided for identifying anti-HIV therapeutic compounds substituted with carboxyl ester or phosphonate ester groups. Libraries of such compounds are screened optionally using the novel enzyme GS-7340 Ester Hydrolase. Compositions and methods relating to GS-7340 Ester Hydrolase also are provided.
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- Process for the preparation of N-phosphonomethylglycine and derivatives thereof
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N-phosphonomethylamines are produced by reaction of an amine substrate with a halomethylphosphonic acid or salt thereof, a hydroxymethylphosphonic acid or salt thereof, or a dehydrated self-ester dimer, trimer or oligomer of hydroxymethylphosphonic acid. Among the products that may be prepared according to the process are N-phosphonomethylaminocarboxylic acids such as (e.g.) glyphosate, N-phosphonomethylaminoalkanols such as (e.g.) hydroxyethlaminomethylphosphonic acid, and N-acylaminomethylphosphonic acids such as (e.g.) N-carbamylaminomethylphosphonic acid. Certain reactions are conducted with a substantial excess of amine reactant in order to drive the conversion while avoiding excessive formation of bis(N-phosphonomethyl)amine by-products. Other reactions use a secondary amine substrate (such as iminodiacetic acid) and can be conducted at substantial equimolar ratios of halomethylaminomethylphosphonic acid or hydroxyaminomethylphosphonic acid to secondary amine reactant without significant formation of bis(phosphonomethyl)amine by-products. Further disclosed is a process for the preparation of hydroxymethylphosphonic acid self-ester dimers, trimers and oligomers by azeotropic dehydration.
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Page/Page column 30
(2010/02/11)
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- Biologically active 4H-benzo [1,4] oxazin-3-ones
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The invention is directed to 4h-benzo[1,4]oxazin-3-ones useful as peroxisome proliferator activated receptor gamma (PPARγ) agonists or antagonists. Pharmaceutical compositions comprising compounds of the present invention and methods of treating conditions such as NIDDM and obesity are also disclosed.
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- Method and compositions for identifying anti-HIV therapeutic compounds
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Methods are provided for identifying anti-HIV therapeutic compounds substituted with carboxyl ester or phosphonate ester groups. Libraries of such compounds are screened optionally using the novel enzyme GS-7340 Ester Hydrolase. Compositions and methods relating to GS-7340 Ester Hydrolase also are provided.
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- Antiviral compounds
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This invention relates to purine compounds of formula (I): R1 is NH2 or OH; R2 is H or NH2; R3 is H or alkyl; each of m and n, independently, is 1, 2, 3, or 4; X is O, S, or NH; and Y is H, halogen, ORa, P(O)(ORa)2, or P(O)(ORa)(ORb), in which Ra is H, alkyl, aryl, heteroaryl, cyclyl, heterocyclyl, and Rb is wherein A is adenine, guanine, cytosine, uracil, or thymine; Rc is H or OH; Rd is H or alkyl; Re is H, alkyl, or 5-ethylidene-(3,4-dialkoxyl)-furan-2-one; provided that if R1 is NH2, R2 is H; and if R1 is OH, R2 is NH2.
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- Method of treating attention deficit hyperactivity disorder
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This invention relates to a method of treating ADHD by administering an alpha2delta ligand such as, for example, gabapentin or pregabalin, or a pharmaceutically acceptable salt thereof.
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- Reconsideration of the base-free batch-wise esterification of phosphorus trichloride with alcohols
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Batch-wise esterification of phosphorus trichloride with different alcohols in the absence of base and cleavage of the reaction products by the HCl released in course of the reaction were reinvestigated. The role of the kind of alcohol, mixing order of reagents, temperature, time of reaction, and excursion of gaseous HCl in the proportional composition of the reaction products were studied. Considering the mechanism of esterification and cleavage of the products, the optimized conditions to retain the cleavage process and high-yield production of dialkyl hydrogen phosphonates were determined.
- Fakhraian,Mirzaei
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p. 401 - 404
(2013/09/05)
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- Method of treating tinnitus
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The invention relates to a method of treating tinnitus by administering an alpha2delta ligand such as, for example, a compound of Formula and pharmaceutically acceptable salts thereof, wherein R1 is hydrogen or straight or branched lower alkyl, and n is an integer of from 4 to 6.
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- Biologically active 4H-benzo [1,4] oxazin-3-ones
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The invention is directed to 4h-benzo[1,4]oxazin-3-ones useful as peroxisome proliferator activated receptor gamma (PPARgamma) agonists or antagonists. Pharmaceutical compositions comprising compounds of the present invention and methods of treating conditions such as NIDDM and obesity are also disclosed.
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- Thermal disproportionation of hypophosphorous acid
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Thermal disproportionation of hypophosphorous acid was studied to find the reaction order, the rate constant and activation energy of the process, and also the temperature ranges in which the reaction rate is the highest.
- Shechkov,Pevneva,Meshkova
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p. 1354 - 1355
(2007/10/03)
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- Kinetics and mechanism of oxidation of lower oxyacids of phosphorus by tetrabutylammonium tribromide
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Oxidation of lower oxyacids of phosphorus by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of corresponding oxyacids with phosphorus in a higher oxidation state. The reaction exhibits 1:1 stoichiometry. The reaction is first order each in [TBATB] and [oxyacids]. The reaction does not induce polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is tribromide ion. It has been shown that the pentacoordinated tautomer of the phosphorus oxyacid is the reactive reductant. The oxidation of deuteriated oxyacids exhibits a substantial primary kinetic isotope effect. The effect of solvent composition indicates that the rate increases with an increase in the polarity of the solvent. A mechanism involving transfer of a hydride ion in the rate-determining step has been proposed.
- Sharma, Pradeep K
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p. 1612 - 1615
(2007/10/03)
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- Biologically active 4H-benzo [1,4]oxazin-3-ones
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The invention is directed to 4h-benzo[1,4]oxazin-3-ones useful as peroxisome proliferator activated receptor gamma (PPARγ) agonists or antagonists. Pharmaceutical compositions comprising compounds of the present invention and methods of treating conditions such as NIDDM and obesity are also disclosed.
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- Phosphonic acid derivatives as inhibitors of protein tyrosine phosphatase 1B (PTP-1B)
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The invention encompasses the novel class of compounds represented by formula I, which are inhibitors of the PTP-1B enzyme. The invention also encompasses pharmaceutical compositions and methods of treating or preventing PTP-1B mediated diseases, including diabetes, obesity, and conditions related to diabetes.
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- Antiviral agents and methods of treating viral infections
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The present invention relates to methods of treating viral or fungal infections using 3-aminopyridine-2-carboxyaldehyde thiosemicarbazone (3-AP) and 3-amino-4-methylpyridine-2-carboxaldehyde thiosemicarbazone (3-AMP) and its prodrug forms and to pharmaceutical compositions comprising these compounds.
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- Method of treating cartilage damage
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The invention relates to a method of preventing or treating cartilage damage by administering a GABA analog such as, for example, a compound of Formula 1and pharmaceutically acceptable salts thereof, wherein R1 is hydrogen or straight or branched lower alkyl, and n is an integer of from 4 to 6.
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- Modified prodrug forms of AP/AMP
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The present invention relates to compounds according to the structure: Where R is H or CH3; R2 is phosphate which can be free acid or salt; R3 is H, F, Cl, Br, I, OCH3, OCF3, CF3 or a C1-C3 alkyl group; R4 is H, F, Cl, Br, I, OCH3, OCF3 or CF3; and R5 and R6 are each independently H, F, Cl, Br, I, OCH3, OCF3 or CF3, with the proviso that when any two of R3, R4, R5 or R6 are other than H, the other two of R3, R4, R5 or R6 are H which may be used to treat neoplasia, including cancer.
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- SUBSTITUTED CYCLOALKANECARBOXYLIC ACID DERIVATIVES AS MATRIX METALLOPROTEASE INHIBITORS
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Inhibitors for matrix metalloproteases, pharmaceutical compositions containing them, and a process for using them to treat a variety of physiological conditions. The compounds of the invention have the generalized formula STR1 wherein each T is a substituent g roup; x is 0, 1, or 2; the group D represents STR2 the subscript "e" is 2 or 3; the group R 14 represents a variety of possible substituent groups of the cycloalkyl ring between D and G; the subscript "k" is 0-2; and the group G represents M, STR3 in which M represents--CO 2 H,--CON(R 11) 2, or--CO 2 R 12 ; and R 13 represents any of the side chains of the 19 noncyclic occurring amino acids. "
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- Therapeutic use of 1-amino-3-(N,N-dimethylamino)-propylidene-1,1-bisphosphonic acid and its salts
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Use of 1-amino-3-N,N-dimethylamino)-propyliden-1,1-bisphosphonic acid of the structural formula: STR1 or of its monosodium or other pharmaceutically acceptable salt, as a biological carrier for bone active substances or for the preparation of a medicament for the diagnosis, prophylaxis and/or treatment of bone and/or mineral metabolism disorders.
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- Benzo[f]quinoxalinedione derivatives, their production and use in pharmaceutical agents
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Compounds of formula I STR1 are described, in which substituents R 1 -R 4 have the meanings mentioned in the application as well as their production and use in pharmaceutical agents.
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- Coconjugates of OMPC, HIV related peptides and anionic moieties
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A novel coconjugate comprising an immunogenic protein or protein complex having a first set of covalent linkages to low molecular weight moieties, --a--, which have an anionic or polyanionic character at physiological pH, and a second set of covalent linkages to peptides comprising Human Immunodeficiency Virus (HIV) Principal Neutralizing Determinants (PNDs), or peptides immunologically equivalent therewith, is useful for inducing anti-peptide immune responses in mammals, for inducing HIV-neutralizing antibodies in mammals, for formulating vaccines to prevent HIV infection or disease, including the Acquired Immune Deficiency Syndrome (AIDS), or for treating humans afflicted with HIV infection or disease.
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- PROTEIN FARNESYL TRANSFERASE INHIBITORS
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Inhibition of farnesyl transferase, which is an enzyme involved in ras oncogene expression, and inhibition of cholesterol biosynthesis, are effected by compounds of the formula: their enantiomers, diastereomers, and pharmaceutically acceptable salts, prodrugs, and solvates, wherein: X is -ONR1C(O)-, -N(OR1)C(O)-, -NR1C(O)-, -C(O)NR1-, -NR1S(O2)-, -C(O)O-, -OC(O)-, -O-, -NR1- or -(S)q; Y and Z are each independently -CO2R2, -SO3R2 or P(O)(OR2)(OR3); R is alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkenylene or aryl; R1, R2 and R3 are each independently hydrogen, alkyl, aryl or aralkyl; m and n are each independently 0 or an integer from 1 to 5; p is 0 or 1; and q is an integer from 1 to 2.
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- Phosphonates as anti-cancer agents
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This invention pertains to the synthesis and usc as anti-cancer therapeutic agents of a group of substances with a glycerol backbone linked to phosphonocholinc, or other phosphorus-containing head groups, of the following formula: STR1 wherein n is 0 to 14 and R1 is an alkyl group containing 12 to 20 carbon atoms, R2 is a methyl group, n=0 to 14 and m=2 to 10, or enantiomer thereof, or mixture of stereoisomers. This invention also pertains to the following formula: STR2 wherein n is 15 to 17; R1 is an alkyl group: m is 0 to 2; T is an oxygen atom or a methylene; and R2 is a choline group and therapeutically effective pharmaceutically acceptable salts thereof. These thiophosphonolipids are useful for treating cancer in a mammal in need of cancer treatment.
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- Oxygen-Transfer Reactions of Methylrhenium Oxides
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Methylrhenium dioxide, CH3ReO2 (or MDO), is produced from methylrhenium trioxide, CH3ReO3 (or MTO), and hypophosphorous acid in acidic aqueous medium. Its mechanism is discussed in light of MTO's coordination ability and the inverse kinetic isotope effect (kie): H2P(O)OH, k = 0.028 L mol-1 s-1; D2P(O)OH, k = 0.039 L mol-1 s-1. The Re(V) complex, MDO, reduces perchlorate and other inorganic oxoanions (XOn-, where X = Cl, Br, or I and n = 4 or 3). The rate is controlled by the first oxygen abstraction from perchlorate to give chlorate, with a second-order rate constant at pH 0 and 25°C of 7.3 L mol-1 s-1. Organic oxygen-donors such as sulfoxides and pyridine N-oxides oxidize MDO to MTO as do metal oxo complexes: V(aq)2+, VO2+(aq), HOMoO2+(aq), and MnO4-. The reaction between V(aq)2+ with MTO and the reduction of VO2+ with MDO made it possible to determine the free energy for MDO/MTO. Oxygen-atom transfer from oxygen-donors to MDO involves nucleophilic attack of X-O on the electrophilic Re(V) center of MDO; the reaction proceeds via an [MDO-XO] adduct, which is supported by the saturation kinetics observed for some. The parameters that control and facilitate the kinetics of such oxygen-transfer processes are suggested and include the force constant for the asymmetric stretching of the element-oxygen bond.
- Abu-Omar, Mahdi M.,Appelman, Evan H.,Espenson, James H.
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p. 7751 - 7757
(2008/10/09)
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- Methods for the synthesis of phosphonate esters
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Phsophonate esters can be synthesized in high yields by condensations of alcohols with methyl phosphonates followed by selective demethylation. The reaction is general, relativly insensitive to steric constraints of hindered phosphonic acids, and can also be carried out on a solid support to synthesize large collections of compounds to screen for pharmacological activity.
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- FARNESYL: PROTEIN TRANSFERASE INHIBITORS AS ANTICANCER AGENTS
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The present invention relates to certain inhibitors of farnesyl: protein transferase which are useful as antineoplastic agents.
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- 2-piperidinecarboxylic acid derivatives useful as NMDA receptor antagonists
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Compounds of formula I STR1 wherein X is STR2 or N--O--, in which R 4 is hydrogen or halogen, R 1, R 2, and R 3 independently represent hydrogen or a C 1-4 alkyl group, and n has a value of zero to four are disclosed. Also disclosed are pharmaceutically acceptable salts of these compounds, pharmaceutical compositions of these compounds or salts with a pharmaceutically acceptable carrier, the use of these materials as N-methyl-D-aspartate receptor antagonists, processes for preparing these compounds and salts, and methods to treat cerebral diseases by administering an effective amount of these compounds, salts or compositions.
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- LOW-TEMPERATURE OXIDATION OF RED PHOSPHORUS
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The oxidation kinetics of red phosphorus in the low-temperature region have been investigated, and conditions favorable for the accumulation of various oxidation products (H3PO2, H3PO3, and H3PO4) have been determined.
- Shechkov, G. T.,Domin, A. V.,Neskorodova, N. M.
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p. 1501 - 1504
(2007/10/02)
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- Kinetics and Mechanism of the Oxidation of Phosphinic, Phenylphosphinic and Phosphorous Acids by Bromine
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Oxidation of lower oxyacids of phosphorus by aqueous bromine has been studied in the +> range 0.001 - 5.0 mol dm-3.The reaction is first order with respect to bromine and the oxyacid.Molecular bromine has been postulated as the reactive oxidising species.Oxidation of deuteriated phosphinic and phosphorous acids exhibited substantial kinetic isotope effect.A study of +> variation showed the oxy-anion is oxidised much more rapidly than the parent acid.It is proposed that the 'inactive' tautomer of the oxyacid participates in the oxidation process.A suitable mechanism has been suggested.
- Agarwal, Saraswati,Mathur, Abha,Banerji, Kalyan K.
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p. 433 - 436
(2007/10/02)
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- Substituted alpha-amino acids having pharmaceutical activity
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The present invention is novel substituted α-amino acids, pharmaceutical compositions, method of use, and preparations therefore having utility for treating disorders which benefit from blockade of aspartate and glutamate receptors.
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- HMG-COA REDUCTASE INHIBITORS
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Disclosed are novel substituted cyclohexenyl phosphinylhydroxybutyrates as 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors useful as antihypercholesterolemic agents represented by the formula: STR1 and pharmaceutically acceptable salts ther
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