- P-Toluenesulfonic acid-Celite as a reagent for synthesis of esters of alkylphosphonic acids under solvent-free conditions
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The coupling reaction of alkylphosphonic acids and alcohols on the surface of p-toluenesulfonic acid-Celite under mild and solvent-free conditions gave the corresponding phosphonates in excellent yields. This method provides a useful rapid synthesis of phosphonates for use in the unambiguous identification of chemical warfare agents.
- Gupta, Arvind K.,Kumar, Rajesh,Dubey, Devendra K.,Kaushik
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p. 328 - 331
(2008/02/10)
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- Phase-transfer-catalyzed Michaelis-Becker synthesis of dialkyl methyl phosphonates
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A liquid-liquid phase-transfer-catalyzed (PTC) Michaelis-Becker reaction was adopted in the preparation of dialkyl methyl phosphonate (R=Me, iPr; nBu, and iBu). This was performed by the reaction of an appropriate dialkyl hydrogen phosphonate with methyl iodide in the presence of benzyl triethyl ammonium chloride and sodium hydroxide as PTC and base, respectively. A liquid-liquid two-phase system (H2O/CH2Cl2) introduced a suitable situation for the preparation of dialkyl methyl phosphonates with bulky alkyl groups (R=iPr, nBu, and iBu), but with R=Me, the hydrolysis of dimethyl hydrogen phosphonate (reagent) reduced the yield to 22%. In this case, a solid-liquid PTC-free system was successfully applied and yield of over 80% was obtained. Copyright Taylor & Francis Group, LLC.
- Fakhraian, Hossein,Mirzaei, Akbar
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p. 511 - 518
(2007/10/03)
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- Analogues with fluorescent leaving groups for screening and selection of enzymes that efficiently hydrolyze organophosphorus nerve agents
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Enzymes that efficiently hydrolyze highly toxic organophosphorus nerve agents could potentially be used as medical countermeasures. As sufficiently active enzymes are currently unknown, we synthesized twelve fluorogenic analogues of organophosphorus nerve agents with the 3-chloro-7-oxy-4- methylcoumarin leaving group as probes for high-throughput enzyme screening. This set included analogues of the pesticides paraoxon, parathion, and dimefox, and the nerve agents DFP, tabun, sarin, cyclosarin, soman, VX, and Russian-VX. Data from inhibition of acetylcholinesterase, in vivo toxicity tests of a representative analogue (cyclosarin), and kinetic studies with phosphotriesterase (PTE) from Pseudomonas diminuta, and a mammalian serum paraoxonase (PON1), confirmed that the analogues mimic the parent nerve agents effectively. They are suitable tools for high-throughput screens for the directed evolution of efficient nerve agent organophosphatases.
- Brise?o-Roa, Luis,Hill, Jim,Notman, Stuart,Sellers, David,Smith, Andy P.,Timperley, Christopher M.,Wetherell, Janet,Williams, Nichola H.,Williams, Gareth R.,Fersht, Alan R.,Griffiths, Andrew D.
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p. 246 - 255
(2007/10/03)
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- Surface-mediated solid phase reactions: A simple, efficient and base-free synthesis of phosphonates and phosphates on Al2O3
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Al2O3-supported solvent free condensation of alkylphosphonic dichlorides with alcohols at room temperature yielded phosphorus esters in excellent yields.
- Acharya, Jyotiranjan,Shakya, Purushottam D.,Pardasani, Deepak,Palit, Meehir,Dubey, Devendra K.,Gupta, Arvind K.
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p. 194 - 196
(2007/10/03)
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- Oligophosphonic acids, oligophosphinic acids, and process of preparation
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This invention relates to a process for preparing oligophosphonic or oligophosphinic acids or esters or salts thereof which comprises reacting an alkali metal ester of phosphorous acid or an alkali metal ester of arylphosphonous or alkylphosphonous acid with an olefin polyhalide and, optionally, saponifying the resultant product.
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