- Phosphine-catalyzed addition of P(O)-H compounds to ethyl phenylpropiolate
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An efficient PBu3-catalyzed α-addition of the P(O)-H bond to ethyl phenylpropiolate has been developed. This strategy offers a facile method for the preparation of synthetically useful alkenyl phosphonates and phosphinates proceeding under neut
- Salin, Alexey V.,Il'in, Anton V.,Shamsutdinova, Fanuza G.,Fatkhutdinov, Albert R.,Galkin, Vladimir I.,Islamov, Daut R.,Kataeva, Olga N.
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- Novel dialkylphosphorylhydrazones: Synthesis, leishmanicidal evaluation and theoretical investigation of the proposed mechanism of action
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As part of a program to develop new drugs for the treatment of neglected diseases, new dialkylphosphorylhydrazones were synthesized and evaluated against the trypanosomatid parasites Leishmania braziliensis and Leishmania amazonensis. The synthesis of these compounds proved satisfactory with yields ranging from moderate to good. The most active compounds against L. braziliensis presented IC50 values in the 10-2 μM range, similar to that of the reference drug pentamidine. Two compounds, 4m and 4n, showed a significant dose dependent decrease in the infection index of L. amazonensis infected macrophages and caused a complete healing of nodules and ulcers when tested in vivo against L. amazonensis-infected mice, but the control of parasite burden at the inoculation site was statistically significant only in the case of treatment with 4n. A target fishing (reverse docking) approach using molecular docking with 15 enzymes of L. braziliensis indicated that the probable target of the active compounds was hexokinase, the first enzyme of the glycolytic pathway.
- Da Matta, Carolina Barbosa Brito,De Queiroz, Aline Cavalcanti,Santos, Mariana Silva,Alexandre-Moreira, Magna Suzana,Gon?alves, Vinicius Tomaz,Del Cistia, Catarina De Nigris,Sant'Anna, Carlos Mauricio R.,DaCosta, Jo?o Batista N.
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- Continuous flow alcoholysis of dialkyl h-phosphonates with aliphatic alcohols
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The continuous flow alcoholysis of dialkyl H-phosphonates by aliphatic alcohols in the absence of a catalyst was elaborated using a microwave (MW) reactor equipped with a flow cell. By the precise control of the reaction conditions, the synthesis could be fine-tuned towards dialkyl H-phosphonates with two different and with two identical alkyl groups. In contrast to the “traditional” batch alcoholysis, flow approaches required shorter reaction times, and the products became available at a larger scale.
- Bálint, Erika,Tajti, ádám,Tóth, Nóra,Keglevich, Gy rgy
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- Remarkable structural effects on the complexation of actinides with H-phosphonates: A combined experimental and quantum chemical study
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The structural effects of the carbon chain on the extraction of actinides by organo-phosphorus extractants have been examined experimentally and by computation. Branched butyl H-phosphonates and their linear chain isomer, n-butyl H-phosphonate (DBHP), wer
- Chandrasekar, Aditi,Brahmmananda Rao,Sundararajan, Mahesh,Ghanty, Tapan K.,Sivaraman
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supporting information
p. 3841 - 3850
(2018/03/21)
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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; 0044; 0047
(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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- Electrophilic trifluoromethylation of S-hydrogen phosphorothioates
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A series of S-hydrogen phosphorothioates have been converted to the corresponding S-trifluoromethyl derivatives upon reaction with the electrophilic trifluoromethylation reagent 1 (trifluoromethyl 1,3-dihydro-3,3-dimethyl-1,2- benziodoxole). Relative rate data were obtained by 19F NMR monitoring of competition experiments and were evaluated by means of the Taft equation. A high positive polar sensitivity factor of 2.55 was found for electron-rich substrates and a negative one of -0.37 for electron-poor ones, implying the involvement of two different rate-determining steps. Furthermore, the reaction was found to be unaffected by steric factors.
- Santschi, Nico,Togni, Antonio
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experimental part
p. 4189 - 4193
(2011/07/31)
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- An efficient synthesis of O,O- di propyl (E)-2-[1-methyl 2-oxopropylidene]phosphorohydrazidothiolate (E) oxime and its analogues: A potential marine toxin
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An efficient method for the synthesis of Ptychodiscus brevis toxin O,O- di n-propyl (E)-2-[1-methyl 2-oxopropylidene]phosphorohydrazidothiolate (E) oxime (TG-1) and its analogues has been developed using thermally stable and recyclable silica gel and Na2SO4 as a condensing agent and water scavenger, respectively. The compounds were evaluated against fish Rasbora daniconius by determining the LC50 and LC90 values. The results of biological evaluation showed that these compounds have high degree of toxicity. Copyright Taylor & Francis Group, LLC.
- Gupta, Arvind K.,Dubey,Parashar,Kaushik
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scheme or table
p. 1892 - 1910
(2009/08/07)
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- Synthesis of O,O-dialkyl 2-oxo-2-(4-(selenomorpho-linosulfonyl)phenylamino) ethylphosphonate
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A series of O,O-dialkyl 2-oxo-2-(4-(seleomorpholinosulfonyl)phenylamino) ethy lphosphonate were synthesized by reactions of 2-chloro-N-(4- (seleomorpholino sulfonyl)phenyl)acetamide with dialkylphosphite in the presence of sodium hydride. The structure of all new compounds has been confirmed by 1H NMR,31P NMR, IR, Mass spectroscopy and elemental analyses. Copyright Taylor & Francis Group, LLC.
- Wang, Fang,Hu, Liming,Li, Xiaopeng,Xu, Xuemei,Du, Hongguang
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scheme or table
p. 610 - 616
(2009/04/11)
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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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- Synthesis of dialkyl phosphites and trialkyl phosphates by oxidation of sodium hypophosphite by copper(II) chloride
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Sodium hypophosphite oxidazies in alcoholic solution of CuCl2 at 50-80 deg C to give dialkyl phosphite and trialkyl phosphate.The yield of trialkyl phosphate increases with decreasing molecular weight of the alcohol and reaches ca. 100percent for MeOH and EtOH.The optimal conditions were found, and the mechanism of oxidation of NaPH2O2 to (RO)2PHO and (RO)3PO by copper(II) chloride was studied.The reaction proceeds via the formation of alkyl hypophosphite and copper(II) complexes with alkyl hypophosphite and dialkyl phosphite, which undergo inner-sphere two-electron redox decomposition with the liberation of dialkyl phosphite and trialkyl phosphate, respectively.
- Dorfman, Ya. A.,Aleshkova. M. M.
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p. 515 - 520
(2007/10/03)
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- ON THE INTERACTION BETWEEN HYPOPHOSPHOROUS ACID AND ALCOHOLS
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The esterification of hypophosphorous acid with alcohols, i.e. isopropanol, isobutanol, n-pentanol, n-octanol and 1,3-propylene glycol leads to the formation of the corresponding phosphonous acid esters in yields of up to 50percent, in addition to the hypophosphorous acid esters.The compounds are characterized by their elemental analyses, infrared and 1H NMR spectra.A mechanism of their formation is suggested.
- Devedjiev, I.,Ganev, V.,Stefanova, R.,Borisov, G.
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- Acylphosphonates: P-C Bond Cleavage of Dialkyl Acylphosphonates by Means of Amines. Substituent and Solvent Effects for Acylation of Amines
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Studies on the benzoylation of amines of dialkyl benzoylphosphonates (1A-F) were described in detail. Stoichiometric reactions of diethyl benzoylphosphonate (1B) with a variety of amines (2a-i) gave amides as the main products along with diethyl phosphonate (4B) and α-(phosphoryloxy)benzyl phosphonate (5B). The yields of amides increased with the ratio of 1B/2a-i. The use of hindered dialkyl benzoylphosphonates resulted in high yields of amides while the reaction rates decreased markedly. The benzoylations of n-propylamine (2d) with 1B in various solvents having dielectric constants of 1.9-36.7 were conducted. The yields of N-n-propylbenzamide (3d) and 5B were surprisingly almost constant. However, the reaction rates varied as follows. In nonpolar solvents such as n-hexane and cyclohexane benzoylation was remarkably rapid while the benzoylation in methylene chloride was much slower than that in other solvents used. Compound 1B underwent smooth reaction with aliphatic amines but did not react with aromatic amines under the same conditions. Selective N-benzoylation of the bifunctional amine, ethanolamine, was achieved by means of diisopropyl benzoylphosphonate (1C) in tetrahydrofuran. The use of the hindered dialkyl benzoylphosphonate 1C resulted in poorer yields of amides in the case of the reaction with a hindered amine such as diethylamine, but higher yields of amides in the case of primary amines. Addition of triethylamine and 4-(dimethylamino)pyridine (DMAP) slightly accelerated the benzoylation, but yields of amides were similar to those in the absence of the catalysts. Optimum conditions for high yields of amides were proposed for the practical use of dialkyl benzoylphosphonates as the acylating agents in the present reaction.
- Sekine, Mitsuo,Satoh, Masaki,Yamagata, Hikaru,Hata, Tsujiaki
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p. 4162 - 4167
(2007/10/02)
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