- Catalytic hydrolysis of phosphate esters in microemulsions
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We have continued our kinetics investigation of the iodosobenzoate (IBA) catalysis of the hydrolysis of p-nitrophenyl diphenyl phosphate (PNDP), in microemulsion media composed of hexadecane in water stabilized by cetyltrimethylammonium bromide and 1-butanol over a range of water mass fractions. We have examined two iodosobenzoic acid derivatives (5-nitro-2-iodosobenzoic acid and 5-octyloxy-2-iodosobenzoic acid) as catalysts. In addition, we have determined by31P FT-NMR techniques that the major product of the hydrolysis of PNDP, both in IBA catalyzed and in uncatalyzed media, is diphenylphosphate.
- Knier, Barry L.,Dupont Durst,Burnside, Beth A.,Mackay, Raymond A.,Longo, Frederick R.
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Read Online
- Synthesis of diaryl phosphates using orthophosphoric acid as a phosphorus source
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This paper presents a new synthetic route for diaryl phosphate esters, which are traditionally synthesized from phosphorus oxychloride. Specifically, we report the synthesis of diaryl phosphates by the dehydrative condensation of orthophosphoric acid, a phosphorus source, with aromatic alcohols.
- Tran, Cong Chi,Asao, Kazuya,Sasaki, Takeshi,Hayakawa, Yasuyuki,Kawaguchi, Shin-ichi
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supporting information
(2022/04/09)
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- Mesoporous cerium oxide for fast degradation of aryl organophosphate flame retardant triphenyl phosphate
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Cerium oxide nanoparticles were prepared by calcination of basic cerous carbonate (as a precursor) obtained by precipitation from an aqueous solution. Prepared samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), high resolution scanning electron microscopy (HRSEM), BET (Brunauer-Emmett-Teller) surface area and porosity measurement. Prepared cerium oxide was applied as a destructive sorbent for the fast and safe degradation of organophosphorus flame retardant triphenyl phosphate (TPP). It was shown that cerium dioxide was effective in the decomposition of TPP by cleavage of the P-O-aryl bond in the flame retardant molecule. A degradation mechanism for TPP on the ceria surface was proposed. The degradation is governed by conversion of TPP via diphenyl phosphate (DPP) to the final product identified as phenol (Ph). The key parameter increasing the degradation efficiency of CeO2 is the temperature of calcination. At optimum calcination temperature (500 °C), the produced ceria retains a sufficiently high surface area and attains an optimum degree of crystallinity (related to a number of crystal defects, and thus potential reactive sites). The fast and efficient degradation of organophosphorus flame retardant TPP was observed in a polar aprotic solvent (acetonitrile) that is miscible with water.
- Ederer, Jakub,??astny, Martin,Do?ek, Marek,Henych, Ji?í,Jano?, Pavel
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p. 32058 - 32065
(2019/10/21)
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- O -Phthalaldehyde catalyzed hydrolysis of organophosphinic amides and other P(O)-NH containing compounds
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Over 50 years ago, Jencks and Gilchrist showed that formaldehyde catalyses the hydrolysis of phosphoramidate through electrophilic activation, induced by covalent attachment to its nitrogen atom. Given our interest in the use of aldehydes as catalysts, this work was revisited to identify a superior catalyst, o-phthalaldehyde, which facilitates hydrolyses of various organophosphorus compounds bearing P(O)-NH subunits under mild conditions. Interestingly, chemoselective hydrolysis of the P(O)-N bonds could be accomplished in the presence of P(O)-OR bonds.
- Li, Bin-Jie,Simard, Ryan D.,Beauchemin, André M.
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supporting information
p. 8667 - 8670
(2017/08/10)
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- Neodymium tris-diarylphosphates: Systematic study of the structure-reactivity relationship in butadiene and isoprene polymerisation
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The catalytic properties of neodymium tris-phosphates with various diarylphosphate ligands in the stereoregular 1,4-cis-polymerisation of butadiene and isoprene were studied. The considerable variability of the diaryl phosphate structure allowed for the systematic investigation of the dependence of the catalytic properties of neodymium tris-diarylphosphates on the electronic and steric properties of the ligand. Electron-withdrawing substituents (F, Cl, Br) in the aryl moiety increased the catalyst activity of tris-diarylphosphate. Neodymium aryl phosphates containing lipophilic bulky ligands provided the synthesis of polydienes with a monomodal molecular-weight distribution. The optimal catalytic properties demonstrated that the neodymium aryl phosphate prepared from bis(2,6-dimethyl-4-tert-butylphenyl)-phosphoric acid showed high activity and ensured a monomodal MWD of polydienes (Mw/Mn ~ 2 for polybutadiene and Mw/Mn ~ 3 for polyisoprene) in various conditions.
- Nifant'Ev, Ilya E.,Tavtorkin, Alexander N.,Korchagina, Sof'Ya A.,Gavrilenko, Inna F.,Glebova, Nataliya N.,Kostitsyna, Nataliya N.,Yakovlev, Vladimir A.,Bondarenko, Galina N.,Filatova, Marina P.
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p. 219 - 277
(2014/05/20)
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- NANOPARTICLE COMPOSITION AND ASSOCIATED METHODS THEREOF
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A nanoparticle composition is provided, wherein the composition comprises a nanoparticulate metal oxide; and a phosphorylated polyol comprising at least two phosphate groups. The polyol comprises one or more hydrophilic groups selected from the group consisting of polyethylene ether moieties, polypropylene ether moieties, polybutylene ether moieties, and combinations of two or more of the foregoing hydrophilic moieties. A method of making the nanoparticle composition is also provided. The nanoparticle compositions provided by the present invention may be used as contrast agents in medical imaging techniques such as X-ray and magnetic resonance imaging.
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- DIAGNOSTIC AGENT COMPOSITION AND ASSOCIATED METHODS THEREOF
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A diagnostic agent composition is provided which comprises a nanoparticle composition and a pharmaceutically acceptable carrier or excipient. The nanoparticle composition comprises a nanoparticulate metal oxide and a phosphorylated polyol, wherein the phosphorylated polyol comprises at least two phosphate groups and one or more hydrophilic groups selected from the group consisting of polyethylene ether moieties, polypropylene ether moieties, polybutylene ether moieties, and combinations of two or more of the foregoing hydrophilic moieties. The disclosure provides detailed guidance on methods of making and using such diagnostic agent compositions. The diagnostic agent compositions provided by the present invention are useful as contrast agents for medical diagnostic imaging techniques such as magnetic resonance (MR) imaging and X-ray imaging. The diagnostic agent composition may be administered to a subject via a variety of techniques, among them injection, inhalation, and ingestion.
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- Novel photolabile protecting group for phosphate compounds
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A novel photolabile protecting group, thiochromone S,S-dioxide, containing the diazomethyl group for protection of phosphate derivatives is described. Deprotection of the successfully protected phosphate derivatives proceeded smoothly under photoirradiation using an ultrahigh-pressure mercury lamp to recover the corresponding phosphates quantitatively, and the photoproduct derived from the thiochromone derivative showed high fluorescence intensity. Georg Thieme Verlag Stuttgart · New York.
- Zhang, Youlai,Tanimoto, Hiroki,Nishiyama, Yasuhiro,Morimoto, Tsumoru,Kakiuchi, Kiyomi
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scheme or table
p. 367 - 370
(2012/03/11)
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- Synthesis, characterization and phosphotriesterase mimetic activity of some Zn(II) and Cu(II) complexes
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We report here the synthesis and characterization of a few phenolate-based ligands bearing tert- amino substituent and their Zn(II) and Cu(II) metal complexes. Three mono/binuclear Zn(II) and Cu(II) complexes [Zn(L1)(H 2O)].CH3OH.Hs
- Singh, Mamata,Butcher, Ray J.,Jasinski, Jerry P.,Golen, James A.,Mugesh, Govindasamy
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p. 1301 - 1313
(2013/06/04)
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- Catalytic synthesis of triaryl phosphates from white phosphorus
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Triaryl phosphates were synthesized from white phosphorus and phenols under aerobic conditions and in the presence of iron catalysts and iodine. Full conversion to phosphates was achieved without the use of chlorine, and the reactions do not produce acid waste. Triphenyl phosphate, tritolyl phosphate and tris(2,4-di-tert-butyl)phenyl phosphate were synthesized by this method with high selectivities. Various iron(III) diketonates were used to catalyze the conversion. Mechanistic studies showed that the reaction proceeds by formation of PI3, then O=PI(OPh)2 before the final formation of the phosphate. The nucleophilic substitution of O=PI(OPh)2 with phenol to form O=P(OPh)3 was found to be the rate-limiting step.
- Armstrong, Kenneth M.,Kilian, Petr
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experimental part
p. 2138 - 2147
(2011/06/28)
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- PHOTODISSOCIABLE PROTECTIVE GROUP
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The present invention provides a photolabile protecting group that can be removed by light irradiation under mild conditions. More specifically, the present invention provides a method comprising protecting a reactive functional group (e.g., a hydroxyl group, amino group, carboxyl group, carbonyl group, phosphodiester group, etc.) by the photolabile protecting group, and then removing the photolabile protecting group simply by light irradiation under neutral conditions. The present invention relates to a compound represented by Formula (3): wherein Ar1 is an optionally substituted aromatic or heteroaromatic ring, Ar2 is an optionally substituted aryl or heteroaryl group, X is a leaving group, and n is an integer of 1 or 2; and a method of protecting and deprotecting an amino group etc. using the compound.
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Page/Page column 41
(2011/02/25)
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- Hydrolysis of organophosphate esters: Phosphotriesterase activity of metallo-ss-lactamase and its functional mimics
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The phosphotriesterase (PTE) activity of a series of binuclear and mononuclear zinc(II) complexes and metallo-β-lactamase (mβl) from Bacillus cereus was studied. The binuclear complex 1, which exhibits good mβl activity, shows poor PTE activity. In contrast, complex 2, a poor mimic of mβl, exhibits much higher activity than 1. The replacement of Cl - ligands by OH- is important for the high PTE activity of complex 2 because this complex does not show any catalytic activi-ty in methanol. The natural enzyme mssl from B. cereus is also found to be an inefficient catalyst in the hydrolysis of phosphotriesters. These observations indicate that the binding of -lactam substrates at the binuclear zinc(II) center is different from that of phosphotriesters. Furthermore, phospho diesters, the products from the hydrolysis of triesters, significantly inhibit the PTE activity of mβl and its functional mimics. Although the mononuclear complexes 3 and 4 exhibited significant mβl activity, these complexes are found to be almost inactive in the hydrolysis of phosphotriesters. These observations indicate that the elimination of phosphodiesters from the reaction site is important for the PTE activity of zinc(II) complexes.
- Tamilselvi,Mugesh, Govindasamy
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experimental part
p. 8878 - 8886
(2010/11/02)
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- SULFONAMIDES AND PHARMACEUTICAL COMPOSITIONS THEREOF
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The invention is directed to a class of compounds, including the pharmaceutically acceptable salts of the compounds, having the structure of formula (I), as defined in the specification. The invention is also directed to compositions containing the compounds of formula (I).
- -
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Page/Page column 98
(2008/12/04)
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- Solid-phase synthesis of thermolytic DNA oligonucleotides functionalized with a single 4-hydroxy-1-butyl or 4-phosphato-/thiophosphato-1-butyl thiophosphate protecting group
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(Chemical Equation Presented) Several thermolytic CpG-containing DNA oligonucleotides analogous to 1 have been synthesized to serve as potential immunotherapeutic oligonucleotide prodrug formulations for the treatment of infectious diseases in animal models. Specifically, the CpG motif (GACGTT) of each DNA oligonucleotide has been functionalized with either the thermolabile 4-hydroxy-1-butyl or the 4-phosphato-/thiophosphato-1-butyl thiophosphate protecting group. This functionalization was achieved through incorporation of activated deoxyribonucleoside phosphoramidite 8b into the oligonucleotide chain during solid-phase synthesis and, optionally, through subsequent phosphorylation effected by phosphoramidite 9. Complete conversion of CpG ODNs hbu1555, psb1555, and pob1555 to CpG ODN 1555 (homologous to 2) occurred under elevated temperature conditions, thereby validating the function of these diastereomeric oligonucleotides as prodrugs in vitro. Noteworthy is the significant increase in solubility of CpG ODN psb1555 and CpG pob1555 in water when compared to that of neutral CpG ODN fma1555 (homologous to 1).
- Grajkowski, Andrzej,Ausin, Cristina,Kauffman, Jon S.,Snyder, John,Hess, Sonja,Lloyd, John R.,Beaucage, Serge L.
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p. 805 - 815
(2007/10/03)
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- Rapid phosphorus triester hydrolysis catalyzed by bimetallic tetrabenzimidazole complexes
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Bimetallic complexes based on the binucleating ligand N,N,N′, N′-tetrakis[(2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane ( 1L) and its new toluoyl ester derivative (2L) catalyze the hydrolysis of phosphorus triesters at ambie
- Klinkel, Kortney L.,Kiemele, Lauren A.,Gin, Douglas L.,Hagadorn, John R.
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p. 2919 - 2921
(2008/09/19)
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- PROCESS FOR PRODUCING CARBAPENEM COMPOUND FOR ORAL ADMINISTRATION
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The present invention provides a process for efficiently producing a 1β-methylcarbapenem compound for oral administration. The process, which is for producing a 1β-methylcarbapenem compound represented by general formula (2), is characterized by reacting a β-lactam compound represented by general formula (1) as a starting material with a thiol compound (R3-SH) in the presence of a base and optionally eliminating the protective group R1. In the formulae (1) and (2), R1 denotes a hydrogen atom, a trimethylsilyl group or a triethylsilyl group; R2 denotes an alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 10 carbon atoms; R3 denotes an organic group; and R4 denotes hydrogen, a trimethylsilyl group or a triethylsilyl group.
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Page/Page column 17
(2008/06/13)
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- Iodomethylzinc phosphates: Powerful reagents for the cyclopropanation of alkenes
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A new family of zinc carbenoids derived from phosphoric acids was developed and used in the cyclopropanation of allylic alcohols and ethers and also of unfunctionalized olefins. The use of the chiral phosphoric acid of a 3,3′-disubstituted BINOL leads to efficient stereocontrol, affording the cyclopropanes of allylic and homoallylic ethers with complete conversions and up to 93% ee. A catalytic version of this reaction using 10 mol % of the chiral phosphate reagent is also disclosed. Copyright
- Lacasse, Marie-Christine,Poulard, Cyril,Charette, Andre B.
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p. 12440 - 12441
(2007/10/03)
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- Process to prepare alkyl phenyl phosphates
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The present invention relates to a process to prepare dialkyl monophenyl phosphate, monoalkyl diphenyl phosphate or mixtures thereof wherein dichloromonophenyl phosphate and/or monochlorodiphenyl phosphate is reacted with an aliphatic alcohol in the presence of a Lewis acid catalyst and in the absence of solvent at a temperature of 40 to 200°C and a pressure of 0 to 1 bar. The present invention further relates to mixtures of monoalkyl diphenyl phosphates and dialkyl monophenyl phosphates obtainable from the above process and the use of such mixtures as a plasticiser and/or a flame retardant.
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Page/Page column 8-10
(2008/06/13)
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- Reactivity of polyethyleneimines in reversed and normal micellar solutions of surfactants
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The aminolysis and hydrolysis of 4-nitrophenyl esters of phosphorous-based acids in the poly(ethylene glycol) 600 monolaurate-polyethyleneimine-toluene and cationic surfactant-polyethyleneimine-water systems were studied by electronic spectrophotometry. R
- Zhil'tsova,Kudryavtsev,Zakharova,Lukashenko,Ryzhkina,Kudryavtseva
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p. 1853 - 1857
(2007/10/03)
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- Regioselective oxygenations of s-trans dienes, silyl dienol ethers (SDEs), by triphenyl phosphite ozonide (TPPO) and its mechanistic study
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The direct oxygenation of s-trans dienes, silyl dienol ethers (SDEs) 2, by triphenyl phosphite ozonide (TPPO) has been examined in detail. The regioselective oxygenation was found to give hydroperoxide 3, alcohol 4, ketone 5, dimer 6, and peroxy phosphate 7 with concomitant formation of triphenyl phosphate 8 and diphenyl trimethylsilyl phosphate 10. The formation of peroxy phosphate 7 was found for the first time in TPPO oxygenation reactions. The low temperature31P and1H NMR spectroscopic analyses proved the direct reaction of SDEs with TPPO without generation of singlet oxygen. The formation of the oxygenated products 3-7 is reasonably explained by the intervention of the zwitterion ZI, which can be formed by the nucleophilic attack of SDE to the central oxygen of the ozonide. The regioselective attack of SDE to the central oxygen of the ozonide was supported by the quantum chemical calculation (B3LYP/6-31G*).
- Mori,Abe,Nojima
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p. 3548 - 3553
(2007/10/03)
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- Nucleophilic substitution at a four-coordinate phosphorus atom. Reactivity of carboxylic acid amides toward diphenyl chlorophosphate in acetonitrile
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The kinetics of hydrolysis of diphenyl chlorophosphate in acetonitrile, catalyzed by carboxylic acid amides, was studied by conductometry at 25°C. Nucleophilic mechanism of the catalysis was established, and the rate constants for nucleophilic attack by carboxamide on the substrate were determined. Carboxylic acid amides with no substituent on the nitrogen turned out to be more active than N-mono-and N,N-disubstituted derivatives. This was explained by stabilization of the transition state through formation of hydrogen bond between the phosphinoyl oxygen atom and proton of the amino group. Cyclic amides showed a lower catalytic activity, as compared with acyclic analogs.
- Popov,Sadovskii,Solomoichenko,Savelova,Lobanova,Piskunova
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p. 715 - 724
(2007/10/03)
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- The reaction of 2-aminomethylphenols and their copper(II) complexes with esters of phosphorus acids
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2-Alkyl- and 2-dialkylaminomethylphenols (AMP) with different Hydrophobic substituents at the nitrogen atom and their copper(II) complexes (CAMP) react with the esters of phosphorus acids in aqueous solutions of ethanol in two stages: phosphorylated AMP (
- Ryzhkina,Kudryavtseva,Enikeev,Morozov,Boos,Sal'nikov
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p. 1349 - 1354
(2007/10/03)
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- Inter- and intramolecular pathways for the formation of tetrahydrofurans from β-(phosphatoxy)alkyl radicals. Evidence for a dissociative mechanism
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β-(Phosphatoxy)alkyl radicals generated by photolysis of Barton PTOC esters in the presence of allyl alcohol and tert-butyl mercaptan undergo nucleophilic substitution followed by 5-exo-trig radical ring closure leading to tetrahydrofurans in good yield and with high trans selectivity. β- (Phosphatoxy)alkyl radicals obtained by intramolecular hydrogen 1,5- abstraction with an alkoxyl radical undergo nucleophilic displacement providing tetrahydrofurans. The ensemble of results, including the effects of leaving groups and substituents, strongly support a dissociative mechanism for these radical nucleophilic displacement reactions.
- Crich, David,Huang, Xianhai,Newcomb, Martin
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p. 523 - 529
(2007/10/03)
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- Catalytic activity of aminomethylated calix[4]resorsinolarene aggregates in hydrolysis of esters of phosphorus acids
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The reaction kinetics of aminomethylated calix[4]resorcinolarenes (AMC) with p-nitrophenyl esters of phosphorus acids (EPA) in a water - DMF solution (30 vol.% DMF) was studied by spectrophotometry and 31P NMR spectroscopy in the presence and absence of the nonionic surfactant Triton X-100. The AMC form aggregates of micellar and nonmicellar types and are the catalysts for EPA hydrolysis. The catalytic activity of the aggregates depends on their structure, pH of the medium, and the nature of the solvent.
- Ryzhkina,Kudryavtseva,Babkina,Enikeev,Pudovik,Konovalov
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p. 1355 - 1359
(2007/10/03)
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- Substrate and stereochemical specificity of the organophosphorus acid anhydrolase from Alteromonas sp. JD6.5 toward p-nitrophenyl phosphotriesters
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The enzyme OPAA hydrolyzes p-nitrophenyl phosphotriesters bearing substituents at the phosphorus center ranging in size from methyl to phenyl. The enzyme exhibits stereoselectivity toward the hydrolysis of chiral substrates with a preference for the S(P)
- Hill, Craig M.,Wu, Feiyue,Cheng, Tu-Chen,Defrank, Joseph J.,Raushel, Frank M.
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p. 1285 - 1288
(2007/10/03)
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- β-(phosphatoxy)alkyl and β-(acyloxy)alkyl radical migrations studied by laser flash photolysis
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A number of β-(phosphatoxy)alkyl and β-(acyloxy)alkyl radicals have been generated by laser flash photolysis of the corresponding Barton PTOC esters. Time resolved studies permitted the determination of rate constants and kinetic parameters for their rearrangement in benzene, THF, and acetonitrile. Migrations are accelerated by electron-donating groups on the alkyl moiety, electron-withdrawing groups on the migrating group, and more polar solvents. All reactions showed strictly first order kinetics. The results are interpreted in terms of concerted mechanisms occurring through three electron, three center and five electron, five center mechanisms.
- Choi, Seung-Yong,Crich, David,Horner, John H.,Huang, Xianhai,Newcomb, Martin,Whitted, Patrick O.
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p. 3317 - 3326
(2007/10/03)
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- Long chain β-aminoethanols as micellar catalysts for the hydrolysis of diphenyl-p-nitrophenyl phosphate. The observation of an unusual enhancement of catalysis in the presence of added polyols
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The hydrolysis of p-nitrophenyldiphenyl phosphate (PNPDPP, 7) catalyzed by N-dodecylaminoethanol (6a), N-tetradecylaminoethanol (6b), N-methyl-N-tetradecylaminoethanol (6c), and N-hexadecylaminoethanol (6d) was investigated at 25°C at various pH values in aqueous media containing additives. Added ethanol or dimethoxyethane produces very little activity of 6a, b, c toward 7. The highest activities of 6a, b were found at pH 8.0 and 8.5 in solvents containing 20% glycerol or ethylene glycol. Under no conditions was N-hexadecylaminoethanol (6d) found to be active. The kinetics of the reaction of 6b with 7 were also investigated in a medium containing various amounts of glycerol, polyethylene glycol 400 (PEG 400), and water at pH 7.6-8.5. The best catalytic system comprised 3 mM 6b in 20% aqueous ethylene glycol, pH 8.5, which accelerated the hydrolysis of 7 by ~1700-fold over the blank rate. Kinetic experiments conducted using [7]/[6b] = 1 and 2 demonstrate that 6b exhibits true turnover catalysis. A mechanism for the catalyzed reaction is proposed.
- Oumar-Mahamat,Slebocka-Tilk,Brown
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p. 1577 - 1588
(2007/10/03)
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- Dephosphorylation and aromatic nucleophilic substitution in nonionic micelles. The importance of substrate location
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Reactions of OH- and F- with p-nitrophenyl diphenyl phosphate (pNPDPP) are inhibited by very dilute dodecyl (10) and (23) polyoxyethylene glycol (C12E10 and C12E23, respectively), but rate constants become independent of surfactant concentrations at concentrations above the critical micelle concentration. Low charge density anions, e.g., ClO4-, inhibit and low charge density cations, e.g., (n-C7H15)4N+, accelerate reactions, probably by controlling concentrations of nucleophiles in the palisade layer. Diphenyl phosphorofluoridate, generated by attack of F-, is not detected but is rapidly hydrolyzed to phenyl phosphorofluoridate or diphenyl phosphate ion with loss of phenol or F-. The products are different in DMSO containing modest amounts (- on the initial phosphorofluoridate. These differences are consistent with the micellar palisade layer being water-rich. Although the nonionic surfactants do not intervene nucleophilically in reactions of pNPDPP, considerable amounts of ether are formed in the reaction of 2,4-dinitrochlorobenzene (DNCB), in C12E10 and C12E23 at high pH by attack of alkoxide ion with the relatively hydrophilic DNCB located close to the micellar surface. The differences in the chemistries of reactions of pNPDPP and DNCB appear to be associated largely with differences in locations of these substrates in the nonionic micelles.
- Bunion, Clifford A.,Foroudian, Houshang J.,Gillitt, Nicholas D.,Whiddon, Christy R.
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p. 946 - 954
(2007/10/03)
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- Solvent effects on reactions of hydroxide and oximate ions with phosphorus(V) esters
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Second-order rate constants of reactions of OH-, 2,3-butanedionemonooximate and 2-hydroxybenzaldoximate ions with aryl phosphate, phosphinate and thioarylphosphinate esters go through minima with decreasing water content of aqueous acetonitrile, tert-butyl alcohol and N-methyl-2-pyrrolidone. For reactions in H2O-MeCN the solvent effects are analyzed in terms of activity coefficients of the anionic nucleophiles and transition states. In the drier solvents partial desolvation of the nucleophiles increases rates. Nucleophilicities of several oximates and inorganic anions are compared in water.
- Bunton, Clifford A.,Gillitt, Nicholas D.,Kumar, Anurag
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p. 221 - 228
(2007/10/03)
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- Nucleophilic substitution at a four-coordinate phosphorus atom. Reactivity of tertiary phosphine oxides toward diphenyl chlorophosphate in acetonitrile
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The kinetics of hydrolysis of diphenyl chlorophosphate in acetonitrile at 25°C, catalyzed by tertiary phosphine oxides, have been studied. At a water concentration of higher than 0.1 M, the reaction is of first order in the substrate and the catalyst and of zero order in water, which suggests nucleophilic catalysis of the hydrolysis with attack by the phosphine oxide on the substrate in the rate-determining stage. The rate constants for this stage are described by the Broonsted equation logk1 = -6.66 + 0.72pKaMeNO2. On the basis of the results obtained and previous data, phosphine oxides, despite similar basicities, were shown to be 10 times less reactive that pyridine N-oxides, and about 350 times more reactive that pyridines and imidazoles. 1996 MAEe Cyrillic signΚ Hayκa/Interperiodica Publishing.
- Sadovskii,Shvets,Solomoichenko,Savelova,Safaryan,Tsvetkov,Bondarenko
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p. 546 - 550
(2007/10/03)
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- Catalysis of the hydrolysis of esters of phosphorus acids by n-decylammonium chloride/n-decylamine mixed micelles
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The effect of n-decylammonium chloride/n-decylamine mixed micelles on the rate of hydrolysis of aryl esters of acids of four-coordinate phosphorus was studied spectrophotometrically. The shape of the concentration curves is characteristic of the micellar
- Bakeeva,Kudryavtseva,Bel'skii,Fedorov,Ivanov
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p. 1900 - 1903
(2007/10/03)
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- 9-Iodoso-10-phenanthroate: Structure and Phosphorolytic Properties of a Nonplanar Iodoxolone
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9-Iodoso-10-phenanthroic acid (IPA-OH) was prepared from 9-cyanophenanthrene in a four-step, 44percent overall yield synthesis, featuring cyano-directed ortho lithiation/iodination as the key step.An X-ray crystal structure showed that IPA-OH exsists in a
- Moss, Robert A.,Bracken, Kathryn,Emge, T. J.
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p. 7739 - 7746
(2007/10/03)
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- Acceleration of o-iodosobenzoate-catalyzed hydrolysis of p-nitrophenyl diphenyl phosphate by cationic polymer colloids
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Cross-linked polystyrene latexes containing (styrylmethyl)trialkylammonium chloride repeat units greatly accelerate the o-iodosobenzoate (IBA) catalyzed hydrolysis of p-nitrophenyl diphenyl phosphate (PNPDPP). The half-life of PNPDPP is as short as 3 s wi
- Lee, Jeng-Jong,Ford, Warren T.
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p. 3753 - 3759
(2007/10/02)
-
- REGIOSPECIFIC CONVERSION OF TERMINAL ALKYNES TO KETOL PHOSPHATES WITH AN IODINE(III)-PHOSPHATE REAGENT
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Terminal alkynes undergo regiospecific conversion to ketol phosphates when treated with the iodine(III)-phosphate 2 in acetonitrile containing water.
- Koser, Gerald F.,Chen, Xiao,Chen, Kuanchiang,Sun, Guoping
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p. 779 - 782
(2007/10/02)
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- NUCLEOPHILIC SUBSTITUTION AT THE TETRACOORDINATED PHOSPHORUS ATOM. COMPARISON OF THE REACTIVITY OF IMIDAZOLES, PYRIDINES, AND PYRIDINE N-OXIDES TOWARD DIPHENYL CHLOROPHOSPHATE IN ACETONITRILE
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The kinetics of the hydrolysis of diphenyl chlorophosphate in acetonitrile (MeCN) at 25 deg C, catalyzed by imidazoles and pyridines, were studied.In the range of water concentrations between 0.1 and 0.6 M the reaction has first order with respect to the substrate and the catalyst and zero order with respect to the water.This indicates a nucleophilic mechanism of catalysis where the rate-determining stage is attack by the amines on the substrate.The rate constants (k1, liter/mole*sec) for the reaction of the imidazoles and pyridines with diphenyl chlorophosphate are described by a common Broensted equation: log k1MeCN = -9.19 + 0.72 pKaMeCN.The equation for the previously investigated pyridine N-oxides has the following form: log k1MeCN = -5.63 + 0.70 pKaMeCN.Comparison of the parameters of the correlations shows that the pyridine N-oxides are ca. 1E4 times more reactive than the pyridines and imidazoles of equal basicity in acetonitrile.Possible reasons for the supernucleophilicity of pyridine N-oxides are discussed.
- Savelova, V. A.,Solomoichenko, T. N.,Ved', T. V.,Sadovskii, Yu. S.,Simanenko, Yu. S.
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p. 558 - 568
(2007/10/02)
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- Dependence of Transition-state Structure on Nucleophile in the Reaction of Aryl Oxide Anions with Aryl Diphenylphosphate Esters
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Second-order rate constants have been measured for reaction of aryl oxide anions with substituted phenyl diphenylphosphate esters in aqueous media at 25 deg C.The rate constants obey good Broensted type correlations with the pKa of either the leaving group or nucleophile.Both βnuc and βlg values vary substantially with basicity of leaving group and nucleophile, respectively, providing evidence for coupling between bond fission and formation.Attack of phenolate ions on 2,4-dinitrophenyl diphenylphosphate has a βnuc value of 0.12 giving a Kreevoy's tightness parameter value, τ, of 0.18 which is consistent with an 'exploded' transition state for the identity reaction involving 2,4-dinitrophenolate ion as the nucleophile.Transfer of the diphenylphosphinoyl group between 2,4-dinitrophenolate ion nucleophiles has a τ value of 0.28, consistent with an 'exploded' transition state for this reaction also.The identity reaction involving transfer of the diphenylphosphoryl group between phenolates ions has a τ value of 1.20, indicating an almost synchronous process.The data for transfer of the diphenylphosphinoyl and diethylphosphoryl groups between phenolate ion nucleophiles indicates that the identity reaction for the parent phenol has an almost synchronous mechanism for the former phosphinoyl species (τ = 0.92) whereas the latter (τ = 1.45) is almost associative.
- Ba-Saif, Salem A.,Waring, Mark A.,Williams, Andrew
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p. 1653 - 1659
(2007/10/02)
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- Metallomicelles as Catalysts of the Hydrolysis of Carboxylic and Phosphoric Acid Esters
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Lipophilic ligands 2-4 have been synthesized.In the presence of Cu(II) ions, they form metallomicelles that are catalytically active in the cleavage of the p-nitrophenyl esters of acetic, hexanoic, and dodecanoic acids.Catalysis was also observed in the cleavage of p-nitrophenyl diphenyl phosphate.The apparent pKa of the Cu(II)-coordinated hydroxyl of ligand 2a, in the micellar aggregate, is 7.7, as estimated from the rate vs pH profiles for both classes of esters: this suggests that the hydroxyl is involved as a nucleophile in the hydrolytic cleavage, which proved to be a really catalytic process.The ligand bearing the free hydroxyl (2a) is more effective in the cleavage of carboxylate esters than ligands with the methylated alcoholic group (2b) or devoid of it (4); the opposite behaviour is observed in the cleavage of the phosphate triester.A rationale is offered that calls for the difference in the coordination ability to the metal center of phosphate and carboxylate esters.
- Scrimin, Paolo,Tecilla, Paolo,Tonellato, Umberto
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p. 161 - 166
(2007/10/02)
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- Process for carbapenem intermediates
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A novel intermediate for synthesizing 1 β-alkyl-1-carbapenem, i.e., 4 β-(1 β-alkyl-2-carboxyprop-2-enyl)azetidin-2-one (II), is prepared stereoselectively by treating 4-(leaving group substituted)azetidin-2-one (I) with trans-2-(leaving group substituted)-methyl-3-alkylacrylic acid (III) and a reducing metal. STR1 wherein R1 is hydrogen, alkyl, or substituted alkyl; R2 is optionally substituted alkyl; R3 is hydrogen or a carboxy-protecting group; and R4 and R5 each is a leaving group.
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- Single transition state in the transfer of a neutral phosphoryl group between phenoxide ion nucleophiles in aqueous solution
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The second-order rate constants (kAro) for reaction of substituted phenoxide ions with 4-nitrophenyl diphenyl phosphate obey a linear equation over a range of 18 substituents with pKArOH values spanning the pKa of the leaving 4-nitrophenolate ion: log kArO =0.53pKArOH -6.6. The linear plot is consistent with a mechanism involving a single transition state or a two-step process with a very reactive intermediate with two almost identical transition states for its formation and breakdown; the value of the exponent (0.53) is also not consistent with a regular stepwise process with a discrete intermediate. The symmetrical reaction of 4-nitrophenolate ion with the 4-nitrophenyl ester is slightly imbalanced whereby bond formation does not keep up with bond fission in the transition state; the transition state, therefore, has some phosphorylium ion character. Transfer of the dielhylphosphoryl group between weakly basic oxyanion nucleophiles is probably a concerted process with a transition state with more of the character of the pentacoordinate intermediate than it has in the corresponding diphenylphosphoryl group transfer.
- Ba-Saif, Salem A.,Waring, Mark A.,Williams, Andrew
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p. 8115 - 8120
(2007/10/02)
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- Phosphate Esters in Organic Synthesis: The Alkylation of Aniline and N-Methylaniline by Allylic Diphenyl Phosphates.
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Allylic diphenyl phosphates react with aniline and N-methylaniline to give N-alkylation products.The reaction simulates the role played by pyrophosphate esters in the formation of nitrogen heterocycles in nature, while establishing that allylic phosphate esters can function as efficient alkylating agents in chemical systems.The procedure offers potential for a simple synthesis of quinoline derivatives.
- Onyiriuka, Samuel O.
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p. 2077 - 2085
(2007/10/02)
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- THIONO COMPOUNDS. 10. STRUCTURES AND REACTIONS OF INTERMEDIAATES FROM THE OXIDATION OF PHOSPHOROTHIOATES
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Intermediates from the oxidation of phosphorothioates, (RO)3PS, were studied previously at low temperature using 31P NMR, UV and Raman spectra.Now reported is further information about the structure of intermediates and about their reactions, both of which afford significant clues as to how phosphorothioates may produce adverse biological reactions after they have ben oxidized biologically.Mass spectra identified intermediates corresponding to (RO)3PSn with n up to 7 (although presence of some equivalent masses with two oxygens in place of a sulfur atom is possible).HPLC separated unstable intermediates for which UV and MS evidence again was consistent with the structure (RO)3PSn.That intermediates can react as nucleophiles is illustrated by reactions with Ellman's Reagent, which produced a maximum of thiolate ion at about the time 31P NMR and UV indicated a maximum of intermediates.A second illustration of nucleophilicity was reaction with N-ethylmaleimide (and other Michael acceptors), which led to thiiranes and thiirane 1-oxides.That the intermediates can react also as electrophiles is illustrated by reactions (followed by UV and 31P NMR) with trimethyl phosphite, hydroxyl ion, and water (perhaps to some extent); use of H2(18)O did not introduce (18)O into phosphate products, but exchange reactions with H2(18)O did indicate presence of oxygenated species among the intermadiates.Keywords: Ellman's Reagent; N-ethylmaleimide; 31P NMR spectra; Phosphorothioates; Thiiranes; UV spectra.
- Swinson, Joel,Field, Lamar,Heimer, Norman E.,Stone, Michael P.,Wazer, John R. Van
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- p-Methoxyphenacyl Esters as Photodeblockable Protecting Groups for Phosphates
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p-Methoxyphenacyl esters of substituted phosphates have been found to be photosensitive protecting groups which may be useful in biologically important phosphate synthesis.
- Epstein, William W.,Garrossian, Massoud
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p. 532 - 533
(2007/10/02)
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- HYDROLYSE BASIQUE COMPAREE D'ESTERS ALLOPHANIQUES ET PHOSPHORIQUES EN MILIEU MIXTE ACETONITRILE/EAU FAIBLEMENT AQUEUX; MISE EN EVIDENCE D'UNE ENTITE CATALIQUE, INTERMEDIARE DE LA REACTION ENTRE BASE ET SOLVANT
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Kinetic study of base catalysed hydrolysis in acetonitrile-water mixtures of allophanic esters (models of carboxybiotine) and phosphoric esters shows in the range of low water content (less than 1 molar) an enhancement in rate (103) with a maximum at 0.1-0.3 molar in water.This rate enhancement is ascribed to ground state desolvation and the maximum is interpreted by a change in the rate determining step: leaving group departure in the tetrahedral intermediate is indeed the slow step for the reactions in acetonitrile/water mixture less than 0.1 molar in water.For charged phosphoric esters the rate enhancement from an aqueous medium (pH=10) to organic is larger since as high as 106.On the other hand, in such a medium, an additional catalytic effect is observed; it is shown that it is due to the formation of a reactive species which results from reaction of the base on acetamide when accumulated in the medium from base catalysed hydrolysis of the solvent.
- Monnier, Par E.,Botella, J. M.,Murillo, A.,Klaebe, A.,Perie, J.
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p. 1315 - 1332
(2007/10/02)
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- REACTION OF SUGAR EPOXIDES WITH PHOSPHOROTHIOIC ACIDS, EVIDENCE OF THE PENTACOORDINATE PHOSPHORUS INTERMEDIATE IN THE REACTION OF 5,6-ANHYDRO-1,2-O-ISOPROPYLIDENE-α-D-GLUCOFURANOSE WITH PHOSPHOROTHIOIC ACIDS
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The reaction of sugar epoxides with organic monothioacids of phosphorus provides a convenient procedure for synthesizing sugar thiophosphates and mercaptosugar phosphates.Based on detailed analysis of intermediates and factors influencing the reactivity of phosphorus monothioacids with sugar epoxides the reaction scheme is proposed involving pentacoordinate intermediate which undergoes endo or/and exocyclic elimination.It was found that the reaction of 5,6-anhydro-1,2-O-isopropylidene-α-D-glucoforanose 7 with phosphorothioic acids 8a and 8b yields three types of products in equilibrium: the thiophosphates 9a and 9b, the oxathiaphospholanes 11a and 11b and the mercaptophosphates 10a and 10b.Under more drastic conditions the phosphates 10a and 10b can be converted irreversibly into the episulphide 12 and phosphoric acids 13a and 13b, respectively.It is clearly possible that both compounds 10 and 11 can be formed from the same pentacoordinate intermediate, and the experimental evidence provides strong support for it.
- Kudelska, Wieslawa,Michalska, Maria
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p. 629 - 636
(2007/10/02)
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- Catalytic Hydrolysis of a Phosphate Triester by Tetracoordinated Zinc Complexes
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A zinc complex of a tetraaza macrocycle catalyzes the hydrolysis of diphenyl p-nitrophenyl phosphate in aqueous acetonitrile.The principial products derive from loss of p-nitrophenol, but some alternative hydrolysis with loss of phenol is also observed.Ki
- Gellman, Samuel H.,Petter, Russell,Breslow, Ronald
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p. 2388 - 2394
(2007/10/02)
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