- New acyloxy nitroso compounds with improved water solubility and nitroxyl (HNO) release kinetics and inhibitors of platelet aggregation
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New acyloxy nitroso compounds, 4-nitrosotetrahydro-2H-pyran-4-yl 2,2,2-trichloroacetate and 4-nitrosotetrahydro-2H-pyran-4-yl 2,2-dichloropropanoate were prepared. These compounds release HNO under neutral conditions with half-lives between 50 and 120 min, identifying these HNO donors as kinetically intermediate to the much slower acetate derivative and the faster trifluoroacetic acid derivative. These compounds or HNO-derived from these compounds react with thiols, including glutathione, thiol-containing enzymes and heme-containing proteins in a similar fashion to other acyloxy nitroso compounds. HNO released from these acyloxy nitroso compounds inhibits activated platelet aggregation. These acyloxy nitroso compounds augment the range of release for this group of HNO donors and should be valuable tools in the further study of HNO biology.
- Mohamed, Heba A.H.,Abdel-Aziz, Mohamed,Abuo-Rahma, Gamal El-Din A.A.,King, S. Bruce
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p. 6069 - 6077
(2015/11/10)
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- Promotive effects in α-monochloropropionic acid catalytic synthesis with propionic anhydride
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Selective α-chlorination of propionic acid to synthesize α-monochloropropionic acid was investigated in a laboratory-scale at 130 °C at atmospheric total pressure and in the presence of propionic anhydride as catalyst. Sulfuric acid and common Lewis acid were selected as promotive catalysts considering that the acid-catalyzed enolization is the rate determining step in the chlorination reaction of this experiment, also the reaction selectivity and activity were discussed in the presence of promotive catalysts. The studies revealed that the ferric chloride and sulfuric acid all have prominent promotive effects. Typically the amount of α- monochloropropionic acid can reach 96.14 % when 0.07 g of ferric chloride was added. Furthermore, our results demonstrated that the reaction selectivity and activity were dramatically enhanced after introducing Lewis acid as promotive catalysts.
- Xue, Jianwei,Qi, Beibei,Wen, Xiaoguang,Wang, Yingying,Lv, Zhiping,Li, Fuxiang
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p. 481 - 485
(2014/06/09)
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- Oxidation of aliphatic 2,2-dichloroalkanals by HNO3 in CH 2Cl2: An easy and eco-friendly route to the corresponding 2,2-dichloroalkanoic acids
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A simple, economically convenient, and eco-compatible procedure for the oxidation of 2,2-dichloroalkanals to the corresponding alkanoic acids has been set up, employing HNO3 in CH2O2, in the presence of NaNO2 as catalyst.
- Bellesia, Franco,De Buyck, Laurent,Ghelfi, Franco,Pagnoni, Ugo M.,Strazzolini, Paolo
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p. 1473 - 1481
(2007/10/03)
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- pH-independent hydrolysis of 4-nitrophenyl 2,2-dichloropropionate in aqueous micellar solutions: Relative contributions of hydrophobic and electrostatic interactions
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The pH-independent hydrolysis of 4-nitrophenyl 2,2-dichloropropionate (NPDCP) in the presence of aqueous micelles of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, alkyltrimethylammonium chlorides, alkyldimethylbenzylammonium chlorides (alkyl = cetyl and dodecyl) and polyoxyethylene(9) nonylphenyl ether was studied spectrophotometrically. The observed rate constants, kobs, decrease in the following order: bulk water >cationic micelles >anionic micelles >non-ionic micelles. This order is different from that observed for pH-independent hydrolysis of 4-nitrophenyl chloroformate (NPCF), whose reaction is faster in cationic micelles than in bulk water. A proton NMR study on solubilization of a model ester, 4-nitrophenyl 2-chloropropionate, showed that the methylene groups in the middle of the surfactant hydrophobic chain are most affected by the solubilizate. Lower polarity and high ionic strength of interfacial water decrease the rates of hydrolysis of both NPCF and NPDCP, but t he fraction of the former ester that diffuses to the interface is probably higher than that of the latter. Therefore, whereas the (negatively charged) transition state of NPCF is stabilized by cationic interfaces and destabilized by anionic interfaces, that of NPDCP is negligibly affected by ionic interfaces, which explains the observed rate retardation by all ionic micelles. Calculated activation parameters corroborate our explanation.
- Seoud, Omar A. E.I.,Ruasse, Marie-Francoise,Possidonio, Shirley
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p. 526 - 532
(2007/10/03)
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- 2,2-dichloroaldehydes and 2,2-dichlorocarboxylic acids from 2- picoline·HCl catalyzed chlorination of aldehydes
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An efficient preparation of 2,2-dichloroaldehydes and 2,2- dichlorocarboxylic acids has been achieved by chlorination of aldehydes using 2-picoline hydrochloride as recoverable catalyst.
- Bellesia, Franco,De Buyck, Laurent,Ghelfi, Franco
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p. 146 - 148
(2007/10/03)
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- Halogen atom transfer radical cyclization of N-allyl-N-benzyl-2,2-dihaloamides to 2-pyrrolidinones, promoted by Fe0-FeCl3 or CuCl-TMEDA
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The halogen atom transfer radical cyclization of a N-allyl-N-benzyl-2,2-dihaloamides to 2-pyrrolidinones has been carried out in high yields under mild conditions, in a reaction promoted by CuCl-TMEDA or Fe0-FeCl3 in acetonitrile or N,N-dimethylformamide, respectively.
- Benedetti, Miriam,Forti, Luca,Ghelfi, Franco,Pagnoni, Ugo Maria,Ronzoni, Roberto
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p. 14031 - 14042
(2007/10/03)
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- Kinetics and mechanism of the hydrolysis of 1-aryloxyethyl alkanoates
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The kinetics and mechanism of the hydrolysis of 1-aryloxyethyl alkanoates are reported.In acidic media, 18O isotope exchange studies, kinetics, activation parameters and substituent effects point clearly to an AAl-1 mechanism with the formation of an alkoxycarbonium ion as the rate-limiting step.In basic media the data indicate a conventional BAc-2 mechanism through attack of hydroxide ion on the carbonyl carbon.In neutral medium (pH 2.5-8.8) there is a certain amount of conflicting evidence which leads, however, to the proposal that hydrolysis occurs via attack of a water molecule on the acyl carbon as the rate-limiting step.
- Hall, C. Dennis,Goulding, Celia W.
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p. 1471 - 1478
(2007/10/02)
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- Method of manufacturing a dry water-soluble herbicidal salt composition
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A method of manufacturing a solid, water-soluble herbicidal composition comprising a water-soluble salt of a herbicidal compound is disclosed. The herbicidal compound is a water-insoluble compound that includes a carboxylic acid functionality, such as a phenoxy-substituted carboxylic acid compound or a substituted benzoic acid compound, and is sufficiently pure to form a dry, solid herbicidal salt composition after interaction with a suitable neutralizing base, such as ammonia, an alkylamine, a dialkylamine, a trialkylamine, a hydroxyalkylamine, a dihydroxyalkylamine, an alkaline salt of an alkali metal or a combination thereof. The dry herbicidal salt composition includes at least about 90% by weight of the water-soluble herbicidal salt, and dissolves rapidly and essentially completely in water to form an aqueous herbicidal solution including up to about 75% by weight of the water-soluble herbicidal salt.
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- Pyridylthio-acylanilide herbicides
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Novel herbicidally active pyridylthio-acylanilides of the formula STR1 in which R1, R2 and R3, independently of one another, represent hydrogen, halogen, cyano or trifluoromethyl or alkyl, alkoxy and alkylthio having 1 to 4 carbon atoms in each case, R4 represents halogen, methyl or methoxy, n represents a number 0, 1 or 2, z represents the group (Ia) STR2 or the group (Ib) STR3 where X represents oxygen, sulphur, an N--R10 or N--O--R11 group, or X and Rg tpgether represent the STR4 radical, and the other radicals can have various meanings. Intermediates of the formulae STR5 are also new.
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- FREE-RADICAL REACTIONS OF 1,1,2-TRICHLOROPROPENE. I. PHOTOOLIGOMERIZATION OF 1,1,2,-TRICHLOROPROPENE
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The UV irradiation of 1,1,2-trichloropropene leads to the production of a complex mixture of products with the molecular formulas C6H5Cl5, C6H4Cl6, C6H5Cl7 and also CH3CCl2COOH and CH3CCl2COCl.By chromatomass spectrometry and IR and PMR spectroscopy it was shown that in addition to the acid and the acid chloride the main products are 1,1,2,4,5,6-hexachloro-1,4-hexadiene CCl2=CClCH2CCl=CClCH2Cl and 1,1,2,4,4,5,5-heptachloro-1-hexene CCl2=CClCH2CCl2CCl2CH3.
- Martynov, A.V.,Mirskova, A. N.,Vitkovskii, V. Yu.,Voronkov, M. G.
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p. 631 - 634
(2007/10/02)
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- FREE-RADICAL REACTIONS OF 1,1,2-TRICHLOROPROPENE. III. FREE-RADICAL THIYLATION OF TRICHLOROPROPENE BY DIARYL DISULFIDES
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The reaction of CCl2=CClCH3 with ArSSAr (Ar = 4-ClC6H4, C6H5, 4-CH3C6H4), initiated by UV irradiation, in a quartz flask leads to the formation of a mixture of isomeric sulfides ArSC(CH3)=CCl2 and cis- and trans-ArSCCl=CClCH3 and also the sulfides ArSCH2CCl=CCl2 and ArSCCl2CCl2CH3.In addition, significant amounts of the products from oxidation and oligomerization of trichloropropene CH3CCl2COOH, CCl2=CClCH2CCl=CClCH2Cl, and CCl2=CClCH2CCl2CCl2CH3 are formed.The oligomerization of trichloropropene is almost completely suppressed in molybdenum glass.A reaction mechanism involving the formation of the radicals ArSC(CH3)ClC.Cl2 and ArSCCl2C.ClCH3 and the allyl radical .CH2CCl=CCl2 is proposed.
- Martynov, A. V.,Mirskova, A. N.,Vitkovskii, V. Yu.,Voronkov, M. G.
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p. 1061 - 1065
(2007/10/02)
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- Inhibition of Water-Catalyzed Ester Hydrilysis in Hydrophobic Microdomains of Poly(methacrylic acid) Hypercoils
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The water-catalyzed hydrolysis of p-methoxyphenyl dichloroacetate (1) and 2,2-dichloropropionate (2) in aqueous solution at 25 deg C is strongly retarded by neutral atactic (at) and syndiotactic (st) poly(methacrylic acid) (PMAA), but not by poly(acrylic acid) and poly(N-vinylpyrrolidone).The rates and thermodynamic activation parameters are consistent with binding of the substrates to hydrophobic microdomains within the PMAA hypercoil.A conformational transition of PMAA to an extended coil leads to disappearance of the rate inhibition.This transition is induced either by ionization of PMAA or, at constant pH (ca. 3), by addition of urea and can be monitored by potentiometric titrations.Solubility measurements employing the water-insoluble dye Orange OT further established hydrophobic bonding to neutral at-PMAA.Whereas inhibition of the hydrolysis of 1 and 2 in water in the presence of hydrophobic cosolvents or micelles is characterized by initial-state stabilization, it appears that the inhibition by at- and st-PMAA primarily involves destabilization of the transition state.The effect of PMAA may be explained in terms of a lack of water penetration into the hydrophobic microdomains.
- Jager, Jan,Engberts, Jan B. F. N.
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p. 3331 - 3334
(2007/10/02)
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- Heat Capacities of Activation for the Neutral Hydrolysis of Two Acyl-Activated Esters in Water-Rich 2-n-Butoxyethanol-Water Mixtures. Analysis in Terms of the Pseudo-Phase-Separation Model
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The water-catalyzed hydrolysis of p-methoxyphenyl dichloroacetate (1) and 2,2-dichloropropionate (2) in water-rich 2-n-butoxyethanol (2-BE)-H2O exhibits large, positive heat capacities of activation (1, ΔCp = 224 +/- 51 cal mol-1 deg-1; 2, ΔCp = 342 +/- 51 cal mol-1 deg-1; temperature 20-48 deg C) at 2 mol percent of 2-BE (nH2O = 0.98).These positive ΔCp values contrast sharply with the negative ΔCp's found for SN solvolysis reactions in highly aqueous mixed solvents.By use of a pseudothermodynamic approach, the ΔCp values as well as positive heat capacities for transfer (ΔCpΘ,tr) of two model substrates from water to 2-BE-H2O are rationalized within the framework of a pseudo-phase-separation model.Based on previous thermodynamic and other evidence, this model assumes the onset of microphase separation in 2-BE-H2O at about nH2O = 0.98 at 25 deg C.It is shown that temperature-dependent partitioning of the acyl-activated esters between a water-rich and a cosolvent-rich microphase provides an adequate explanation for the observed heat capacity data.The observed ΔCp for solvolysis of tert-butyl chloride in 2-BE-H2O at nH2O = 0.98 is also reconcilable with the proposed theory.
- Holterman, Herman A. J.,Engberts, Jan B. F. N.
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p. 4025 - 4030
(2007/10/02)
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- Isobaric and Isochoric Activation Parameters for the Water-Catalyzed Hydrolysis of p-Methoxyphenyl 2,2-Dichloropropionate in Typically Aqueous Solutions
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Isobaric thermodynamic activation parameters (ΔGp, ΔHp, ΔSp) and volumes of activation (ΔV) have been measured for the water-catalyzed hydrolysis of p-methoxyphenyl 2,2-dichloropropionate (1) in water and in t-BuOH-H2O (nH2O = 0.950 and 0.925) and 2-n-butoxyethanol-H2O (nH2O = 0.980) at 25 deg C.These data, in combination with the isobaric thermal expansivities (α) and the isothermal compressibilities (β) of the solvent, were used to calculate the isochoric activation parameters ΔUv and ΔSv.It is found that the solvent dependence of the sets (ΔHp, ΔSp) and (ΔUv, ΔSv) is widely different as a result of the large changes in α/β and in ΔV.The results are interpreted mainly in terms of hydrophobic interactions between 1 and the organic cosolvent and the large electrostriction, as expressed in the strongly negative ΔV values.The analysis is facilitated by consideration of thermodynamic parameters for transfer of a model substrate (p-nitrophenyl propionate) from water to the t-BuOH-H2O system.It is concluded that both isobaric and isochoric activation parameters contain fundamental information about the solvation changes during the activation process.There is no compelling evidence to prefer either of these sets for an analysis of kinetic solvent effects on the hydrolysis of 1 in the solvent systems used.
- Holterman, Herman A. J.,Engberts, Jan B. F. N.
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p. 6382 - 6384
(2007/10/02)
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- Novel acyloxamides and plant growth regulant compositions
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Acyloxamide compounds of the formula STR1 in which R is chlorine, alkyl of from 1 or 2 carbon atoms or chloroalkyl of from 1 or 2 carbon atoms and 1 to 5 chlorine atoms e.g., 2,2-dichloropropionyl-oxamide and trichloroacetyl-oxamide are outstandingly effective as plant growth regulants. sp This is a continuation of application Ser. No. 964,223 filed Nov. 27, 1978, abandoned.
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- Pesticide-polymer systems prepared from vinyl monomers
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Controlled release pesticide-polymer systems are prepared by the polymerization of vinyl monomers containing pendant pesticides. The vinyl monomers are prepared by reacting an acrylic acid derivative with a pesticide or a pesticide derivative having an active hydrogen. The pesticide-polymer systems prepared from the pesticide vinyl monomers release the active pesticide material by hydrolysis or chemical depolymerization under conditions of use.
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- 1,2-Dimethyl-3,5-diphenylpyrazolium-2,2-dichloropropionate
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The invention is novel compositions containing a pyrazolium salt and a polyhalocarboxylic acid, an alkali metal or alkaline earth metal polyhalocarboxylate salt useful in the control of wild oats and other undesirable grass plants. The invention includes a herbicidal salt of the pyrazolium cation and the polyhalocarboxylate anion.
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- Certain ethers of certain di and trihalo-1-hydroxy-2-(fluoroalkyl)1H-imidazo(4,5-b)pyridine derivatives
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Ethers of di and trihalo-1-hydroxy-2-(1,1-difluoroalkyl)-1H-imidazo(4,5-b)pyridine compounds, useful as herbicides and rodenticides.
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- Esters of 1-hydroxy-1H-imidazo-(4,5-b)-pyridines as herbicides
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Ethers and esters of 1-hydroxy-2-(1,1-difluoroalkyl)-1H-imidazo(4,5-b)pyridine compounds, useful as herbicides.
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- 1H-imidazo(4,5,-b)-pyridine derivatives
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Ethers and esters of 1-hydroxy-2-(1,1-difluoroalkyl)-1H-imidazo(4,5-b)pyridine compounds, useful as herbicides.
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