- Preparation and properties of two novel selenoacetic acids: HCF 2C(O)SeH and ClCF2C(O)SeH
-
The novel selenocarboxylic Se-acids, HCF2C(O)SeH and ClCF 2C(O)SeH, were prepared by treating the corresponding carboxylic acids with Woollins' reagent. The boiling points were extrapolated from the vapor pressure curves to be 364 and 359 K for HCF2C(O)SeH and ClCF2C(O)SeH, respectively. Both compounds are unstable at ambient temperatures and decompose to the corresponding seleno anhydrides and release of H2Se. Hydrolysis results in formation of the carboxylic acids and hydrogen selenide, while diselenides presumably are obtained by oxidation. The conformational properties of these acids were studied by vibrational spectroscopy in combination with ab initio and DFT methods. IR vapor-phase spectra, Raman spectra of the neat liquids, and IR spectra of the Ar-matrix-isolated compounds deposited at two different nozzle temperatures were interpreted in terms of quenching conformational equilibria. The most stable structure of both acids was found to be syn-gauche in equilibrium with a second anti-syn form in HCF2C(O)SeH and with another two conformers, anti-gauche and anti-syn, in ClCF2C(O)SeH.
- Gomez Castano, Jovanny A.,Romano, Rosana M.,Beckers, Helmut,Willner, Helge,Della Vedova, Carlos O.
-
-
Read Online
- Decarbonylative Fluoroalkylation at Palladium(II): From Fundamental Organometallic Studies to Catalysis
-
This Article describes the development of a decarbonylative Pd-catalyzed aryl-fluoroalkyl bond-forming reaction that couples fluoroalkylcarboxylic acid-derived electrophiles [RFC(O)X] with aryl organometallics (Ar-M′). This reaction was optimized by interrogating the individual steps of the catalytic cycle (oxidative addition, carbonyl de-insertion, transmetalation, and reductive elimination) to identify a compatible pair of coupling partners and an appropriate Pd catalyst. These stoichiometric organometallic studies revealed several critical elements for reaction design. First, uncatalyzed background reactions between RFC(O)X and Ar-M′ can be avoided by using M′ = boronate ester. Second, carbonyl de-insertion and Ar-RF reductive elimination are the two slowest steps of the catalytic cycle when RF = CF3. Both steps are dramatically accelerated upon changing to RF = CHF2. Computational studies reveal that a favorable F2C-H - -X interaction contributes to accelerating carbonyl de-insertion in this system. Finally, transmetalation is slow with X = difluoroacetate but fast with X = F. Ultimately, these studies enabled the development of an (SPhos)Pd-catalyzed decarbonylative difluoromethylation of aryl neopentylglycol boronate esters with difluoroacetyl fluoride.
- Lalloo, Naish,Malapit, Christian A.,Taimoory, S. Maryamdokht,Brigham, Conor E.,Sanford, Melanie S.
-
supporting information
p. 18617 - 18625
(2021/11/16)
-
- Synthesis process of difluoroacetic acid
-
The synthesis process comprises the following steps: adding dialkylamines in a dry reaction vessel, first organic solvent and volume concentration of 10 - 40% alkali liquor, dropwise adding dichloroacetyl chloride, carrying out heat preservation stirring after dropwise addition, organic subtraction pressure desolventizing and concentrating to obtain dichloroacetyl dialkylamine. Potassium fluoride, second organic solvent and dichloroacetyl dialkylamine were added to another reaction vessel, and the molar ratio @timetime@ and thermal insulation of the potassium fluoride, the solvent diethylene glycol and the dichloroacetyl 3:5:1 dialkylamine is @. The equimolar difluoroacetyl dialkylamine and the volume concentration were mixed with 10 - 30% lye, reflux was 4 - 10h, dichloroacetyl dialkylamine was recovered by distillation, and the bottoms of the bottoms were adjusted pH=1 with hydrochloric acid and distilled again to give difluoro acetic acid.
- -
-
Paragraph 0022; 0024-0025; 0027-0028; 0030-0031; 0033; ...
(2021/11/14)
-
- Synthetic method of difluoroacetic acid
-
The invention relates to a synthetic method of difluoroacetic acid, belonging to the technical field of organic fluorine chemical industry. According to the synthetic method of difluoroacetic acid, 1,1-difluoroethane (R152a) and hydrogen peroxide are taken as raw materials, difluoroacetic acid is prepared in one step, unreacted 1,1-difluoroethane (R152a) is recycled after recovery, the selectivityand conversion rate of the target product are high, and the synthetic method is non-corrosive to equipment, safe and environment-friendly. A catalyst used in the invention is a solid acid catalyst, has high catalytic efficiency, can be repeatedly used, can be easily separated from a reaction system after the reaction is finished, and is particularly suitable for preparing difluoroacetic acid from1,1-difluoroethane (R152a) and hydrogen peroxide. Raw materials adopted in the invention are common reagents and easily available and cheap; and reaction conditions are mild, and a reaction process is easy to control. The prepared difluoroacetic acid product has higher yield and is suitable for industrial production.
- -
-
Paragraph 0021-0039
(2021/03/24)
-
- Preparation method of difluoroacetic acid
-
The invention relates to a preparation method of difluoroacetic acid, and belongs to the technical field of fluorine chemical engineering. According to the preparation method of the difluoroacetic acid, KMnO4/C solid catalysts are added into a fixed bed reaction kettle; nitrogen gas is introduced to perform replacement on the air in the reaction kettle; the temperature is raised to a fixed temperature; then, hydrogen peroxide and 2-chlorine-1,1-difluoroethane are introduced by a voltage stabilizing pump to perform contact reaction; after a product is separated, the product of difluoroacetic acid is finally obtained. The preparation method of the difluoroacetic acid has the advantages that the process is simple; the flow process is short; the technical flow process is simplified; the energyconsumption is greatly reduced; the method is suitable for industrialized production; the used raw materials are all common reagents, the resources of the materials are wide, and the price is low; the reaction process can be easily controlled; the obtained difluoroacetic acid product has high yield and has wide application and popularization values.
- -
-
Paragraph 0020-0025
(2019/04/10)
-
- Practical Processes for Producing Fluorinated alpha-Ketocarboxylic Esters and Analogues Thereof
-
It is possible to produce a fluorine-containing α-ketocarboxylic ester hydrate by reacting a fluorine-containing α-hydroxycarboxylic ester with sodium hypochlorite or calcium hypochlorite of 21 mass % or greater in mass percentage of composition. Furthermore, it is possible to produce a fluorine-containing α-ketocarboxylic ester by reacting the hydrate with a dehydrating agent. Furthermore, it is possible to produce a fluorine-containing α-ketocarboxylic ester hemiketal by reacting the fluorine-containing α-ketocarboxylic ester hydrate with a lower alcohol or a trialkyl orthocarboxylate. Moreover, it is possible to produce a fluorine-containing α-ketocarboxylic ester by reacting the hemiketal with a dealcoholization agent.
- -
-
Paragraph 0184; 0185; 0186
(2018/03/10)
-
- Process for the Preparation of Difluroacetic Acid
-
A process is provided for the preparation of difluoroacetic acid from tetrafluoroethylene. The process comprises reacting tetrafluoroethylene with an aqueous solution of an inorganic base, optionally in the presence of an organic solvent.
- -
-
Paragraph 0032; 0033
(2013/09/12)
-
- PROCESS FOR PREPARING DIFLUOROACETIC ACID, SALTS THEREOF OR ESTERS THEREOF
-
A process for preparing difluoroacetic acid, salts thereof or esters thereof is described. The process can further include preparation of difluoroacetic acid, salts thereof or esters thereof, wherein the reaction occurs in the presence of water of a salt providing a fluoride anion and of monohalogenated or dihalogenated acetic acid, in acid, salified or esterified form, at least one halogen atom being other than the fluorine atom.
- -
-
Paragraph 0106; 0107; 0108; 0109; 0110
(2013/06/04)
-
- METHOD FOR PREPARING DIFLUOROACETIC ACID
-
A method for preparing difluoroacetic acid is described. The method can include: reacting a difluoroacetic acid ester with an aliphatic carboxylic acid which, after transesterification, results in the formation of difluoroacetic acid and the corresponding carboxylic acid ester, the carboxylic acid being selected such that the ester of the carboxylic acid has a lower boiling point than that of difluoroacetic acid; and removing the ester of the carboxylic acid by distillation as the ester forms, thus enabling the difluoroacetic acid to be recovered.
- -
-
Page/Page column 3-4
(2012/05/21)
-
- PROCESS FOR THE PREPARATION OF DIFLUOROACETIC ACID
-
A process is provided for the preparation of difluoroacetic acid from tetrafluoroethylene. The process comprises reacting tetrafluoroethylene with an aqueous solution of an inorganic base, optionally in the presence of an organic solvent.
- -
-
Page/Page column 5-6
(2012/05/31)
-
- METHOD FOR SEPARATING A CARBOXYLIC ACID IN SALIFIED FORM BEARING AT LEAST ONE HALOGEN ATOM
-
The subject of the present invention is a method for separating a carboxylic acid in salified form bearing at least one halogen atom at the α position of the carbonyl group from a medium comprising it. The method according to the invention, for separating a carboxylic acid in salified form bearing at least one halogen atom at the α position of the carbonyl group from an aqueous medium comprising it, is characterized by the fact that the latter is brought into contact with an onium salt leading to the formation of two phases: an organic phase comprising the salt resulting from the reaction of the salt of the carboxylic acid bearing at least one halogen atom at the α position of the carbonyl group and of the onium salt leading to the displacement of the cation from the carboxylic acid by the onium, an aqueous phase comprising the various salts, in particular the one resulting from the reaction of the cation of the carboxylic acid with the anion of the onium, and by the fact that the organic and aqueous phases are then separated and that the onium salt of the carboxylic acid is recovered from the organic phase.
- -
-
Page/Page column 5
(2011/07/29)
-
- Heterocyclic-substituted alkanamides as therapeutic compounds
-
Use of compounds of the general formula (I) and pharmaceutically acceptable salt thereof, in which R1 and R2 have the definitions illustrated in detail in the description, as beta-secretase, cathepsin D, plasmepsin II and/or HIV protease inhibitors.
- -
-
-
- 5-AMINO-4-HYDROXY-7- (IMIDAZO [1,2-A] PYRIDIN-6- YLMETHYL)-8-METHYL-NONAMIDE DERIVATIVES AND RELATED COMPOUNDS AS RENIN INHIBITORS FOR THE TREATMENT OF HYPERTENSION
-
Compounds of the general formula (I) or its salt or a compound in which one or more atoms are replaced by their stable, nonradio-active isotopes, in particular its pharmaceutically acceptable salt; in which X is -CH2-; R1 is a mono- to tetrasubstituted, mono- or bicyclic, unsaturated heterocyclic radical having 1 to 4 nitrogen atoms, R2 is C1-6alkyl or C3-6cycloalkyl; R3 is independently of one another H, C1-6alkyl, C1-6alkoxycarbonyl or C1-6alkanoyl; R4 is C2-6alkenyl, C1-6alkyl, unsubstituted or substituted aryl- C1-6alkyl or C3-8cycloalkyl; R5 is -Lm-R6; L is C1-6alkylene which is optionally substituted by 1-4 halogen, or a linker: formula (II) n = 0, 1 or 2; m = 0 or 1; R6 is a radical composed of 2 cyclic systems selected from bicyclo[x.y.z]alkyl, spiro[o.p]alkyl, mono- or bioxabicyclo[x.y.z]alkyl or mono- or bioxaspiro[o.p]alkyl, all of which may be substituted by 1-3 substituents selected from C1-6alkyl, C1-6alkoxy, cyano, halogen, C1-6alkoxy- C1-6alkyl, hydroxy-C1-6alkyl or dialkylamino, or if m = 0: is also saturated C3-8heterocyclyl which comprises 1-2 oxygen atoms, substituted by 1-3 substituents selected from C1-6alkyl, C1-6alkoxy, cyano, halogen, C1-6alkoxy- C1-6alkyl, hydroxy- C1-6alkyl or dialkylamino, or if m = 1: is also saturated C3-8heterocyclyl which comprises 1-2 oxygen atoms, optionally substituted by 1-3 substituents selected from C1-6alkyl, C1-6alkoxy, cyano, halogen, C1-6-alkoxy-C1-6alkyl, hydroxy-C1-6alkyl or dialkylamino; have renin- inhibiting properties and can be used as medicines for the treatment of hypertension.
- -
-
Page/Page column 55
(2008/06/13)
-
- Preparation of compounds comprising a CHF2 or CHF group
-
Producing compounds (I) with a mono- or difluoromethyl group from compounds (II) with a mono- or difluorohalomethyl group, where halo is bromo, iodo or preferably chloro, comprises reacting (II) with zinc in the presence of an alcohol. An independent claim is also included for an azeotropic mixture of methyl difluoroacetate and methanol.
- -
-
Page/Page column 2; 3
(2008/06/13)
-
- Electrochemical fluorination of benzamide and acetanilide in anhydrous HF and in acetonitrile
-
Electrochemical fluorination of benzamide in anhydrous hydrogen fluoride does not involve the amide group but occurs exclusively at the aromatic ring, yielding isomeric fluoro- and difluorobenzamides and 3,3,6,6-tetrafluoro-1,4- cyclohexadienecarboxamide.
- Shainyan,Danilevich,Grigor'eva,Chuvashev
-
p. 513 - 517
(2007/10/03)
-
- Radical-mediated degradation mechanisms of tribromo- and other trihalogenated acetic acids in oxygen-free solutions as studied by radiation chemistry methods
-
.CBr2CO2- and .CCl2CO2- radicals, generated upon one electron reduction of tribromo- and trichloroacetic acids and .CF2CO2- radicals produced from difluoroacetic acid by reaction with .OH, exhibit optical absorptions in the UV with λmax at 290 nm (ε = 2580 dm3 mol-1 cim-1), 330 nm (ε = 3000 dm3 mol-1 cm-1) and 310 nm (ε ≈ 660 dm3 mol-1 cm-1), respectively. Mechanistically, the present report focuses on the free-radical-induced degradation of tribromoacetic acid. Absolute rate constants have been determined for the reactions of CBr3CO2- with eaq-, H., CO2. , .CH2OH, CH3.CHOH, (CH3)2.COH and .CH3 radicals to be k = 1.8 × 1010, 1.5 × 1010, 2.8 × 109, 1.6 × 109, 2.3 × 109, 3.0 × 109 and 3.0 × 107 dm3 mol-1 s-1, respectively. The major fate of .CBr2CO2- is self-termination to yield tetrabromosuccinic acid which, however, is unstable and thermally decomposes to HBr, CO2 and tribromoacrylic acid. Dibromofumaric acid, dibromomaleic acid and carbon monoxide were found as minor secondary products, formation of which is explained by a small yield of reductive decomposition of the transient tetrabromosuccinic acid. A complete and mechanistically satisfying material balance is provided for several systems in which CBr3CO2- has been degraded via a variety of radicals under various conditions. .OH Radicals do not react directly with CBr3CO2-. They have been shown, however, to contribute indirectly to the degradation of this acid via their reaction with reductively liberated bromide ions. The Br. atoms formed in this process are considered to abstract a bromine atom from CBr3CO2- or oxidize the carboxyl function in a one-electron transfer process. The formation of free Br. atoms has been recognized by pulse radiolysis through their conjugate dimer radical anions Br2.-. With respect to the other trihalogenated acids it is noteworthy that CCl3CO2- is efficiently reduced by CO2.- radicals and that CF3CO2- exhibits a high stability toward γ-irradiation and practically resists any reductive attack.
- Fliount, Roman,Makogon, Oksana,Guldi, Dirk M.,Asmus, Klaus-Dieter
-
p. 1535 - 1545
(2007/10/03)
-
- Surface Chemistry of Perfluoroether: A Study of the Reaction Mechanism of (C2F5)2O with an Al2O3 Surface by FTIR Spectroscopy
-
The decomposition of perfluorodiethyl ether on alumina has been studied at 300 and 500 K by transmission infrared spectroscopy using excess ether under high-pressure conditions.It was found in this study that the reaction products include trifluoro-, difluoro-, and monofluoroacetate, fluoroformate, alkyl acetate, and alkyl formate.The initial formation of trifluoroacetate probably results from a nucleophilic attack at the α-carbon of the ether by a surface oxygen anion.Subsequently, fluorine atoms, abstracted by coordinately unsaturated (cus) aluminum atoms, are replaced by hydrogen atoms donated by isolated surface hydroxyls.There is also evidence that fluoroalkene and fluoroalkyne resulted from the decomposition of initial surface adsorbates.
- Lyth, E.,Ng, L. M.
-
p. 17615 - 17623
(2007/10/03)
-
- Synthesis of 3,3-difluoro-DL-alanine and 3,3-difluoro-DL-alanine precursors
-
The key intermediate to 3,3-difluoroalanine, 2,2-difluoro-1-ethylthioethylamine hydrobromide (2), was prepared by the Steglich and Weygand procedure. Its conversion to N-benzyloxycarbonyl-2,2-difluoro-1-ethenylethylamine (5) followed by oxidation and subsequent deprotection of the amine afforded the 3,3-difluoroalanine.
- D'Orchymont
-
p. 961 - 963
(2007/10/02)
-
- Catalytic hydrogen-transfer reduction of polyhalofluoroalkanes using sodium hypophosphite
-
The catalytic hydrogen-transfer reduction of polyhalofluoroalkanes using sodium hypophosphite in the presence of a platinum or palladium catalyst is described.A selective reduction of carbon-bromine bonds could be performed under mild conditions.
- Hu, Chang-Ming,Tu, Ming-Hu
-
p. 101 - 104
(2007/10/02)
-
- Proton transfers among oxygen and nitrogen acids and bases in DMSO solution
-
Rate constants for the proton-transfer reactions between conjugate acids and bases of several amines, phenols, carboxylic acids, and the solvated proton in DMSO-d6 at 20 °C have been determined by the use of NMR line-shape analysis. Equilibrium constants for the same reactions are obtained from the pKa's of the acids in dimethyl sulfoxide, some of which have been reported in earlier work and the rest obtained in the present work by use of Bordwell's indicator techniques. All of the reactions have rale constants considerably below expected diffusion-controlled limits for the proton transfers in the thermodynamically favorable direction, and several of the reactions, including the identity reactions of carboxylic acids, have kinetic deuterium isotope effects, kH/kD, between 0.8 and 1.3. For reactions of N,N-dimethylbenzylammonium ion with several phenoxides, carboxylates, and solvent, the rate constants for transfers in the unfavorable directions show a reasonable Bronsted correlation with β ≈ 1 and a reasonably constant reverse rate constant of ≈3 × 106 M-1 s-1. The data clearly indicate that the proton-transfer step is not rate-limiting in these reactions. Most likely, desolvation is involved in the rate-limiting steps, but the rate constants are not simple functions of acidities as might have been expected if hydrogen bonding of acid to solvent were the major factor involved in the solvation Other factors, particularly dispersion interactions of solvent with solutes, are discussed. We suggest that the formation of an acid-base complex with proper orientation to allow contact between the proton and the basic site is rate-determining and involves desolvation along with detailed steric interactions of the acid-base pair.
- Ritchie, Calvin D.,Lu, Shanzheng
-
p. 7748 - 7756
(2007/10/02)
-
- Process for the preparation of zomepirac and related compounds
-
Zomepirac and its analogs have been prepared from a 5-aroyl-3-hydroxycarbonyl-4-substituted pyrrole-2-acetic acid via acidic decarboxylation.
- -
-
-
