- In situ generation of difluoromethyl diazomethane for [3+2] cycloadditions with alkynes
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A novel approach to agrochemically important difluoromethyl-substituted pyrazoles has been developed based on the elusive reagent CF2HCHN2, which was synthesized (generated in situ) for the first time and employed in [3+2] cycloaddition reactions with alkynes. The reaction is extremely practical as it is a one-pot process, does not require a catalyst or the isolation of the potentially toxic and explosive gaseous intermediate, and proceeds in a common solvent, namely chloroform, in air. The reaction is also scalable and allows for the preparation of the target pyrazoles on gram scale. A new reagent: The elusive chemical reagent CF2HCHN2 was generated in situ for the first time and further reacted with alkynes in a [3+2] cycloaddition reaction. This transformation constitutes a novel and efficient approach to agrochemically important difluoromethylated pyrazoles.
- Mykhailiuk, Pavel K.
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Read Online
- Synthesis and Biological Activity of Fluoroalkylamine Derivatives of Narcotic Analgesics
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N-Ethyl-, N-(2-fluoroethyl)-, N-(2,2-difluoroethyl)-, and N-(2,2,2-trifluoroethyl)-substituted normeperidine (1b-e) and normetazocine (2b-e) derivatives were prepared.The analgesic activities of the compounds were determined in mice.Opiate receptor binding studies, in the presence and absence of sodium ion, were carried out.The antagonist activities of normetazocine derivatives were studied in monkeys.These were further examined in the isolated guinea pig ileum for agonist activity.These pKa values were measured in vivo agonist activity was lost with the weakly bas ic derivatives.For the normetazocine derivatives, opiate receptor binding data were consistent with guinea pig ileum agonist potency and mouse vas deferens antagonist potency but not in vivo data.Opiate receptor binding was reduced for the less basic normetazocine derivatives.In the normeperidine series, there was no apparent direct relationship between pKa and opiate receptor binding.However, a relationship involving the hydrophobic character of the N-substituent is discussed.The N-(2-fluoroethyl) derivatives in both series were found to cause convulsions in rats at doses of 40-45 mg/kg ip.Elevated serum citrate levels were found in these rats, implicating in vivo oxidative deamination of the N-(fluoroalkyl) substituent to fluoroacetate.
- Reifenrath, William G.,Roche, Edward B.,Al-Turk, Walid A.,Johnson, Howard L.
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- Gas phase hydrogenolysis of methyl difluoroacetate to 1,1-difluoroethanol over Ru/C catalysts
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Ru/C catalysts were prepared by an impregnation method and their catalytic properties were tested for hydrogenolysis methyl difluoroacetate to difluoroethanol. The catalysts were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), CO chemisorption and H 2 temperature-programmed reduction (H2-TPR). The effects of reaction temperature, Ru content and reduction temperature of the Ru/C catalysts on the reaction were investigated. It was found that with increasing Ru contents in the Ru/C catalysts, the methyl difluoroacetate conversion, the selectivity to difluoroethanol and the TOF value first increased and then decreased. A 3Ru/C catalyst reduced at 400 °C exhibited the highest selectivity to difluoroethanol (93.5%) and the highest activity (39.5%). It was also found that the Ru/C catalyst showed a good stability of catalytic hydrogenolysis of methyl difluoroacetate within 100 h.
- Zheng, Su-Zhen,Cao, Xiao-Yan,Zhou, Qiang,Wang, Shu-Hua,Hu, Geng-Shen,Lu, Ji-Qing,Luo, Meng-Fei,Wang, Yue-Juan
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Read Online
- Hydrogen Bonding in Low-Temperature Matrices: 1. Proton Donor Abilities of Fluoroalcohols. Comparative Infrared Studies of ROH...O(CH3)2 Complex Formation in the Gas Phase, in CCl4 Solution, and in Solid Argon
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The proton donor-acceptor complexes formed by a series of fluoroalcohols with systematically increasing acidity (pKa's from 14.5 to 5.4) have been studied with dimethyl ether (DME) as a reference base in argon matrices, in CCl4 solutions, and in the gas phase.The intermolecular bond formation O-H...O is discussed on the basis of changes of the O-H stretching absorptions in the infrared spectra.A stepwise increase of the proton donor abilities of the fluoroalcohols is achieved by successively introducing fluorine in β-position of the alcohols as indicated by the increasing frequency shift of the O-H stretching vibrations in the O-H...O complexes.The observed frequency shifts Δν increases as one passes from the gas phase to CCl4 solutions and argon matrices.Data for ΔH0, ΔS0, and ΔG0 have been derived from the solution measurements on the basis of the temperature-dependent intensity changes of the "free" O-H stretching bands.A comparison of the O-H stretching frequencies of the alcohol monomers obtained from the three phases has also been made.The small shifts observed in argon matrices on the order of 19 +/- 4 cm-1 are characteristic for weak interactions of the van der Waals type.The solvent shift in CCl4 is about twice as high and was found to be on the order of 45 +/- 8 cm-1, indicating a much stronger interaction with the solute molecules.It is concluded that it is advantageous, where possible, to study a particular hydrogen-bonded system in different phases in order to get a deeper insight into intermolecular interactions ranging from very weak to very strong and to distinguish hydrogen bond interaction in condensed phases from other intermolecular forces or environmental effects.
- Schrems, Otto,Oberhoffer, Helmut M.,Luck, Werner A. P.
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Read Online
- Method for preparing 2,2-difluoroethanol
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The invention discloses a method for preparing 2,2-difluoroethanol. The method for preparing 2,2-difluoroethanol comprises the following steps: step (i): performing transesterification on 2,2-difluoroethyl acetate in the presence of ethanol and optionally a base.
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Paragraph 0069-0074
(2021/04/14)
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- Method for synthesizing 2,2-difluoroethanol from R142
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The invention provides a method for synthesizing 2,2-difluoroethanol from R142. The method comprises the following steps: reacting the R142 with alkali metal formate or alkali metal acetate to preparean intermediate; and reacting the intermediate with alcohol under the catalysis of an oxide carrier loaded metal element catalyst to prepare 2,2-difluoroethanol. In the oxide carrier loaded metal element catalyst, the oxide carrier is aluminum oxide, magnesium oxide or zirconium dioxide, and the metal element is one or a combination of two or more of Mg, Ca, Sr, Ba, Na, K, Rb, Cs, La, Nd, Y and Ce. The oxide carrier loaded metal elements are used as the catalyst, so that the catalyst can be recycled, no alkaline waste liquid is generated, and the catalyst is environment-friendly and low in cost; and the reaction temperature is proper, side reactions are few, and the yield and purity of the obtained target product are high.
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Paragraph 0047; 0051-0052
(2020/05/02)
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- Engineering Catalysts for Selective Ester Hydrogenation
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The development of efficient catalysts and processes for synthesizing functionalized (olefinic and/or chiral) primary alcohols and fluoral hemiacetals is currently needed. These are valuable building blocks for pharmaceuticals, agrochemicals, perfumes, and so forth. From an economic standpoint, bench-stable Takasago Int. Corp.'s Ru-PNP, more commonly known as Ru-MACHO, and Gusev's Ru-SNS complexes are arguably the most appealing molecular catalysts to access primary alcohols from esters and H2 (Waser, M. et al. Org. Proc. Res. Dev. 2018, 22, 862). This work introduces economically competitive Ru-SNP(O)z complexes (z = 0, 1), which combine key structural elements of both of these catalysts. In particular, the incorporation of SNP heteroatoms into the ligand skeleton was found to be crucial for the design of a more product-selective catalyst in the synthesis of fluoral hemiacetals under kinetically controlled conditions. Based on experimental observations and computational analysis, this paper further extends the current state-of-the-art understanding of the accelerative role of KO-t-C4H9 in ester hydrogenation. It attempts to explain why a maximum turnover is seen to occur starting at 25 mol % base, in contrast to only 10 mol % with ketones as substrates.
- Dub, Pavel A.,Batrice, Rami J.,Gordon, John C.,Scott, Brian L.,Minko, Yury,Schmidt, Jurgen G.,Williams, Robert F.
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p. 415 - 442
(2020/03/04)
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- SYNTHESIS OF FLUORO HEMIACETALS VIA TRANSITION METAL-CATALYZED FLUORO ESTER AND CARBOXAMIDE HYDROGENATION
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This application is directed to use of transition metal-ligand complexes to hydrogenate fluorinated esters and carboxamides into fluorinated hemiacetals. Methods for synthesis of certain ligands are also provided.
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Paragraph 0237-0238; 0259-0260
(2020/11/24)
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- Diaminodiphosphine tetradentate ligand and ruthenium complex thereof, and preparation methods and applications of ligand and complex
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The invention discloses a diaminodiphosphine tetradentate ligand and a ruthenium complex thereof, and preparation methods and applications of the ligand and the complex, and provides a ruthenium complex represented by a formula I, wherein L is a diaminodiphosphine tetradentate ligand represented by a formula II, and X and Y are respectively and independently chlorine ion, bromine ion, iodine ion,hydrogen negative ion or BH4. According to the present invention, the ruthenium complex exhibits excellent catalytic activity in the catalytic hydrogenation reactions of ester compounds, has high yield and high chemical selectivity, is compatible with conjugated and non-conjugated carbon-carbon double bond, carbon-carbon triple bond, epoxy, halogen, carbonyl and other functional groups, and hasgreat application prospects.
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Paragraph 0312-0315
(2019/11/04)
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- Difluoroethanol synthesis method using 2,2-difluoro-1-chloroethane as raw material
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The invention relates to a difluoroethanol synthesis method using 2,2-difluoro-1-chloroethane as a raw material, and aims to solve the problems that in the prior art, the reaction conditions are strict, and the product yield and purity are low. According to the method, 2,2-difluoro-1-chloroethane and metal acetate are taken as the raw materials, 2,2-difluoro-1-chloroethane and metal acetate carryout reactions in a solvent to generate difluoroethyl acetate, and then under the action of a sulfuric acid supported silicon dioxide catalyst, difluoroethyl acetate and alcohols carry out transesterification to generate difluoroethanol. The method has the advantages of mild reaction conditions, high product yield, and high purity. The catalyst can be repeatedly used. The method is suitable for industrial production.
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Paragraph 0020; 0023; 0026; 0029; 0032
(2018/06/26)
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- Synthetic method of 2,2-difluoroethanol
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The invention discloses a synthetic method of 2,2-difluoroethanol, which solves the problems in the prior art that the synthetic process is complicated, and a product is difficult to separate. The method adopts 2,2-difluoroethyl ethyl (meth)ate as a raw material to carry out one-step reaction with metal hydroxide to generate difluoroethanol under an anhydrous condition. The synthetic method is fewer in procedures, simple in process, and suitable for a process of adopting fluorine-containing halohydrocarbon as a raw material to firstly generate fluorine ester and then to synthesizing fluoro-alcohol.
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Paragraph 0015; 0016; 0018; 0020
(2018/07/07)
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- Method for synthesizing difluoroethanol
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The invention relates to a method for synthesizing difluoroethanol, and aims to solve the problems of multiple steps, complicated process, low product purity and low yield in the prior art. The methodcomprises the following steps: (1) adding gamma-butyrolactone and alkali metal hydroxide into a reaction kettle under anhydrous and vacuum conditions; (2) feeding 2,2-difluoro-1-halothane, and then quickly heating to reaction temperature for reaction; (3) filtering, rectifying and drying obtained reaction liquid to obtain a difluoroethanol product. The difluoroethanol synthesized by the method has the purity more than or equal to 99.9 percent and the yield more than or equal to 92 percent.
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Paragraph 0017-0026
(2018/06/04)
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- Difluoroethanol synthesis process
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The invention relates to a difluoroethanol synthesis process. The difluoroethanol synthesis process comprises the following steps: firstly adding gamma-butyrolactone and an alkali metal hydroxide intoa reactor, introducing 2,2-difluoro-1-halothane, rapidly heating to the reaction temperature, processing a feed liquid through a centrifugal machine after the reaction is finished, rectifying an obtained clear liquid in a separation tower to obtain difluoroethanol; centrifuging, enabling a solid to enter a washing kettle, washing with methyl alcohol or ethanol, processing a washing liquid throughthe centrifugal machine, drying an obtained solid through a drier to obtain potassium chloride, conducting vacuum distillation on the centrifuged clear liquid in a distilling kettle, recycling methylalcohol or ethanol, obtaining a solid of potassium hydroxybutyrate after distilling, drying through the drier, and returning to a reaction system to continue to react. By adopting the process, the operation is simple, the economic efficiency is relatively high, and the process is suitable for large-scale production.
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Paragraph 0013-0015; 0017; 0020; 0023; 0026
(2018/06/04)
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- Preparation method and device of difluoroethanol
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The invention relates to a preparation method and device of difluoroethanol. The preparation method of the difluoroethanol comprises the following steps: enabling a solvent to react with potassium hydroxide in a closed reaction kettle to generate an intermediate product; slowly introducing excess 2-chloro-1,1-difluoroethane into the reaction kettle; after reacting for a certain period of time, separating and purifying a product to obtain high-purity 2,2,-difluoroethanol. According to the preparation method provided by the invention, the difluoroethanol is prepared from 2-chloro-1,1-difluoroethane; the raw material, which is a byproduct of 1,-chloro-1,1-difluoroethane, is easily available and has low cost; the reaction conditions are mild, few byproducts are produced, and environmental pollution is avoided.
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Paragraph 0025-0034; 0035; 0039; 0040; 0041; 0043; 0046
(2018/04/03)
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- SUBSTITUTED HETEROARYL COMPOUNDS AND METHODS OF USE
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The present invention provides novel heteroaryl compounds, pharmaceutical acceptable salts and formulations thereof. They are useful in preventing, managing, treating or lessening the severity of a protein kinase-mediated disease. The invention also provides pharmaceutically acceptable compositions comprising such compounds and methods of using the compositions in the treatment of protein kinase-mediated disease.
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Paragraph 0463
(2017/04/14)
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- Substituted heteroaryl compound and composition thereof, and uses of substituted heteroaryl compound and composition thereof
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The present invention provides a substituted heteroaryl compound and a composition thereof, and uses of the substituted heteroaryl compound and the composition, wherein the compound is a compound represented by a formula (I) or a stereoisomer, a tautomer, a nitrogen oxide, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug of the compound represented by the formula (I). The present invention further provides a pharmaceutical composition containing the compound, wherein the pharmaceutical composition can regulate activity of protein kinases, particularly Aurora kinases and JAK kinases, and can be used for prevention, treatment, therapy and alleviation of protein kinases, particularly Aurora kinases and JAK kinase activity mediated diseases or disorders.
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Paragraph 1032; 1033; 1034; 1035
(2017/04/29)
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- Manufacturing method of [alpha],[alpha]-difluoroacetaldehyde
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The objective of the present invention is to provide a manufacturing method of [alpha],[alpha]-difluoroacetaldehyde capable of being industrially easily implemented without special equipment. The manufacturing method of [alpha],[alpha]-difluoroacetaldehyde or hydrate thereof or hemiacetal is characterized in that difluoroacetate represented by the general formula CF2HCOOR1[R1 represents an alkyl group or substituted alkyl group] reacts with tetrahydridoborate which serves as a hydride reducing agent in the presence of a protic solvent and alkali.
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Paragraph 0098; 0099; 0101; 0103; 0106; 0108; 0110; 0112
(2017/09/26)
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- Method for preparing difluoroethanol through catalytic hydrogenation
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The invention provides a method for preparing difluoroethanol through catalytic hydrogenation. The method has the beneficial effects that hydrogenation reduction reaction is carried out by using ethyl chlorodifluoroacetate as the raw material, a Pd/C as a catalyst, triethylanmine as an acid-binding agent and ethanol as a solvent; the atom F has higher electronegativity and HF can not be generated in the ethyl chlorodifluoroacetate hydrogenation process, but the C-Cl bond is easy to hydrogenate and HCl is easy to generate, thus neutralizing generated HCl by adding the acid-binding agent triethylanmine, propelling reaction to be carried out positively and increasing the conversion rate of ethyl chlorodifluoroacetate; on the other side, used in ester hydrogenation reaction, the Pd/C catalyst has good characteristics of low hydrogen-ester ratio, high raw material conversion rate, high alcohol selectivity, stable catalyst, and the like; and therefore, the method has the effect of solving the problems that the reaction process in the traditional ester hydrogenation process is complex, is high in investment and is not suitable for small-scale production in the fine chemical industry field.
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Paragraph 0037-0038
(2017/06/02)
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- MANUFACTURING METHOD OF α,α-DIFLUORO ACETALDEHYDE
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PROBLEM TO BE SOLVED: To provide an effective industrial manufacturing method of α,α-difluoro acetaldehydes. SOLUTION: The disclosed manufacturing method of α,α-difluoro acetaldehydes can be achieved by reacting α,α-difluoroacetic acid esters with hydrogen gas (H2) in presence of a ruthenium-catalyst and a base. By employing specific reaction conditions (catalyst, base, pressure or the like), α,α-difluoro acetaldehydes can be manufactured at high conversion rate and high selectivity. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0067-0068; 0069
(2017/09/19)
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- Method for preparing 2-difluoroethanol through liquid phase hydrogenation, catalyst and preparing method of catalyst
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The invention relates to a method for preparing 2-difluoroethanol through liquid phase hydrogenation, a catalyst and a preparing method of the catalyst. Under the conditions of a low temperature and low pressure, the carbon nano tube carried type catalyst is used for carrying out a hydrogenation reaction on 2-difluoroacetic acid ester, a reaction product is collected and rectified, and 2-difluoroethanol can be obtained. The invention further relates to the carbon nano tube carried type catalyst and the preparing method thereof. The method for preparing 2-difluoroethanol through liquid phase hydrogenation, the catalyst and the preparing method of the catalyst have the advantages that the reaction conditions are mild, the catalyzing activity is high, and the selectivity of the product 2-difluoroethanol is high.
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Paragraph 0042-0043
(2017/03/14)
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- Method for preparing 2,2-difluoroethanol
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The invention discloses a method for preparing 2,2-difluoroethanol. The method comprises the following steps: taking acetate and 1-chlorine-2,2-difluoroethane as a raw material and high-boiling point alcohol as a solvent, using acetic acid to adjust a pH value, according to a specific rate of charge, reacting the materials under specific temperature gradient to prepare 2,2-difluoroethanol. The method uses the high-boiling point solvent for replacing the traditional sulfoxides and amides solvents, 2,2-difluoroethanol is prepared by an one-step method, the raw materials have the advantages of low cost and easy acquisition, and the method has the advantages of simple process, easy operation, high conversion rate, high yield, and little by-products, and is suitable for industrial production. The purity of 2,2-difluoroethanol is greater than or equal to 98.5, the conversion rate is greater than or equal to 96%, and the yield is greater than or equal to 92%.
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Paragraph 0014
(2017/06/13)
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- Alpha,Alpha-Difluoroacetaldehyde Production Method
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A production method of α,α-difluoroacetaldehyde according to the present invention includes reaction of an α,α-difluoroacetic acid ester with hydrogen gas (H2) in the presence of a ruthenium catalyst. It is possible to selectively obtain α,α-difluoroacetaldehyde as a partially reduced product of the hydrogenation reaction by the adoption of specific reaction conditions (in particular, reaction solvent and reaction temperature). This hydrogenation process can be alternative to the industrially unpractical hydride reduction process.
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Paragraph 0082; 0083; 0084
(2016/01/30)
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- PROCESS FOR PREPARING 2,2-DIFLUOROETHANOL
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Process for preparing 2,2-difluoroethanol, comprising the following steps: reacting 1-chloro-2,2-difluoroethane with an alkali metal salt of formic acid or acetic acid in a suitable solvent to give the corresponding 2,2-difluoroethyl formate or 2,2-difluoroethyl acetate, and transesterifying the 2,2-difluoroethyl formate or 2,2-difluoroethyl acetate from step (i) in the presence of an alcohol and optionally of a base.
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Paragraph 0040; 0041; 0042
(2014/09/03)
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- PROCESS FOR PRODUCING A-FLUOROALDEHYDES
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A production process of an α-fluoroaldehyde according to the present invention includes reaction of an α-fluoroester with hydrogen gas (H2) in the presence of a ruthenium complex. It is possible in the present invention to allow relatively easy industrial production of the α-fluoroaldehyde and to directly obtain, as stable synthetic equivalents of the α-fluoroaldehyde, not only a hydrate (as obtained by conventional techniques) but also a hemiacetal that is easy to purify and is of high value in synthetic applications. The present invention provides solutions to all problems in the conventional techniques and establishes the significantly useful process for production of the α-fluoroaldehyde.
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Paragraph 0063
(2014/06/24)
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- METHOD FOR PRODUCING -FLUOROALCOHOL
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A production method of a β-fluoroalcohol includes performing a reaction of an α-fluoroester with hydrogen gas (H2) in the presence of a specific ruthenium complex (i.e. a ruthenium complex of the general formula [2], preferably a ruthenium complex of the general formula [4]). This production method can employ a suitable hydrogen pressure of 1 MPa or less by the use of such a specific ruthenium complex and does not require a high-pressure gas production facility when put in industrial practice. In addition, this production method can remarkably reduce the amount of catalyst used therein (to e.g. a substrate/catalyst ratio of 20,000) in comparison to the substrate/catalyst ratio conventional reduction of α-fluoroalcohol. It is possible by these reduction in hydrogen pressure and catalyst amount to largely reduce the production cost of the β-fluoroalcohol.
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Paragraph 0062
(2013/11/05)
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- Method for Producing Difluoroacetyl Chloride
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A production method of difluoroacetyl chloride according to the present invention includes a chlorination step of bringing a raw material containing at least either a 1-alkoxy-1,1,2,2-tetrafluoroethane or difluoroacetyl chloride into contact with calcium chloride at a reaction enabling temperature. A production method of 2,2-difluoroethyl alcohol according to the present invention includes a catalytic reduction step of causing catalytic reduction of the difluoroacetyl chloride obtained by the above production method. By these methods, the difluoroacetyl fluoride can be efficiently converted to the difluoroacetyl chloride and to the 2,2-difluoroethyl alcohol.
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Paragraph 0088; 0089
(2013/03/26)
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- Practical selective hydrogenation of α-fluorinated esters with bifunctional pincer-type ruthenium(II) catalysts leading to fluorinated alcohols or fluoral hemiacetals
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Selective hydrogenation of fluorinated esters with pincer-type bifunctional catalysts RuHCl(CO)(dpa) 1a, trans-RuH2(CO)(dpa) 1b, and trans-RuCl2(CO)(dpa) 1c under mild conditions proceeds rapidly to give the corresponding fluorinated alcohols or hemiacetals in good to excellent yields. Under the optimized conditions, the hydrogenation of chiral (R)-2-fluoropropionate proceeds smoothly to give the corresponding chiral alcohol without any serious decrease of the ee value.
- Otsuka, Takashi,Ishii, Akihiro,Dub, Pavel A.,Ikariya, Takao
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supporting information
p. 9600 - 9603
(2013/07/26)
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- PRACTICAL METHOD FOR REDUCING ESTERS OR LACTONES
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Esters and lactones can be respectively reduced to alcohols and diols in the presence of the Group 8 (VIII) transition metal complex, base and hydrogen gas (H2). An extremely practical reduction method can be provided by preferable combinations of the Group 8 (VIII) transition metal complex, the base, a used amount of the base, a pressure of hydrogen gas and a reaction temperature. This method is used in place of hydride reduction and is a useful method by which design of highly active catalysts can be relatively easily made while a high productivity can be expected.
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Page/Page column 16
(2011/04/18)
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- PROCESS FOR THE PREPARATION OF FLUORINE CONTAINING ORGANIC COMPOUND
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Process for the preparation of a fluorine containing organic molecule, which process comprises the steps of a) preparation of a compound of the formula (I) wherein R1, R2 and R3 are independently hydrogen, fluor or an optionally fluorinated hydrocarbon group by feeding a compound of the formula (II) wherein R1, R2 and R3 are defined as above, and hydrogen bromide into a reaction zone, thereby producing a reaction mixture containing the compound of formula (II) and hydrogen bromide and irradiating said reaction mixture with UV light, and b) substituting the bromo atom in the compound of the formula (I) with another functional group to obtain the fluorine containing organic molecule. The invention allows also in particular for obtaining substantially anhydrous fluoroalcohols. The preparation of alcohols analogous to the bromides of formula (I) from the corresponding esters is also disclosed.
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Page/Page column 12
(2009/05/29)
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- Production of Difluoroethanol
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Difluoroethanol is produced by hydrogenation, in the presence of an effective amount of a catalyst containing at least one element of Group VIII of the Periodic Table deposited onto a solid, acidic mineral support, of an acetyl halide having the following formula (I), in which formula X is a halogen atom other than a fluorine atom:
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Page/Page column 2
(2009/09/08)
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- Process for the manufacture of fluorinated alcohols
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Process for the manufacture of fluorinated alcohols having the formula ???????? CnFmH2n+1-mCH2OH?????(1) wherein n is 1 or 2; and m is an integer from 1 to 5, but not larger than 2n+1; by hydrogenating the corresponding fluorinated carboxylic acids and/or their derivates having the formula ???????? CnFmH2n+1-mCOR?????(2) wherein n and m have the above meanings and R represents OH, Cl, Br, F, and OR', wherein R' is a hydrocarbon rest, in the presence of a catalyst and of water but excluding the hydrogenation of trifluoroacetic acid to form trifluoroethanol.
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Page/Page column 3
(2008/06/13)
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- Spectrokinetic study of the reaction system of 2NO2?N 2O4 with some fluorinated derivatives of ethanol and propanols between 293-358 K in the gas phase
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The gas phase kinetics of the reversible reactions between nitrogen tetroxide and some fluorinated alcohols in the reaction system 2NO 2?N2O4 (1, 2) N2O4 + ROH?RONO+ + HNO3 (3, 4) have been studied by UV-Vis spectrophotometry to follow the NO2 decay. The products - RONO (R = CH2FCH2, CHF2CH2, CF 3CH2, CHF2CF2CH2, CF 3CF2CH2, CF3CHCF3) - were identified by their UV spectra and the values of the maxima UV absorption cross sections were determined in the range 320-400 nm. The rate constants for the forward reaction are 10-19k3av/cm 3molec-1s-1 9.7±1.5; 2.5±0.4; 1.8±0.3; 23±3.5, 2.3±0.3, 0.2±0.03 and for the reverse reaction 10-19k4av/cm 3molec-1s-1 4.6±0.7; 5.5±0.8; 4.9±0.7; 9.1±1.4; 7.7±1.2; 23±3.5 at 298 K for the reaction with 2-fluoroethanol, 2,2-difluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol, 2,2,3,3,3-pentafluoro-1-propanol and 1,1,1,3,3,3-hexafluoro-2-propanol, respectively, were derived by the computer simulation of monitored NO2 decay profiles. The temperature dependence of the bimolecular rate constants k3 and k4 were studied in the temperature range 293-358 K and the activation energy for the forward E3 and for the reverse E4 reaction were derived. From the observed temperature dependence of the equilibrium constants K3,4, expressed in terms of the van't Hoff equation, the thermochemical parameters for all reactions studied were estimated.
- Wojcik-Pastuszka,Golonka,Ratajczak
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p. 1559 - 1574
(2008/02/04)
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- The effect of fluoromethyl groups on the diastereoselectivity in the electrophilic alkylation
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The effect of fluoromethyl groups on the diastereoselectivity in the electrophilic alkylation is described. In particular, the electrophilic alkylation of enolates with a trifluoromethyl group was proceeded with highly diastereofacial selectivity based on the steric and/or electrostatic effect of substituent with strong electron withdrawing.
- Tamura, Kenji,Yamazaki, Takashi,Kitazume, Tomoya,Kubota, Toshio
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p. 918 - 930
(2007/10/03)
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- Difluoridnated Carbaacyclonucleosides: Synthesis and Evaluation of Antiviral Activity
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The synthesis of 4-benzoyloxy-5,5-difluoropentan-1-ol from ethyl difluoroacetate is described. Condensation with pyrimidine bases gave carbaacyclonucleosides. The uracil (8d), cytosine (9) and thymine (10c) congeners were evaluated, and found inactive, in a large variety of antiviral assays.
- Lewis, Maureen,Clercq, Erik De
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p. 844 - 856
(2007/10/03)
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- EXPERIMENTAL STUDIES OF THE ANOMERIC EFFECT. PART IV. CONFORMATIONAL EQUILIBRIA DUE TO RING INVERSION IN TETRAHYDROPYRANS SUBSTITUTED AT POSITION 2 BY THE GROUPS ETHOXY, 2'-FLUOROETHOXY, 2',2'-DIFLUOROETHOXY, AND 2',2',2'-TRIFLUOROETHOXY
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Equilibrium constants (K) for ring inversion equilibria in 2-(RO)-tetrahydropyrans (R = Et, CH2CH2F, CH2CHF2, CH2CF3) have been determined from 13C nmr spectra recorded at 145-160 K in CD2Cl2 and CFCl3/CDCl3 (85/15 by volume).Additional values of K were obtained at 250-270 K from the acid-catalysed equilibration of cis- and trans-2-(RO)-4-methyl-tetrahydropyran (R as above).Plots of lnK against T-1 gave values for ΔH0a->e of -0.26, -0.12, -0.05 and 0.13 kcal mol-1 for R = Et, CH2CH2F, CH2CHF2 and CH2CF3, respectively, in CD2Cl2.The corresponding values of ΔH0a->e for CFCl3/CDCl3 as solvent were -0.58, -0.15, -0.07 and 0.21 kcal mol-1, respectively.The derived ΔS0a->e values were -2.33, -2.22, -2.25 and -2.24 cal K-1mol-1, respectively, in CD2Cl2 and -4.65, -3.37, -3.30 and -3.03 cal K-1mol-1, respectively, in CFCl3/CDCl3. The trends in ΔH0 values are attributed to modifications of anti-periplanar n->o* stabilisation (itself partly responsible for endo- and exo-anomeric effects) which occur as the number of electronegative fluorine substituents increases.For all substituents, axial conformations are the most abundant in the temperature range 120 K to infinite.However, this finding is a consequence of the higher entropy of axial conformations; in at least two cases (R = Et and CH2CH2F) it is the equatorial conformation which has the lower enthalpy.The results confirm the importance of studying conformational equilibria over a wide range of temperature.
- Booth, Harold,Readshaw, Simon A.
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p. 2097 - 2110
(2007/10/02)
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