- Synthesis of analogs of farnesyl diphosphate
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Syntheses of analogs of farnesyl diphosphate (FPP) bearing substitutions at C3 are described. The mono-, di-, and trifluoromethylFPP derivatives were prepared by alkylation of appropriately substituted acetoacetates with geranyl bromide, followed by decarboxylation to obtain fluorinated ketones and a Wittig condensation to give the farnesyl skeleton. A similar sequence was used to synthesize 13-desmethylFPP.
- Dolence,Poulter
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Read Online
- Synthesis of fungicidally active succinate dehydrogenase inhibitors with novel difluoromethylated heterocyclic acid moieties
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Abstract: Novel fungicidally active succinate dehydrogenase inhibitors have been prepared, which either carry a difluoromethyl and methyl-bearing pyrazoline, pyrrole, or thiophene ring in the acid component, mimicking similar-substituted pyrazole carboxamides. As five-membered heterocyclic systems with such a special substitution pattern are barely known, unique synthesis routes had to be developed, which rely, e.g., on the van Leusen pyrrole synthesis and the halogen dance reaction. Synthesis and biological activity against selected Ascomycete pathogens of these difluoromethylated pyrazoline, pyrrole, and thiophene derivatives are reported.
- Walter, Harald,Lamberth, Clemens,Corsi, Camilla
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Read Online
- Design, Synthesis, and Pesticidal Activities of Pyrimidin-4-amine Derivatives Bearing a 5-(Trifluoromethyl)-1,2,4-oxadiazole Moiety
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It is important to discover new pesticides with new modes of action because of the increasing evolution of pesticide resistance. In this study, a series of novel pyrimidin-4-amine derivatives containing a 5-(trifluoromethyl)-1,2,4-oxadiazole moiety were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR, and HRMS. Bioassays indicated that the 29 compounds synthesized possessed excellent insecticidal activity against Mythimna separata, Aphis medicagini, and Tetranychus cinnabarinus and fungicidal activity against Pseudoperonospora cubensis. Among these pyrimidin-4-amine compounds, 5-chloro-N-(2-fluoro-4-(5-(trifluoromethyl)-1,2,4-oxadiazol-3-yl)benzyl)-6-(1-fluoroethyl)pyrimidin-4-amine (U7) and 5-bromo-N-(2-fluoro-4-(5-(trifluoromethyl)-1,2,4-oxadiazol-3-yl)benzyl)-6-(1-fluoroethyl) pyrimidin-4-amine(U8) had broad-spectrum insecticidal and fungicidal activity. The LC50 values were 3.57 ± 0.42, 4.22 ± 0.47, and 3.14 ± 0.73 mg/L for U7, U8, and flufenerim against M. separata, respectively. The EC50 values were 24.94 ± 2.13, 30.79 ± 2.21, and 3.18 ± 0.21 mg/L for U7, U8, and azoxystrobin against P. cubensis, respectively. The AChE enzymatic activity testing revealed that the enzyme activities of compounds U7, U8, and flufenerim are 0.215, 0.184, and 0.184 U/mg prot, respectively. The molecular docking results of compounds U7, U8, and flufenerim with the AChE model demonstrated the opposite docking mode between compound U7 or U8 and positive control flufenerim in the active site of AChE. The structure-activity relationships are also discussed. This work provided excellent pesticide for further optimization. Density functional theory analysis can potentially be used to design more active compounds.
- Cheng, Long,Liu, Xing-Hai,Wen, Yong-Hui,Wu, Ning-Jie,Xu, Tian-Ming
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p. 6968 - 6980
(2021/07/19)
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- Cu-Mediated Expeditious Annulation of Alkyl 3-Aminoacrylates with Aryldiazonium Salts: Access to Alkyl N2-Aryl 1,2,3-Triazole-carboxylates for Druglike Molecular Synthesis
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Alkyl N-aryl 1,2,3-triazole-carboxylates are important molecules or intermediates in medicinal chemistry, but the synthesis of N2-aryl counterparts remains elusive. Herein, we describe a Cu-mediated annulation reaction of alkyl 3-aminoacrylates with aryldiazonium salts, both of which are readily available substrates. Furthermore, alkyl 2-aminoacrylates are also viable substrates. Diverse alkyl N2-aryl 1,2,3-triazole-carboxylates and their analogues can be rapidly prepared under mild conditions. Especially, this protocol allows one to access several druglike variants of carbonic anhydrase inhibitors and celecoxib.
- Liu, Hao-Nan,Cao, Hao-Qiang,Cheung, Chi Wai,Ma, Jun-An
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supporting information
p. 1396 - 1401
(2020/02/22)
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- INHIBITORS OF LEUCINE RICH REPEAT KINASE 2
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The present invention relates to novel compounds that inhibit LRRK2 kinase activity, to processes for their preparation, to compositions containing them and to their use in the treatment of or prevention of diseases associated with or characterized by LRRK2 kinase activity, for example Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis (ALS).
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Page/Page column 129
(2019/02/02)
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- A laminated material for catalytic synthesis of difluoro-acetyl-acetic acid ethyl ester
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The invention discloses a method for synthesizing ethyl 4,4-difluoroacetoacetate in a catalyzed mode through layered materials. The method includes the following steps: 1, a divalent and trivalent metal salt solution and a sodium hydroxide and sodium carbonate mixed solution are rapidly mixed to prepare multielement hydrotalcite, the multielement hydrotalcite is roasted to be added into a fluoride-salt saturation aqueous solution, the mixture is stirred, filtered, washed and dried to be roasted under the nitrogen condition, and catalysts are obtained; 2, ethyl acetate, ethyl difluoroacetate and the catalysts are added into a four-opening flask, an ethyl alcohol and ethyl acetate mixture is evaporated after temperature rising, stirring and reacting are carried out, cooling is carried out, catalysts are filtered and recycled, filtrate is acidized, cooled and filtered, and pressure reduction rectification is carried out on the filtrate to obtain the ethyl 4,4-difluoroacetoacetate; 3, the recycled catalysts are sufficiently washed through solvents and roasted to be added into a fluoride-salt saturation aqueous solution, the mixture is stirred, filtered, washed and dried to be roasted under the nitrogen condition, and the catalysts are regenerated. The method has the advantages that the yield is high, the catalysts can be recycled, and the method is safe and environmentally friendly.
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Paragraph 0031-0033
(2017/08/15)
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- A 4, 4 - difluoro-acetyl-acetic acid alkyl ester preparation method
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The invention discloses a method for preparing alkyl 4,4-difluoroacetylacetate. The method has the advantages of easily available raw materials, simple process flow, safety in operation and high yield. The method comprises the following steps: (1) carrying out hydrolysis reaction on 1,1,2,2-tetrafluoroethyl ether used as a raw material and water in an acid and separating to obtain ethyl difluoroacetate and hydrogen fluoride; (2) reacting ethyl difluoroacetate obtained in the step (1) and alkyl acetate in the presence of an alkaline catalyst to obtain 1,1-difluoro-2-butenoic acid alkyl ester-2-hydroxy salt; and (3) neutralizing 1,1-difluoro-2-butenoic acid alkyl ester-2-hydroxy salt obtained in the step (2) and hydrogen fluoride to obtain alkyl 4,4-difluoroacetylacetate.
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Paragraph 0055
(2017/08/25)
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- SUBSTITUTED 3-AZABICYCLO[3.1.0]HEXANES AS KETOHEXOKINASE INHIBITORS
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Provided herein are substituted 3-azabicyclo[3.1.0]hexanes as ketohexokinase inhibitors, processes to make said compounds, and methods comprising administering said compounds to a mammal in need thereof.
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Paragraph 0248
(2017/07/14)
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- 3-difluromethyl-1-methyl-pyrazole-4-formic acid and synthetic method thereof
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The present invention relates to the field of chemical industry, and more specifically, relates to 3-difluromethyl-1-methyl-pyrazole-4-formic acid and a synthetic method thereof, the synthetic method comprises the steps: DFKE synthesis; DFVKE synthesis; DFPE synthesis; and DFPA synthesis. The synthesis method has the advantages of cheap and easily-obtained materials, greenness, environmental-friendliness, simple reaction conditions, less impurities and high yield, the prepared 3-difluromethyl-1-methyl-pyrazole-4-formic acid has high quality and high purity, and the yield is 90% or more.
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Paragraph 0023; 0028; 0033; 0038
(2017/08/29)
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- Preparation of fluorine-containing methyl or aryl alkyl ketone method
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The invention discloses a method for preparing fluorine-containing methyl or alkylaryl ketones, belonging to an organic synthesis field. The method comprises two steps of: ester condensation: ester condensation reaction of an R1COOR2 compound represented by a formula A with a R2COOR2 compound represented by a formula B, is performed to form an R1COCH(R3)COOR2 intermediate represented by a formula C; and ester interchange: R1COCH(R3)COOR2 represented by the formula C is carried out ester interchange reaction with R2COOH under 100-110 DEG C and with catalysis of dilute H2SO4 or a cationic resin, and then decarboxylating to obtain R1COR2 fluorine-containing methyl or alkylaryl ketones represented by a formula D. The R1 group may be CF3-, CF2-, CF- or Ar-; the R2 group may be CH3-, Et- and n-Pr; and the R3 group may be CH3-, Et- and H-. Ester interchange in the invention avoids formation of HOR2 which has a nearly same boiling point with the compound represented by the formula D and is azeotropic with the compound represented by the formula D, enables the compound represented by the formula D to be purified without series rectification operation, and is suitable for large scale production. Simultaneously, ester interchange in the invention greatly raises cost. An ion exchange resin completes ester interchange in a waterless condition, which avoids a de-watering step, and simplifies technologies.
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Paragraph 0085
(2016/10/07)
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- PYRROLO AND PYRAZOLOPYRIMIDINES AS UBIQUITIN-SPECIFIC PROTEASE 7 INHIBITORS
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The invention relates to inhibitors of USP7 inhibitors useful in the treatment of cancers, neurodegenerative diseases, immunological disorders, inflammatory disorders, cardiovascular diseases, ischemic diseases, viral infections and diseases, and bacterial infections and diseases, having the Formula: where m, n, X1, X2, R1-R5, R5′ and R6 are described herein.
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Paragraph 2025; 2026
(2016/08/03)
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- Production technique of difluoroacetone
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The invention discloses a production technique of difluoroacetone. The technique adopts a batch process and comprises the following steps: 1. carrying out reaction on ethyl difluoroacetate, ethyl acetate and sodium ethylate at -5 to 10 DEG C to generate sodium ethyl difluoroacetoacetate, and heating to 20-50 DEG C to continue reacting for 16-24 hours under normal pressure; 2. rectifying the reaction product to separate out the generated ethanol, cooling to 5-10 DEG C, regulating the pH value to 2, slowly heating to carry out reaction under reflux, and carrying out reduced pressure distillation to obtain an intermediate product ethyl difluoroacetoacetate crude product; and 3. carrying out hydrolysis on the distillation product ethyl difluoroacetoacetate crude product at 20-100 DEG C under the catalytic action of an acid to obtain a difluoroacetone crude product, and carrying out purification rectification to obtain the difluoroacetone finished product.
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Paragraph 0012; 0014; 0015
(2017/06/23)
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- Novel process for preparing 4,4-difluoro-((2-dialkylamino) methylene)-3-oxobutanic acid alkyl ester
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The present invention relates to a novel method for preparing 4,4-difluoro-((2-dialkylamino) methylene)-3-oxobutanic acid alkyl ester which is represented by the following chemical formula ( I ) and useful as a manufacturing intermediate for fungicides such as isopyrazam, sedaxane, bixafen and the like. In the formula ( I ), R 1 and R 2 are each a C 1 to C 4 alkyl group, and R is a methyl group or an ethyl group. The compound of the formula ( I ) is produced by reacting dialkylformamide dialkyl acetal with a difluoro ketoester.
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Paragraph 0054; 0055; 0056
(2017/01/31)
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- PROCESS FOR PREPARING 1-ALKYL-3-FLUOROALKYL-1H-PYRAZOLE-4-CARBOXYLIC ACID CHLORIDES
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The present invention relates to a novel method for preparing 1-alkyl-3-fluoroalkyl-1H-pyrazole-4-carbonyl chlorides, a useful precursor for the preparation of fungicides, by means of reductive dehalogenation, starting from N-alkyl-3-haloalkyl-5-halopyrazolecarbaldehyde.
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Paragraph 0056; 0057
(2015/05/13)
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- PROCESS FOR PREPARING ALKYL 3-DIFLUOROMETHYL-1-METHYL-1H-PYRAZOLE-4-CARBOXYLATE AND ITS ANALOGS
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The disclosure provides a process for the preparation of alkyl 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylate and its analogs. The process includes a reaction workup method for Claisen condensation, wherein the enolate salt is acidified after removing remaining starting material and byproducts such as, ethanol and excessive ethyl acetate. The process also includes a method for completely drying alkyl difluoroacetoacetate and its analogs before use in the next step by reacting trialkyl orthoformate with the residual water. The process includes using Na2CO3 and /or K2CO3 to promote the ring-closure reaction to produce the alkyl 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylate. The process also includes effectively removing the regioisomer, alkyl 3-difluoromethyl-2-methyl-1H-pyrazole-4-caboxylate formed as a byproduct of the ring closure by a precipitation in a mixed solvent system and thereby eliminating the need for recrystallization of the final product.
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Paragraph 60-62
(2015/06/25)
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- IMPROVED PROCESS FOR PREPARING SUBSTITUTED CROTONIC ACIDS
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A process to prepare a compound of Formula (I) wherein R3, R4 and R5 are each selected independently from hydrogen, halogen, alkyl, alkenyl, alkynyl, alkoxyl, and wherein the alkyl, alkenyl, alkynyl, and alkoxyl may be optionally substituted with one or more halogen, alkyl, alkenyl, alkynyl, and alkoxyl.
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Page/Page column 18; 19
(2015/12/08)
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- A PROCESS FOR THE PREPARATION OF ALKYL 3-DIFLUOROMETHYL-1-METHYL-1H-PYRAZOLE-4-CARBOXYLATE AND ITS ANALOGS
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The disclosure provides a process for the preparation of alkyl 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylate and its analogs. The process includes a reaction workup method for Claisen condensation, wherein the enolate salt is acidified after removing remaining starting material and byproducts such as, ethanol and excessive ethyl acetate. The process also includes a method for completely drying alkyl difluoroacetoacetate and its analogs before use in the next step by reacting trialkyl orthoformate with the residual water. The process includes using Na2CO3 and/or K2CO3 to promote the ring-closure reaction to produce the alkyl 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylate. The process also includes effectively removing the regioisomer, alkyl 3-difluoromethyl-2-methyl-1H-pyrazole-4-carboxylate formed as a byproduct of the ring closure by a precipitation in a mixed solvent system and thereby eliminating the need for recrystallization of the final product.
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Paragraph 0060-0063
(2015/06/17)
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- SUBSTITUTED BICYCLIC COMPOUNDS AS mPGES-1 INHIBITORS
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The present disclosure is directed to compounds of formula (I), and pharmaceutically acceptable salts thereof, as mPGES-1 inhibitors. These compounds are inhibitors of the microsomal prostaglandin E synthase-1 (mPGES-1) enzyme and are therefore useful in the treatment of pain and/or inflammation from a variety of diseases or conditions, such as asthma, osteoarthritis, rheumatoid arthritis, acute or chronic pain and neurodegenerative diseases.
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Page/Page column 39
(2014/10/29)
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- PREPARATION OF ALKYL 3-DIFLUOROMETHYL-1-METHYL-1H-PYRAZOLE-4-CARBOXYLIC ACID ESTER
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The present disclosure provides a novel and economically advantageous process for preparation of compounds of Formula I, such as alkyl 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid ester. The process includes acidification of the sodium enolate of alkyl difluoroacetoacetate by carbonic acid generated in situ by reacting carbon dioxide with water. The disclosure also includes promoting the ring closure reaction in which alkyl 2-alkomethylene-4,4-difluoro-3-oxobutyrate is reacted with methylhydrazine in two phase system with a weak base such as Na2CO3 or K2CO3.
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Paragraph 0055; 0057
(2014/08/19)
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- BICYCLIC COMPOUNDS AS mPGES-1 INHIBITORS
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The present disclosure is directed to compounds of formula (I), and pharmaceutically acceptable salts thereof, as mPGES-1 inhibitors. These compounds are inhibitors of the microsomal prostaglandin E synthase-1 (mPGES-1) enzyme and are therefore useful in the treatment of pain and/or inflammation from a variety of diseases or conditions, such as asthma, osteoarthritis, rheumatoid arthritis, acute or chronic pain and neurodegenerative diseases.
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Paragraph 0559
(2013/08/28)
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- Novel Imidazole Derivatives Useful for the Treatment of Arthritis
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The present invention provides compounds of the formula below: where A, X and R1-R6 are as described herein, a pharmaceutical salt thereof, and a pharmaceutical composition containing this compound; methods of treating pain associated with osteoarthritis using one of the compounds or a pharmaceutically acceptable salt thereof, and processes for preparing the compounds.
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Page/Page column 4; 5
(2012/12/13)
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- PROCESS FOR THE PREPARATION OF ENOLATE SALTS OF 4-FLUORO-2-HYDROXYMETHYLENE-3-OXO-BUTYRATES
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Enolate salts of 4-fluoro-2-hydroxymethylene-3-oxobutyrates of formula wherein R1 is C1-10 alkyl, R2 and R3 are independently hydrogen or fluorine, M is an alkali or alkaline earth metal, and n is 1 or 2, are prepared from enolate salts of the corresponding 4-fluoro-3-oxobutyrates and carbon monoxide. The enolate salts of formula I can be alkylated or acylated to obtain the corresponding enol ethers and esters. The 4-fluoro-3-oxobutyrate starting material can be prepared from 1,1-difluoroethyl methyl ethers by SbF5-catalyzed fluoromethane elimination followed by halogen exchange with lithium chloride, reacting the thus obtained fluoroacetyl chloride with ketene and quenching with the appropriate alcohol R1-OH.
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Page/Page column 12-13
(2012/02/02)
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- Preparing 5-fluoro-1-alkyl-3-fluoroalkyl-1H-pyrazole-4-carbonyl chlorides
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The present invention relates to a novel process for preparing 5-fluoro-1-alkyl-3-fluoroalkyl-1H-pyrazole-4-carbonyl chlorides, a useful intermediate in the manufacture of fungicides.
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Page/Page column 4
(2011/09/16)
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- Synthesis of new fluorine-containing pyrazolo[3,4-b]pyridinones as promising drug precursors
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Methods for the synthesis of 4-R-6,7-dihydro-1H-pyrazolo[3,4-b]pyridin-6- ones (R = CF2SAr and 4-CFHSAr) were developed. The derivatives with R = CF2SAr were obtained by both heterocyclization of 1-substituted 5-aminopyrazoles with ethyl 4,4-difluoro-3-oxo-4-phenylsulfanylbutanoate and replacement of the Br atom in 4-bromodifluoromethyl-6,7-dihydro-1H-pyrazolo[3,4- b]pyridin-6-ones by sodium arenethiolates. The fragment 4-CF-HSAr was introduced by replacement of the Cl atom in 4-chlorofluoromethyl-6,7-dihydro-1H- pyrazolo[3,4-b]pyridin-6-ones by sodium arenethiolates. Oxidation of 4-CF 2SPh-6,7-dihydro-1H-pyrazolo[3,4-b]pyridin-6-ones gave the corresponding sulfoxides; their structures were confirmed by X-ray diffraction data.
- Golubev,Starostin,Chunikhin,Peregudov,Rodygin,Rubtsova,Slepukhin,Kuchin,Chkanikov
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experimental part
p. 733 - 745
(2012/02/05)
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- METHOD FOR PRODUCING DIHALO ACETOACETIC ALKYL ESTERS
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The invention relates to a process for preparing alkyl dihaloacetoacetates of the formula (I) by reacting α,α-dihaloamines of the formula (III) with acetic esters of the formula (II) in the presence of bases.
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Page/Page column 3
(2010/06/11)
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- Process for preparing alkyl 2-alkoxymethylene-4,4-difluoro-3-oxobutyrates
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A process for preparing alkyl 2-alkoxymethylene-4,4-difluoro-3-oxobutyrates (VI) where R is methyl or ethyl, from crude reaction mixtures of alkyl 4,4-difluoroacetoacetates (I) by a) reacting alkyl acetate (II), RO M alkoxide (III), where M is a sodium or potassium ion, and alkyl difluoroacetate (IV), without additional solvent to form an enolate (V), b) releasing the corresponding alkyl 4,4-difluoroacetoacetate (I) from the enolate (V) by means of acid, c) removing the salt formed from cation M and acid anion as a solid and d) converting (I), without isolation from the crude reaction mixture, to the alkyl 2-alkoxymethylene-4,4-difluoro-3-oxobutyrate (VI), and the use of (VI) for preparing 1-methyl-3-difluoromethyl-pyrazol-3-ylcarboxyates (VII).
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Page/Page column 7
(2009/10/21)
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- PROCESS FOR THE PREPARATION OF ESTERS OF 4-FLUOROSUBSTITUTED 3-OXO-ALCANOIC ACIDS
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Esters of 4-fluorosubstituted 3-oxo-alcanoic acids can be prepared by addition reaction of ketene with the respective acid chloride, subsequent esterification and hydrodechlorination. Preferred reaction products are esters of 4,4- difluoro-3-oxo-butanoic acid.
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Page/Page column 4
(2009/04/25)
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- FUNGICIDAL COMPOSITIONS
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A composition suitable for control of diseases caused by phytopathogens comprising (A) a compound of Formula (I) or a compound of Formula (II) wherein R1b is difluoromethyl or trifluoromethyl and R2bis alkyl, alkoxyalkyl or haloalkyl, or tautomers of such compounds; and (B) a compound selected from compounds known for their fungicidal activity.
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Page/Page column 6-7
(2008/06/13)
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- Studies on a three-step preparation of β-fluoroalkyl acrylates from fluoroacetic esters
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β-Fluoroalkyl-acrylic esters are valuable building blocks for the synthesis of organofluorine compounds. Although the preparation of several β-fluoroalkyl-acrylates is known, a general and straightforward lab-scale methodology for the preparation of multigram amounts of these compounds from fluoroacetic esters is not available, and the related chemistry has not been investigated in detail. We now describe an optimized three-step protocol relying on: (1) Claisen-type condensation of fluoroacetic esters with ethyl acetate, using LDA as base; (2) reduction of the resulting γ-fluoro-β-keto esters by NaBH4, using toluene or benzene as solvents; (3) P2O5-promoted dehydration of the intermediate γ-fluoro-β-hydroxy esters. The methodology affords preparatively useful yields of the target compounds incorporating only fluorine atoms (CF3, CHF2, C2F5), whereas the γ-halodifluoromethyl (CClF2, CBrF2, CIF2) acrylates could not be obtained in analytically pure form from the dehydration step.
- Jagodzinska, Monika,Huguenot, Florent,Zanda, Matteo
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p. 2042 - 2046
(2007/10/03)
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- PROCESS FOR THE PREPARATION OF 4,4-DIFLUORO-3-OXOBUTANOIC ACID ESTERS
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The present invention relates to a process for the preparation of a compound of the formula (I), wherein R is C1-12 alkyl, by the contact of a compound of the general formula (II) , wherein R1 and R2 are each, independently, C1-12 alkyl; or R1 and R2 join together with the nitrogen atom to which they are attached to form an alicyclic amine ring containing 4 to 7 carbon atoms or a morpholine ring, with an acetic acid ester of the general formula (III) CH3COOR, wherein R is as defined under formula (I), in the presence of a base.
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Page/Page column 7
(2010/02/15)
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- 1-METHYL-3-DIFLUOROMETHYL-PYRAZOL-4-CARBONIC ACID-(ORTHO-PHENYL)-ANILIDES, AND USE THEREOF AS A FUNGICIDE
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The invention relates to 1-methyl-3-difluoromethyl-pyrazol-4-carbonic acid-(ortho-phenyl)-anilides of formula (I), wherein the substituents have the following meaning: R1 and R2 independently represent halogen, C1-C6 alkyl, C1-C6 alkyl halide, cyano, nitro, methoxy, trifluoromethoxy, or difluoromethoxy.
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Page/Page column 20-21
(2008/06/13)
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- METHOD FOR PRODUCING DIFLUORO-ACETYL-ACETIC ACID ALKYLESTERS
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The invention relates to a three-stage method for producing 4, 4-difluoro-acetyl-acetic acid alkylesters. In a first stage, a reaction of 4-chloro-4, 4-difluoro-acetyl-acetic acid alkylesters with trialkyl-phosphites of formula (III) P(OR1)3 is carried out, wherein R1 is C1-C4 alkyl, the R1 groups can be identical or different for producing alkyl-phosphonic acid esters of formula (IV) which react with amine of formula (V) during a second stage, wherein R2 and R3 are hydrogen or C1-C4 alkyl independent of each other, or jointly CH2-CH2-O-CH2-CH2- for forming enamines of formula (VI), wherein R2 and R3 have already mentioned significance, said enamines being hydrolysed in the presence of an acid during a third stage.
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- Regiocontrolled synthesis of 3-substituted-6-trifluoromethyl-4(3H)-pyrimidinones
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Direct reaction of a variety of N-monosubstituted benzamidines with 4,4,4-trifluoroacetoacetate esters substituted at the 2-position with methyl, ethyl or methoxy afforded moderate to good yields of herbicidal 3-substituted-6-trifluoromethyl-4(3H)-pyrimidinones. Lower yields were obtained with the corresponding 4,4-difluoroacetoacetate esters and the reaction failed with nonfluorinated β-ketoesters. In addition to benzamidines, 3- and 4-pyridylcarboxamidines reacted successfully. The reaction tolerated propyl, allyl, propargyl and phenyl substituents on the amidine nitrogen.
- Tice,Bryman
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p. 2689 - 2700
(2007/10/03)
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- Reformatsky-type aldol reactions of 4-bromo-4,4-difluoroacetoacetate with aldehydes and ketones
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In the presence of zinc and a catalytic amount of copper(I) chloride, 4-bromo-4,4-difluoroacetoacetate 4 reacted with a series of aromatic aldehydes and aryl alkyl ketones to give the corresponding δ-hydroxyl-γ,γ-difluoro-β-ketoesters 6 in good to excellent yields under mild conditions.
- Wang, Yanli,Zhu, Shizheng
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p. 5741 - 5744
(2007/10/03)
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- A microbially-based approach for the synthesis of chiral secondary alcohols bearing the difluoromethyl or chlorodifluoromethyl group
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A synthetic approach to both enantiomers of the secondary alcohols , involving the stereoselective hydrolysis of ester derivatives, is described.The absolute configurations of these difluoromethylated or chlorodifluoromethylated molecules were determined.
- Kitazume, Tomoya,Asai, Masatomo,Tsukamoto, Takashi,Yamazaki, Takashi
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p. 271 - 284
(2007/10/02)
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