- PYRIMIDINEDIONE DERIVATIVES
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The present invention covers pyrimidinedione derivatives of general formula (I) : (I), in which R1, R2, R4, R5 and X are as defined herein, methods of preparing said compounds, intermediate compounds useful for
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Page/Page column 72
(2021/04/10)
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- Toward Continuous-Flow Synthesis of Biologically Interesting Pyrazole Derivatives
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A two-step continuous-flow synthesis of substituted pyrazole derivatives has been developed via the formation of vinylidene keto esters as key intermediates. Heterogeneous Ni2+-montmorillonite was found to be an efficient catalyst for orthoester condensation of 1,3-dicarbonyls under flow conditions. The intermediate reacted with methylhydrazine to afford pyrazole derivatives, for which suitable selection of a solvent played a key role in achieving high yields and excellent regioselectivities of the desired products. An application of this protocol has been demonstrated by the synthesis of a key intermediate for biologically active pyrazoles such as Bixafen. (Figure presented.).
- Das, Amrita,Ishitani, Haruro,Kobayashi, Shū
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supporting information
p. 5127 - 5132
(2019/11/13)
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- An atom-efficient route to ethyl 3-(difluoromethyl)-1-methyl-1 H-pyrazole-4-carboxylate (DFMMP)-A key building block for a novel fungicide family
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A growing number of fluorine-containing active ingredients in the pharmaceutical and agrochemical industries inevitably raises the demand for new fluorinated building blocks. Their availability is mainly constricted by suitable chemistry and available bulk fluorine containing starting materials. Because of the high cost impact especially in the agrochemical industry, the choice of a synthetic route is heavily driven by economic aspects; thus, the environmental profile often is handled as a "secondary factor" or finally falls aside. DFMMP is a key building block for a fast growing new fungicide family, like Syngenta's Sedaxane, and BASF's Fluxapyroxad and Bayer's Bixafen currently made by environmetally less friendly routes. Herein we present a cost-competitive and green route, developed at Solvay laboratories, displaying significantly lower environmental impact.
- Jaunzems, Janis,Braun, Max
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p. 1055 - 1059
(2014/10/15)
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- IMPROVED PROCESS FOR THE PREPARATION OF ESTERS OF 1-H-PYRAZOLE-4-CARBOXYLIC ACIDS
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Process for the manufacture of an ester of a 1-H-pyrazole-4-carboxylic acid of formula (I) wherein - R1 is H or an organic residue - R2 is H or an organic residue - R3 is H, an alkyl group having from 1 to 12 carbon atoms, an halogenated alkyl group having from 1 to 12 carbon atoms, an aralkyl group, an aryl group, a halogen. which comprises reacting a compound of formula (II): wherein R4 is C1-C8-alkyl, C3-C8-cycloalkyl, C2-C8-alkenyl, benzyl or phenyl,R1 and R3, are as defined above with a hydrazine of formula (III): R2NHNH2 (III) wherein R2 is as defined above, in the presence of an organic solvent comprising at least one halogen.
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Page/Page column 14
(2012/03/26)
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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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- COMPOSITIONS OF ESTERS OF FLUOROSUBSTITUTED ALCANOIC ACIDS
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Composition of esters of fluorosubstituted alcanoic acids, comprising or consisting essentially of a compound of a formula selected from the group consisting of: RCFCIC(OAc)=CHC(O)OR1 (II); RCFHC(O)CH2C(O)OR1 (IV); RCFHC(OAc)=CHC(O)OR1 (V); and RCFHCH(OAc)CH2C(O)OR1 (VI); or of compounds of formula (I) RCFCIC(O)CH2C(O)OR1 and of formula (II); of compounds of formulae (IV) and (V); or of compounds of formulae (IV) and (VI); wherein R is C2F5, CF3 or F and R1 is an alkyl group with from 1 to 4 carbon atoms, an alkyl group with from 1 to 4 carbon atoms substituted by 1 or more fluorine atoms. A process for the reduction of the compound of formula (I) and/or formula (II), and compositions resulting from such reduction. A process for the separation of the compound of formula (I) from the compound of formula (II) comprising subjecting a composition comprising such compounds to a distillation operation.
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Page/Page column 6-7
(2010/09/17)
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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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- 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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- 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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- 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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