- ANALYSE STRUCTURALE DES HALOGENOPROPANONES
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Methylene bending mode analysis (1400-1500 cm-1 region) and dipole moment determinations are carried out in the dissolved state (solvent CCl4) for fluoropropanone (I) and 1,3-difluoropropanone (II).The results are consistent with the existence of two conformations, "cis" and "trans", for (I) and one conformation "cis-trans" for (II).Theoretical evaluations of conformer stabilities by the PCILO method and Onsager formalism are in reasonable agreement with these experimental results.
- Maury, Catherine,Bonniol, Alain,Lere-Porte, Jean-Pierre,Petrissans, Jean
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- REACTIVE EXTRACTION OF WATER
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Described herein are methods and compounds for extracting water from an aqueous solution. For example, some embodiments include method for extracting water from an aqueous solution, comprising contacting the aqueous solution with a compound comprising one or more carbonyl moieties having an equilibrium constant for a hydration of the carbonyl moiety of at least about 0.5; separating a composition comprising the hydrated compound from the aqueous solution; and reacting the hydrated compound to obtain water.
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Paragraph 0077; 0078
(2020/04/09)
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- Synthesis of 2-Fluoroacetoacetic Acid and 4-Fluoro-3-hydroxybutyric Acid
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The butyric acid scaffold is the base structure of several human metabolites that serve diverse and prominent biochemical roles including as oxidative sources of cellular energy and as substrates for biosynthesis. Derivatization of metabolites through incorporation of fluorine often alters bioactivity and can facilitate detection and analysis by nuclear magnetic resonance or positron emission tomography depending upon the fluorine isotope employed. We describe the synthesis of two new fluorinated butyric acids (and three related esters) that are derivatives of the metabolites acetoacetic acid and 3-hydroxybutyric acid. 4-Fluoro-3-hydroxybutyric acid is prepared from epoxy ester precursors via ring opening by triethylamine trihydrofluoride. 2-Fluoroacetoacetic acid is prepared by electrophilic fluorination of an acid-labile β-keto ester. The gradual pH-dependent decarboxylation of 2-fluoroacetoacetic acid is investigated by 19 F NMR spectroscopy.
- Mattingly, Stephanie J.,Wuest, Frank,Schirrmacher, Ralf
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p. 2351 - 2358
(2019/05/24)
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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 0095
(2016/10/07)
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- Unusual reversal of regioselectivity in antibody-mediated aldol additions with unsymmetrical methyl ketones
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A catalytic regio- and enantioselective aldol reaction of various unsymmetrical methyl ketones with para-nitrobenzaldehyde has been developed using aldolase antibodies as the catalysts. It has been found that the sense and level of regioselectivity for the reactions catalysed by antibody 38C2 and 33F12 are highly dependent on the structure of both the donor and the acceptor but in contrast, antibodies 84G3 and 93F3 catalyse the exclusive formation of the linear regioisomer independent of the structure of the reactants examined. The level of enantiocontrol is very high for most reactions. Both linear aldol enantiomers could be accessed through aldol or retro-aldol reactions using the same antibody. Theoretical studies on regioisomeric α- and β-heteroatom substituted enamines derived from unsymmetrical ketones suggest that most of the linear aldol products formed in the presence of antibodies 84G3 and 93F3 must be formed from intermediate enamines which are not the thermodynamically most favourable.
- Maggiotti,Bahmanyar,Reiter,Resmini,Houk,Gouverneur
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p. 619 - 632
(2007/10/03)
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- Process for producing 1,1,1-trifluoroacetone
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A process for producing 1,1,1-trifluoroacetone includes the step of conducting a hydrogenolysis of a halogenated trifluoroacetone, which is represented by the general formula (1), by a hydrogen gas in the presence of a catalyst containing a transition metal, where X represents a chlorine, bromine or iodine, and n represents an integer from 1 to 3. It is possible to obtain 1,1,1-trifluoroacetone with a high yield by using the special catalyst.
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- Studies on the reaction of D-glucal and its derivatives with 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]Octane salts
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The reaction of D-glucal and its derivatives with the electrophilic N-F-fluorination reagents F-TEDA tetrafluoroborate and triflate was studied by means of 19F NMR spectroscopy. In all cases mixtures of 2-deoxy-2-fluoro-D-gluco- and -D-mannopyranose derivatives were formed, the ratio of which was dependent on the nature of the O-protecting groups. Concerning the products arising from the direct addition of reagents across the double bond, the D-gluco-configured compounds (13-20) generally showed higher hydrolysis rates than their D-manno-counterparts (21-28). Product separation was only achieved when single anomers (e.g., 2,4-dinitrophenyl glycosides 29e/37e and disaccharidic fluorides 35d/43d) or per-O-acetates (e.g. 29f/37f) were formed.
- Ortner,Albert,Weber,Dax
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p. 297 - 316
(2007/10/03)
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- Synthesis, Regioselective Deprotonation, and Stereoselective Alkylation of Fluoro Ketimines
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Fluoroacetone imines of cyclohexylamine, valinol O-methyl ether, and phenylalaninol O-methyl ether and 2-fluorocyclohexanone imines of cyclohexylamine and phenylalaninol O-methyl ether were prepared.The temperature-dependent, regioselective deprotonation of these imines was employed in highly regioselective alkylation reactions.The deprotonation of fluoroacetone cyclohexylimine on the carbon bearing fluorine yielded only a single stereoisomer as determined by low temperature 19F NMR.In contrast, deprotonation of fluoroacetone O-benzyloximes was not regiospecific under any of the conditions examined.
- Welch, John T.,Seper, Karl W.
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p. 2991 - 2999
(2007/10/02)
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- UEBER TRISHYDROFLUORIDE TERTIAERER AMINE UND IHREN EINSATZ ALS FLUORIERUNGSMITTEL
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Tertiary amine trishydrofluorides are stable complexes which are distillable in vacuo.They can be handled without hazard and do not corrode borosilicate glass.They are convenient agents therfore, in nucleophilic replacement reactions of chlorine or bromine atoms by fluorine forming homogeneous reaction mixtures often leading to higher yield under very mild conditions.Examples are given for the preparation of fluoroacetone, cyanuric fluoride, difluorophosgene, oxalyl fluoride and sulfur tetrafluoride.
- Franz, R.
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p. 423 - 434
(2007/10/02)
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- The Reversible Hydration of Carbonyl Compounds in Aqueous Solution. Part I, The Keto/Gem-diol Equilibrium
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The equilibrium constants of hydration (given in parenthesis) have been determined for the aliphatic aldehydes acetaldehyde (1.2), propionaldehyde (1.24), butyraldehyde (0.58), pentanal (0.34), and hexanal (0.41), for the halogenated acetones chloraceton (0.091), fluoroacetone (0.167), and 1,1,1-trifluoroacetone (35), and for the 1,2-dicarbonyl compounds 2,3-butanedione (2.1) and 2,3-pentanedione (1.7).Comparing the constants shows, that the equilibrium of hydration of carbonyl compounds is determined mainly by the inductive effects of the substituents.
- Buschmann, Hans-Juergen,Fueldner, Hans-Hagen,Knoche, Wilhelm
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