383-56-2Relevant articles and documents
Preparation of fluorine-containing methyl or aryl alkyl ketone method
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Paragraph 0074, (2016/10/07)
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.
Absolute rate constants for the addition of the 2- (methoxycarbonyl)propan-2-yl and the 3,3,3-trifluoracetonyl radicals to alkenes in solution
Zytowski, Torsten,Knuehl, Bernhard,Fischer, Hanns
, p. 658 - 675 (2007/10/03)
Absolute rate constants and some of their Arrhenius parameters were obtained by time-resolved electron spin resonance (ESR) spectroscopy for the addition of the 2-(alkoxycarbonyl)propan-2-yl and 3,3,3-trifluoroacetonyl (= 3,3,3-trifluoro-2-oxopropyl) radicals to a variety of mono- and 1,1- disubstituted alkenes. Their analysis shows that the addition of 2- (alkoxycarbonyl)propan-2-yl is mainly governed by the exothermicity of the reaction with slight modifications by nucleophilic and electrophilic effects giving rise to an overall ambiphilic behavior. In contrast, large electrophilic polar effects dominate the addition of the 3,3,3- trifluoroacetonyl (= 3,3,3-trifluoro-2-oxopropan-2-yl) radical, as it is expected from its large electron affinity. For both radicals, the activation energies are well-predicted by analytic equations for the enthalpic and polar terms. A comparison of the rate data of 2-(alkoxycarbonyl)propan-2-yl with the homo- and copolymerization rate constants of the propagating radical of methyl methacrylate shows that the additions of these structurally related low- and high-molecular-weight radicals to alkenes are governed by very, similar effects.
Study for the determination of the absolute configuration of fluoromethylated secondary alcohols by the modified Mosher method
Xiao, Ling,Yamazaki, Takashi,Kitazume, Tomoya,Yonezawa, Tetsuo,Sakamoto, Yoshitake,Nogawa, Kouji
, p. 19 - 23 (2007/10/03)
Application of the modified Mosher method using high-field FT 1H NMR to the 2-methoxy-2-phenyl-2-trifluoromethyl acetic acid (MTPA) derivatives of fluorinated secondary alcohols indicates that this method may be generally used to determine the absolute configurations of these materials.
Reactions of Trifluoromethyl Bromide and Related Halides: Part 9. Comparison between Additions to Carbonyl Compounds, Enamines, and Sulphur Dioxide in the Presence of Zinc
Tordeux, Marc,Francese, Catherine,Wakselman, Claude
, p. 1951 - 1957 (2007/10/02)
A Barbier procedure, under moderate pressure, was used for the trifluoromethylation of various carbonyl compounds, starting from trifluoromethyl bromide and zinc in pyridine.Trifluoromethyl methanols were obtained from aldehydes and trifluoromethyl ketones from activated esters.Ethyl benzoate, or acetone, induced the formation of the solvated trifluoromethylzinc derivatives which did not react with carbonyl cpompounds.Consequently, the Barbier condensation in that case was considered to involve nascent organometallics reacting near the zinc surface.The reaction with sulphur dioxide, leading to trifluoromethanesulphinate, showed striking differences from that of carbonyl compounds.It was shown that the main pathway occcured in solution.This condensation was interpreted by the initial formation of sulphur dioxide radical anion, which reacts with trifluoromethyl bromide by a single-electron-transfer process.Attempts to condense iminium salts failed when a hydrogen atom was lacking in the α position.When the iminium ion can be transformed in situ to an enamine, a reaction occured, leading to α-trifluoromethyl ketones.This condensation was interpreted by a chain mechanism involving trifluoromethyl radicals.
Process for perfluoroalkylation of acid anhydrides
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, (2008/06/13)
A process for the preparation of perfluoroalkylated ketones and/or perfluoroalkylated alcohols, comprising the step of contacting a perfluoroalkyl iodide or perfluoroalkyl bromide with an acid anhydride, in the presence of a metal chosen from zinc and cadmium.
REACTIONS OF BROMORTRIFLUOROMETHANE WITH ACID DERIVATIVES IN THE PRESENCE OF ZINC.
Francese, C.,Tordeux, M.,Wakselman, C.
, p. 1029 - 1030 (2007/10/02)
Reaction of zinc with bromotrifluoromethane in pyridine gives poorly reactive trifluoromethyl zinc derivatives in the presence of ethyl benzoate whereas the Barbier condensation occurs with activated esters, like ethyl trifluoroacetate or ethyl oxalate, and cyclic anhydrides.
Deamination Reactions, 43 - The Effect of Trifluoromethyl Groups on the Reactivity of Aliphatic Diazonium Ions and Carbocations
Gassen, Karl-Rudolf,Kirmse, Wolfgang
, p. 2233 - 2248 (2007/10/02)
Various trifluoroalkanamines (9, 26, 35, 38, 45, 56, and 67) have been prepared and diazotized (water, pH 3.5) to probe the effect of trifluoromethyl groups on the reactivity of aliphatic diazonium ions.The product distributions reveal that α-CF3 groups enhance inverting displacement and enforce rearrangement (hydride shifts) separating the positive charge from CF3.Migrations of the positive charge from the β- to the γ-position are less strongly promoted than those from α to β.Enhancement factors of ca. 15 (α -> β) and 4 (β -> γ) may be derived by comparison with analogous alkanediazonium ions.The positive charge does not migrate in the reverse direction (β -> α) except for minor amounts of a pinacolic rearrangement (68 -> 7).A migration of the positive charge from γ to β has been detected with 36 but a tenfold decrease as compared to the analogous butanediazonium ion 37 is indicated.All observations are reasonably explained in terms of the relative stabilities of the intermediate trifluoroalkyl cations.
DIASTEREOSELECTIVE REDUCTION OF PERFLUOROALKYLATED α,β-UNSATURATED KETONES WITH BAKER'S YEAST
Kitazume, Tomoya,Ishikawa, Nobuo
, p. 587 - 590 (2007/10/02)
The differentiation of a fluorinated group in the molecule with active fermenting yeast and the double asymmetric induction in some perfluoroalkylated α,β-unsaturated ketones are described.