Fluorinated carboxylic acids

For most cases, common fluoroacyl derivatives are sufficiently reactive and selective Thus conversion of perfluoroglutaric dichloride to a monomethyl ester by methanol proceeds smoothly under the appropriate reaction conditions [17] (equation 9) Perfluorosuccinic acid monoester fluoride, on the other hand, is prepared most conveniently from perfluorobutyrolacetone (equation 10) Owing to the strong acidity of a fluorinated carboxylic acids, Fischer esten-ficaiton with most aliphatic alcohols proceeds autocatalytically [79 20]... 

Murray-Rust, P., W. C. Stallings, C. T. Monti, R. K. Preston, and J. P. Glusker. 1983. Intermolecular Interactions of the C-F Bond The Crystallographic Environment of Fluorinated Carboxylic Acids and Related Structures. J. Am. Chem. Soc. 105, 3206. 

By reacting first with ethyl bromoacetate, a fluorinated carboxylic acid (III) resulted, which was then converted into the acid chloride (IV) and subsequently reacted with hydroxyethyl methacrylate or hydroxypropyl methacrylate giving rise to the monomers V, as shown in Figure 1.2. All these monomers are clear, colorless liquids, and were characterized by NMR and FTIR spectra and elemental analyses. 

V,A -Diethyl-l.l,2,3,3,3-hexafluoropropanamine (10, Ishikawa reagent) is a mild fluorinating agent which can convert primary, secondary and tertiary alcohols (which do not easily form carbanions) to their corresponding fluorides (see Table 3). It can also readily fluorinate carboxylic acids to their corresponding acid fluorides. 

Diethyl(trifluoromethyl)amine (19) and [difluoro(phenyl)methyl](dimethyl)amine (21) are mild reagents which can fluorinate alcohols to their corresponding fluorides. They can also fluorinate carboxylic acids to their corresponding fluorides however, good yields are only obtained when the product is sufficiently volatile to be distilled off during the course of the reaction. 

Perfluoropropene (1) can be directly oxidized to perfluoro-1,2-epoxypropane (2) by a variety of oxidizing reagents, e.g. oxygen, hydrogen peroxide.50 s2 Pcrfluoro-1,2-epoxypropane (2) can fluorinate carboxylic acids to their corresponding acid fluorides in the presence of tertiary amines.52 55... 

Potassium permanganate oxidation of a vinyl group to a carboxyl group can be used to prepare fluorinated carboxylic acids with aliphatic (. < ] (equauon 30) or alicyclic [39] (equation 31) skeletons... 

Formate ion shows high nucleophilicity towards fluorinated alkenes and provides a route to fluorinated carboxylic acids [103] (Scheme 45). 

Addition of halogen fluorosulfates XOS02F (X=C1, Br, I) to fluoroolefins is considered an electrophilic reaction [8]. However, the question of whether this process is concerted or the reaction proceeds via an independent carbocationic intermediate (Eqs. 2 and 3) is still open. Formation of carboxylic acid esters as byproducts in the reaction of HFP with C10S02F, which was carried out in trifluoroacetic or heptafluorobutyric acids as solvents, could not be a solid proof of conjugate addition, since formation of esters may be a result of addition of C10C(0)Rf to olefin. These materials are known to be formed in the reaction of ClOS02F with fluorinated carboxylic acids, even at low temperature [99]. 

Murray-Rust P, Stallings WC, Monti CT, Preston RK, Glusker JP (1983) Intermolecular interactions of the C-F bond the crystallographic environment of fluorinated carboxylic acids and related structures. J Am Chem Soc 105 3206- 3214... 

Synthesis of Fluorinated Carboxylic Acids, Esters, Amides, Ketones, and Alcohols through Halogen Exchange... 

Under basic conditions fluorinated carboxylic acids react with alkyl iodides " or bromides. Silver oxide seems to be the base of choice for the synthesis of difluoro(nuorosulfonyl)acetic esters 6 (from 5). ... 

Finally, fluorinated carboxylic acids react with epoxides (trimethylaluminum-catalyzed).- and conveniently with diazo conipounds. Cycloaddition is observed with diazo-methane. Reaction of compound 7 with trifluoroacetic acid alone is relatively slow (Freon 113, reflux, 12 h, for completion of reaction) however, catalytic amounts of copper(ll) perchlorate increase the rate of formation of ester 8 (rt, 5 min). ... 

The oxidation of fluoro compounds with potassium permanganate in an alkaline medium is of long standing. This reaction is a convenient method for the preparation of a-fluorinated carboxylic acids, particularly for the production of fluorochloroalkanecarboxylic and per-fluorinated acids. Carboxylic acids which have an a-hydrogen and -fluorine cannot be produced in this way because they eliminate hydrogen fluoride under the influence of alkali. ... 

The pyrolytic decomposition of the sodium salts of various fluorinated carboxylic acids to give isomeric unsaturated compounds has also been reported. The products were identified as alkenes with the C = C bond inside the carbon chain, mainly alk-2-enes. This isomerization may be catalyzed by the coal-like products formed during the pyrolytic decarboxylation of the salts, but the metal fluoride formed in the reaction may also be responsible for the isomerization. When potassium perfluoro(5-chloropentanoate) is heated in a rocking autoclave at 300 C for 2 hours, perfluorobut-2-ene (2b) is isolated in 82% yield.This is only possible by migration of the double bond away from the terminal position after carbon dioxide elimination and halogen exchange to form potassium chloride. ... 

The discussion of acylation reactions in this chapter is focused on fluorinated carboxylic acid derivatives and their use to build up new fluorine-containing molecules of a general preparative interest Fifteen years ago, fluonnated carboxylic acids and their derivatives were used mainly for technical applications [/] Since then, an ever growing interest for selectively fluorinated molecules for biological applications [2, 3, 4, 5] has challenged many chemists to use bulk chemicals such as tnfluoroacetic acid and chlorodifluoroacetic acid as starting materials for the solution of the inherent synthetic problems [6, 7, 3, 9]... 

Acylation of various oxygen functions by use of common and commercially available fluorinated carboxylic acid denvatives such as trifluoroacetic anhydride or the corresponding acyl halides have already been discussed sufficiently in the first edition [10] Therefore only exceptional observations will be described in this section In the past 15 years, many denvatizations of various nonfluormated oxygen compounds by fluoroacylation were made for analytical purposes. Thus Mosher s acid chlorides for example became ready-to-use reagents for the determination of the enantiomeric purity of alcohols and amines by NMR or gas-liquid chromatographic (GLC) techniques [//] (equation 1)... 

Thus, for example, in the presence of some highly fluorinated carboxylic acids and their salts, the value yc for polyethylene is decreased from its usual value of almost 31 mN/m to about 20 mN/m (Bernett, 1959) by adsorption of the fluorinated surfactants onto the polyethylene surface, with the result that solutions of these surfactants having surface tensions less than the normal yc for polyethylene do not spread on it. The requirement that the surface tension of the wetting liquid be reduced by the surfactant to some critical value characteristic of the substrate is thus a necessary, but not sufficient, condition for complete spreading wetting. A surfactant solution whose surface tension is above the critical tension for the substrate does not produce complete wetting, but a solution whose surface tension is below the critical tension for the substrate may or may not produce complete wetting (Schwarz, 1964). 

After intensive research and development work, Asahi Chemical filed the basic patents of fluorinated carboxylic acid membrane and carboxylic and sulfonic acid membrane and the related electrolysis processes in 1974 (1 - 8). 

Fluorinated carboxylic acids Alkanoic acid fluorides 3M Dai Nippon... 

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