Carboxylates fluorinated compounds

Production and Uses of Aliphatic Compounds II Ether, Epoxide and Pnlyeiher, Carboxylic Acids and Their Denvatives, Sulfonic Acids, Toxicological Data of Aliphatic Fluorine Compounds (Ger) Liebig, H, Ulm, K Chem Ztg 100 3-14 270... 

Fig. 2.9.48. (a) APCI-FIA-MS-MS(+) (CID) product ion mass spectrum of selected [M + NH4]+ parent ion (m/z 528) offluorinated non-ionic surfactant metabolite identified as PEG-chain carboxylated fluorine containing non-ionic surfactant homologue (general formula C F2n+i-(CH2-CH2-0)m-CH2-C00H) fragmentation behaviour under CID(+) presented in the inset (b) APCI-FIA-MS-MS(—) (CID(—)) product ion mass spectrum of [M - H] parent ion (m/z 465) of compound as in (a) [37]. 

Detailed analyses of partially fluorinated compounds from the ECF of amines, and relatively simple sulphonic acid derivatives have been performed with interesting and illuminating results but do these observations translate into other complex systems, e. g., long chain carboxylic acid derivatives The experiments have yet to be done. 

Oxidation with ozone is a common method for the preparation of fluorinated compounds. Cyclic or linear alkenes can be treated with ozone and, depending on the workup of the reaction mixture, aldehydes, ketones or carboxylic acids are produced. This is illustrated by the ozonoly-sis of. l,.3,4.4-tetrafluorocyclohexene. Oxidative workup gives, depending on the oxidizing agent, formylpentanoic acid 3 or the diaeid 4 with reductive workup the dialdehyde 2 is obtained. If the alkene is substituted by an alkyl group, the product is a ketone. 

The dominant source of fluorine compounds as precursors for systems that will take part in these cyclizations are the fluorocarbon carboxylic adds. Many of these compounds are available through electrochemical fluorination processes (Eq. 40),157 which are carried out on an industrial scale. These can then be converted to standard derivatives which are employed in the various ways described in this section. 

The dominant source of fluorine compounds as precursors for systems that will take part in these cyclizations are the fluorocarbon carboxylic acids. Many of these compounds are available through electrochemical fluorination... 

Section 2.2 mainly reviews the papers on novel fluorinated organic solvents, which include fluorinated lactones, fluorinated linear carboxylates, fluorinated cyclic carbonates, fluorinated linear carbonates, fluorinated monoethers, fluorinated diethers, and others. The physicochemical properties of typical fluorinated compounds are summarized in comparison with nonfluorinated counterparts. 

Most derivatizations for gas chromatography are esterifications or etherifications. For example, analytes containing carboxyl groups are often converted into methyl [156], [161], pentafluorobenzyl [255]-[258], or triethyl esters [259]-[261], Analytes containing acidic hydroxyl groups (phenols, chlorophenols, glycol ethers) or amino groups (e.g.. aniline) can be derivatized with such per-fluorinated compounds as heptafluorobutyric anhydride, pentafluoropropionic anhydride [169], or pentafluorobenzoyl chloride [262]. 

The OH deformation band is not well defined. Emeleus et al [26,27] assigned it as near 940 cm" in some fluorinated compounds, and others have suggested it occurs near 1030 cm" where it is likely to be obscured by other absorptions [22]. Ryskin and Stavitskaya [46] prefer an assignment near 1280 cm" and this has been supported by deuteration studies by Thomas [43]. However, it is clear that this absorption is of very much less use for identification than is the corresponding band of dimeric carboxylic acids. 

Common silver compounds such as silver nitrate catalyzed the decarboxylative fluorination of carboxylic acids (Schane 7.23 and Example 7.10) [36]. Selectfluor served as the fluorine source for this chanistry, and simply refluxing the reagents in acetone/water mixtures generated good to excellent yields of the fluorinated compounds. Not only was the reaction successful in the presence of water, but also water was a critical component of the... 

As a result of the increased uptake of pharmaceutical compounds containing fluorine substituents, efficient synthetic methods are sought for the introduction of fluorine into small organic compounds. A recent example reported by Gustafsson et al. demonstrated the synthesis of fluori-nated alcohols, aldehydes, and carboxylic acids using dieth-ylamino sulfur 6 (DAST) in a polytetrafluoroethylene (PTFE) tube reactor. Employing a reaction time of 16 minutes and a temperature of 70°C (at 5 bar pressure), the authors were able to isolate the fluorinated compound in yields ranging from 40% to 100% (Scheme 6.3). 

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