Heptafluorobutyryl anhydride

Amino acids (chiral analysis) Pentafluoracetic anhydride Heptafluorobutyryl anhydride Esterification with deuterium Nkoihara and... 

Chromatography.—Considerable attention is being paid to chromatographic methods for the separation and recognition of bile acids and their derivatives. The analysis (g.l.c.) of mixtures of bile acids and their conjugates is reported to be simplified by direct conversion into heptafluorobutyrate derivatives, which occurs with simultaneous deconjugation.The carboxyl function is apparently converted into its volatile mixed cholanyl-heptafluorobutyryl anhydride. Ethyl-dimethylsilyl ethers of bile acid ethyl esters are also reported to be suitable for... 

The use of acetic anhydride for the acetylation of phenols has been described in some papers [86,87]. Determination of chlorophenols in freshwater, wastewater, and seawater using acetylation and BCD was reported by Abrahamsson and Xie [87]. They compared two derivatization procedures, pentafluorobenzoylation versus acetylation, and concluded that the acetylated derivatives gave better separation on the capillary column. Derivatization using heptafluorobutyryl in combination with GC-BCD [88] involves an extraction of the acidified sample into benzene before derivatization. Another method describes the conversion of eight phenols (phenol, cresols, and xylenols) into corresponding bromophenols after reaction with bromine followed by an analysis using GC-BCD [91 ]. 

Perflnoroalkylation is often performed with bis(perfluoralkanoyl)peroxides, e.g. bis(triflnoroacetyl)peroxide and bis(heptafluorobutyryl)peroxide, which are thermally stable, convenient to nse, and can be obtained from the corresponding anhydrides and hydrogen peroxide in Freon 113 (CFCI2CF2CI) as a solvent. Perfluorooxaalkanoylperoxides provide the same reactivity. The mechanism of the transformation inclndes oxidation of thiophene to radical cation, followed by reaction with perflnoro radical to produce 2-perfluoroalkylthiophenes [50],... 

The abbreviations used are as follows TMAH = trimethylanilinium hydroxide, Bui = 1-iodobutane, PrI = 1-iodopropane, EtI = iodoethane, Mel = methyl iodide, AA -acetic anhydride, HFB = heptafluorobutyryl, HFBA = Heptafluorobutyric anhydride, TFA = trifluoroacetyl, TFAA = trifluoroacetic anhydride, PFP = pentafluoropropanyl, PPT A = pentfluoropropionic anhydride, BSTFA = N, O-bis (timethylsilyl trifluoroac-etamide), MSTFA = N-methyl-N-trimethylsilyltrifluoroacetamide, MBTFA -N-methyl-b/5 (trifluoroacetamide), TMCS = trimethylchlorosilane, TFAP = (S)-(->-N-(trifluoroacetyl) prolyl, PBA = phenylboronic acid, and CB Chloride = 4-car-bethoxyhexafluorobutyryl chloride. 

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