Butyryl fluoride

As will be seen later, benzoyl fluoride exhibits Bronsted-acid catalysis in aqueous media86 and was thought to be the only acyl derivative to do so although alkyl fluorides are known to behave in this way also. For benzyl fluoride, the acid-catalysed rate is reported to show dependence on /i0104 105. Satchell87 studied the solvolysis of benzoyl and butyryl fluoride in 60 40 (v/v) dioxan-water mixtures (for which h0 data are known)106. The solvolysis of each compound is catalysed by acid, but does not follow h0. With excdss of solvent the observed first-order loss of acyl derivative obeys the expression... 

Carboxylic acid fluorides are not of particular preparative importance since the reactions that can be carried out with them proceed analogously with the cheaper carboxylic acid chlorides. These fluorides are very stable, even towards hydrolysis. Formyl fluoride can be kept at room temperature for several hours before it decomposes into CO and HF. The preparation of carboxylic acid fluorides from the corresponding chlorides and KF was mentioned on page 204. If butyric anhydride is heated gradually to 180° with KHF2, butyryl fluoride, b.p. 67° 1167 mm, distils off, and benzoyl fluoride, b.p. 155-156°, can be obtained analogously from benzoic anhydride at 190-240°. KF can also be used in place of KHF2. Yields are around 80-90%.1079... 

Fluorosulfonic acid added drop wise with cooling and stirring at ca. —5° to n-butyric anhydride, and warmed slowly to room temp, under reduced pressure n-butyryl fluoride. Y ca. 95%. F. e., also carboxylic acid chlorides with chlorosulfonic acid, s. M. Schmidt and K. E. Pichl, B. 98, 1003 (1965). ... 

This technique can be applied to prepare ni-a-fluoromcthylputrescine (5-fluoropentane 1,4-diamine), a potent irreversible inhibitor of E coh ornithine decarboxylase, from 4-phthahmido-l-butyryl chloride, diazomethane, and hydro gen fluoride-pyridine [94 95]... 

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