Trifluoroacetic anhydride chloride

Formation - with trifluoroacetic anhydride or trifluoroacetyl chloride Cleavage - K2CO3, MeOH... 

Trifluoroethanol was first prepared by the catalytic reduction of trifluoroacetic anhydride [407-25-0] (58). Other methods iaclude the catalytic hydrogeaatioa of trifluoroacetamide [354-38-1] (59), the lithium aluminum hydride reductioa of trifluoroacetyl chloride [354-32-5] (60) or of trifluoroacetic acid or its esters (61,62), and the acetolysis of 2-chloro-l,l,l-trifluoroethane [75-88-7] followed by hydrolysis (60). More recently, the hydrogenation of... 

The reactivity of five-membered rings with one heteroatom to electrophilic reagents has been quantitatively compared in a variety of substitution reactions. Table 2 shows the rates of substitution compared to thiophene for formylation by phosgene and iV,AT-dimethylfor-mamide, acetylation by acetic anhydride and tin(IV) chloride, and trifluoroacetylation with trifluoroacetic anhydride (71AHC(13)235). 

Acylation of various oxygen functions by use of common and commercially available fluonnated 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 nonfluonnated 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)... 

These esters were prepared from the phenol and the acid chloride, plus DMAP (or from the acid plus trifluoroacetic anhydride). Although the diisopropyl derivative can be cleaved with hot aqueous NaOH, the di-r-butyl derivatives could only be cleaved with NaOMe in a mixture of toluene and HMPA. The related... 

Because of the high cost and hygroscopic nature of trifluoroacetic anhydride, a new process, based on dimethylaniline and acrylyl chloride, was considered. Yields averaged 46% and product purities averaged 93.5% (Refs 2, 3 4) ... 

Activating agents, such as trifluoroacetic anhydride 1,1 -carbonyldiimidazolc carbodiimides sulfonyl, tosyl, and picryl chlorides and a range of phosphorus derivatives can promote direct solution reactions between dicarboxylic acids and diols or diphenols in mild conditions. The activating agents are consumed during the reaction and, therefore, do not act as catalysts. These so-called direct polycondensation or activation polycondensation reactions proceed via the in situ transformation of one of the reactants, generally the carboxylic acid, into a more... 

Treatment of N-benzoyl-L-alanine with oxalyl chloride, followed by methanolic triethylamine, yields methyl 4-methyl-2-phenyloxazole-5-carboxylate 32 <95CC2335>. a-Keto imidoyl chlorides, obtained from acyl chlorides and ethyl isocyanoacetate, cyclise to 5-ethoxyoxazoles by the action of triethylamine (e.g.. Scheme 8) <96SC1149>. The azetidinone 33 is converted into the oxazole 34 when heated with sodium azide and titanium chloride in acetonitrile <95JHC1409>. Another unusual reaction is the cyclisation of compound 35 to the oxazole 36 on sequential treatment with trifluoroacetic anhydride and methanol <95JFC(75)221>. 

Acid anhydrides behave in a similar way to acid chlorides. In this paragraph is included an accident that is the result of a very violent interaction of trifluoroacetic anhydride with DMSO. This reaction can only be controlled by cooling at -40°C, in a solution with dichloromethane. 

To a 300-ml. three-necked flask equipped with a glass Trubore stirrer and two loose-fitting ground-glass stoppers are added 46.2 g. (0.22 mole) of trifluoroacetic anhydride and SO ml. of methylene chloride (Note 1). The stirred solution is cooled in an ice bath, and 5.40 ml. (0.20 mole) of 90% hydrogen peroxide is added from a 10-ml. graduated cylinder in ca. l-ml. portions over a period of 10 minutes (Notes 2, 3, and 4). When the mixture has become homogeneous, it is allowed to warm to room temperature for a few minutes and is then cooled once more in an ice bath to 0°. 

Several laboratories have reported that Swern oxidation of alcohols can be accompanied of a-chlorination of keto or (1-keto ester groups. Undesired electrophilic chlorination can be avoided by use of oxalyl chloride (1.05 equiv.) and DMSO (2.5 equiv.) in stoichiometric amounts or by use of acetic anhydride or trifluoroacetic anhydride in place of oxalyl chloride.1... 

Biogenic amines chloride followed by derivatization with trifluoroacetic anhydride Acetic anhydride Gerhardt (2001) Baker etal. (1994)... 

Further work by Baum and co-workers showed that the nitration of l,l-diamino-2,2-dinitroethylenes with trifluoroacetic anhydride and nitric acid in methylene chloride yields 1,1,1-trinitromethyl derivatives via addition of nitronium ion to the double bond of the enamine such treatment also resulting in the A-nitration of the products. In this way, trini-tromethyl derivatives like (185) and (188) are obtained. Further treatment of these trinitromethyl derivatives with aqueous potassium iodide results in reductive denitration and the formation... 

Trifluoroacetic acid (CF3CO3H) sits between peroxyacetic acid and peroxydisulfuric acid in oxidizing potential. Anhydrous solutions of peroxytrifluoroacetic acid in methylene chloride can be prepared by the addition of 90 %+ hydrogen peroxide to a solution of trifluoroacetic anhydride in methylene chloride containing a trace of sulfuric acid. Solutions of peroxytrifluoroacetic acid prepared from less concentrated hydrogen peroxide solution or trifluoroacetic acid are less reactive to arylamines. 

Chemical deoxygenation of sulfoxides to sulfides was carried out by refluxing in aqueous-alcoholic solutions with stannous chloride (yields 62-93%) [186 Procedure 36, p. 214), with titanium trichloride (yields 68-91%) [203], by treatment at room temperature with molybdenum trichloride (prepared by reduction of molybdenyl chloride M0OCI3 with zinc dust in tetrahydrofuran) (yields 78-91%) [216], by heating with vanadium dichloride in aqueous tetrahydrofuran at 100° (yields 74-88%) [216], and by refluxing in aqueous methanol with chromium dichloride (yield 24%) [190], A very impressive method is the conversion of dialkyl and diaryl sulfoxides to sulfides by treatment in acetone solutions for a few minutes with 2.4 equivalents of sodium iodide and 1.2-2.6 equivalents of trifluoroacetic anhydride (isolated yields 90-98%) [655]. 

A very useful group of procedures for oxidation of alcohols to ketones have been developed which involve DMSO and any one of several electrophilic reagents, such as dicyclohexylcarbodiimide, acetic anhydride, trifluoroacetic anhydride, oxalyl chloride, or... 

Methods of acylating pyrrole similar to the present one have been reported using oxalyl chloride,5 trifluoroacetic anhydride,6 carbamic acid chloride,7 and trichloroacetyl chloride.8 In the last preparation, it was necessary to separate the product from highly colored by-products by alumina chromatography. Pyrrol-2-yl trichloromethyl ketone has also been prepared by the interaction of pyrrolylmagnesium halide and trichloroacetyl chloride.9... 

The general picture emerging is that acid chlorides are sufficiently electrophilic to N-acylate carbazole directly but that acid anhydrides require a Lewis acid or protonic acid catalyst. Direct and efficient N-trifluoroacetyla-tion with trifluoroacetic anhydride nicely illustrates the balance, this more reactive anhydride requiring no catalyst. ... 

TNB, Methanol, Potassium iodide, Hydrochloric acid, Sodium bisulfite, Methylene chloride, Magnesium sulfate Hydroxylamine hydrochloride, Glyoxal, Sodium carbonate, Ethanol, Chlorine, Chloroform, Methanol, Ethylenediamine, Ethylene glycol, Sodium hydroxide, Trifluoroacetic anhydride, Nitric acid, Acetone... 

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