Sodium trifluoroacetate and

Cheaper sources of tnfluoromethyl groups have been the goal of several groups The use of sodium trifluoroacetate and copper (I) iodide in dipolar aprotic solvents gave regiospecific trifluoromethylation of aromatic halides [202] (equation 136)... 

TrifiuoroacetyUuion. Trifluoroacetic anhydride acylates primary and secondary alcohols with great ease, but the esters are so extremely sensitive to hydrolysis that it is sometimes necessary to avoid contact with water in the workup. Thus Tatlow and co-workers refluxed briefly a mixture of p-nitrobenzyl alcohoi, trifluoroacetic anhydride, and sodium trifluoroacetate and distilled the mixture with four portions of carbon tetrachioride at reduced pressure to remove excess anhydride and trifluoroacetic acid. The ester was then extracted from the sodium trifluoroacetate... 

Deoxygenation of epoxides. Epoxides react with trifluoroacetic anhydride (1 equiv.) and sodium iodide (1 equiv.) in CH3CN-THF (1 1) to give a jS-iodotri-fluoroacetate when this product is treated with sodium iodide (3 equiv.) in the same solvent system, an olefin, sodium trifluoroacetate, and iodine are formed. The olefin has the same geometry as the starting epoxide yields of the olefin are 80-95%. Presumably, trifluoroacetyl iodide is generated in situ from the anhydride and Nal. ... 

The nucleophilic trifluoromethylation, which is based on the heating of A -methyl-2-iodoindole 63 with 10 equivalents of sodium trifluoroacetate and an equimolar amount of copper(l) iodide in A-methylpyrrolidinone, afforded A -methyl-2-trifluoromethylindole 60c in 65 % yield [30],... 

Through direct trifluoromethylation, 7-methyl-3-trifluoromethyl-benzo[f>]thio-phene 179 was prepared in 54 % yield from 7-methyl-3-bromobenzo[( ]thiophene 59. The reaction took place with sodium trifluoroacetate and copper(I) iodide in N-methylpyrrolidone at 180 °C [35]. 

However, this method is appHed only when esterification cannot be effected by the usual acid—alcohol reaction because of the higher cost of the anhydrides. The production of cellulose acetate (see Fibers, cellulose esters), phenyl acetate (used in acetaminophen production), and aspirin (acetylsahcyhc acid) (see Salicylic acid) are examples of the large-scale use of acetic anhydride. The speed of acylation is greatiy increased by the use of catalysts (68) such as sulfuric acid, perchloric acid, trifluoroacetic acid, phosphoms pentoxide, 2inc chloride, ferric chloride, sodium acetate, and tertiary amines, eg, 4-dimethylaminopyridine. 

Androst-4-ene-3,17-dione. Testosterone (0.58 g, 2 mmoles) is dissolved in a solution prepared from 3 ml of benzene, 3 ml of dimethyl sulfoxide, 0.16 ml (2 mmoles) of pyridine and 0.08 ml (1 mmole) of trifluoroacetic acid. After addition of 1.24 g (6 mmoles) of dicyclohexylcarbodiimide, the sealed reaction flask is kept overnight at room temperature. Ether (50 ml) is added followed by a solution of 0.54 g (6 mmoles) of oxalic acid in 5 ml of methanol. After gas evolution has ceased ( 30 min) 50 ml of water is added and the insoluble dicyclohexylurea is removed by filtration. The organic phase is then extracted twice with 5 % sodium bicarbonate and once with water, dried over sodium sulfate and evaporated to a crystalline residue (0.80 g) which still contains a little dicyclohexylurea. Direct crystallization from 5 ml of ethanol gives androst-4-ene-3,17-dione (0.53 g, 92%) in two crops, mp 169-170°. 

Although catalytic hydrogenation is the method most often used, double bonds can be reduced by other reagents, as well. Among these are sodium in ethanol, sodium and rerr-butyl alcohol in HMPA, lithium and aliphatic amines (see also 15-14), " zinc and acids, sodium hypophosphate and Pd-C, (EtO)3SiH—Pd(OAc)2, trifluoroacetic acid and triethylsilane (EtsSiH), and hydroxylamine and ethyl acetate.However, metallic hydrides, such as lithium aluminum hydride and sodium borohydride, do not in general reduce carbon-carbon double bonds, although this can be done in special cases where the double bond is polar, as in 1,1-diarylethenes and in enamines. " °... 

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>. 

Treatment of methyl p-chlorobenzoate with an equivalent amount of commercial potassium silanolate 97 in abs. diethyl ether affords, after 4h, pure, anhydrous potassium p-chlorobenzoate in 84% yield and methoxytrimethylsilane 13 a. Trimethylsilyl trifluoroacetate reacts hkewise with sodium trimethylsilanolate 96 in THF to give sodium trifluoroacetate, in 98% yield, and hexamethyldisiloxane 7 [119] (Scheme 4.45). 

As a general rule, peracetylation is most useful for compounds below Mr 2000, particularly those that have been reduced with sodium borohydride and still contain some salt. The best procedure for peracetylation is based on the method of Bourne and coworkers. Samples are dissolved in 2 1 (v/v) trifluoroacetic anhydride-acetic acid and the solutions kept for 10 min at room temperature. Reagents are removed under a stream of nitrogen, and a solution of the product in chloroform is washed with water to remove salts, and dried the peracetylated sample is dissolved in methanol for the f.a.b. analysis. 

Diethyl succinate had been introduced into a mixture of sodium hydride and ethyl trifluoroacetate at 60°C. The medium detonated ten to twenty minutes after starting the addition of succinate. Two accidents that are identical to this one have been described. 

Thermally unstable at 22°C and explosive in the gas phase at pressures above 27-62 mbar [1], there is also an explosion hazard during distillation and trapping at -78°C [2], The crude (80%) material prepared by action of 3% fluorine in nitrogen on sodium trifluoroacetate [3] has, however, been used synthetically for 3 years without mishap [4]. 

Acylation of diethyl succinate by ethyl trifluoroacetate in presence of sodium hydride and in absence of a solvent is hazardous, fire or explosion occurring on 2 occasions some 10-20 min after adding a tittle of the succinate to the hydride-trifluoroacetate premixture at 60°C. Presence of a solvent appears to eliminate the hazard. 

A" 0-Butenolide, 46, 22 /-Butyl alcohol, in synthesis of phenyl /-butyl ether, 45, 89 reaction with sodium cyanate and trifluoroacetic acid, 48, 32 /-Butyl azidoacctatc, 46, 47 hydrogenation of, 45, 47 /-Butyl carbamate, 48,32 /-Butyl chloroacetate, reaction with sodium azide, 45, 47 /ra S-4-/-BuTYI,CYCLOHEXANOL, 47,16... 

MAS has been applied to a highly viscous cubic phase of a lyotropic LC formed by 1-monooleolyl-rac-glycerol and water in order to obtain liquid-like and 13C spectra.330 Deuterium, sodium, and fluorine NMR spectroscopy have been applied to study the phase behaviour of several dilute lamellar systems formed by low concentrations of an ra-hexadecylpyridinium salt, a sodium salt (e.g., NaBr, NaCl, or sodium trifluoroacetate), 1-hexanol, and D20.331 The 2H, 19F, and 23Na splittings were used to monitor the phase equilibria. The last two studies are motivated by the search of new lyotropic LC for the alignment of biomolecules. 

Trifluoroacetic acid is prepared by treating aaa trifluorotoluene with sodium dichromate and sulphuric acid for 15 days. 

The carbamates of alcohols, even those of tertiary alcohols can be prepared in good yields. The alcohol is stirred with 2 equivalents of sodium cyanates and trifluoroacetic acid at room temperature for few horns. 

Although most of these early reactions were conducted with allylic acetates, reactions of allylic carbonates, trifluoroacetates, and phosphates also occur. Sodium diethylmalonate also reacts with allylic alcohols in the presence of the iridium-triphenylphosphite catalyst. However, the alcohol itself does not act as a leaving group. Instead, transesterification occurs with one equivalent of malonate nucleophile to form a more labile ester leaving group. 

Marchand and co-workers reported a synthetic route to TNAZ (18) involving a novel electrophilic addition of NO+ NO2 across the highly strained C(3)-N bond of 3-(bromomethyl)-l-azabicyclo[1.1.0]butane (21), the latter prepared as a nonisolatable intermediate from the reaction of the bromide salt of tris(bromomethyl)methylamine (20) with aqueous sodium hydroxide under reduced pressure. The product of this reaction, A-nitroso-3-bromomethyl-3-nitroazetidine (22), is formed in 10% yield but is also accompanied by A-nitroso-3-bromomethyl-3-hydroxyazetidine as a by-product. Isolation of (22) from this mixture, followed by treatment with a solution of nitric acid in trifluoroacetic anhydride, leads to nitrolysis of the ferf-butyl group and yields (23). Treatment of (23) with sodium bicarbonate and sodium iodide in DMSO leads to hydrolysis of the bromomethyl group and the formation of (24). The synthesis of TNAZ (18) is completed by deformylation of (24), followed by oxidative nitration, both processes achieved in one pot with an alkaline solution of sodium nitrite, potassium ferricyanide and sodium persulfate. This route to TNAZ gives a low overall yield and is not suitable for large scale manufacture. 

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]. 

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