Pertrifluoroacetic acid oxidation

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

Figure 5 Plot of pertrifluoroacetic acid oxidation aliphatic proton yield data derived from P.M.R. and elemental analysis.

Product Composition of Brown Coal Lithotypes Pertrifluoroacetic Acid Oxidation Mixtures... 

Table IL Pertrifluoroacetic Acid Oxidation Product Distribution (—1 0 X 2 C/3 m H > r 1...

In a synthetic sequence involving thietanoprostanoids45, peroxydodecanoic acid was successfully used to oxidize a hydroxysulphoxide to the corresponding hydroxysulphone (equation 14). The use of pertrifluoroacetic acid in this case apparently produced unidentifiable products. 

Perphthalic acid <550SC(3)619) is an even milder reagent that works even at —20 to 20 °C. Performic, permaleic and pertrifluoroacetic acids are strong oxidizing agents and they are recommended for AT-oxidation of the least reactive substrates. The last of the three is the most commonly used, especially for the oxidation of highly deactivated substrates (Scheme 16) such as perchloropyridine (electronic deactivation) (74MI20501) and 2,6-dibromopyridine (electronic and steric deactivation) (equation 35). 

Oxidation with Stoichiometric Oxidants. Certain peracids reacting with alkanes yield alcohols. Peracetic acid,68 69 perbenzoic acid,70 m-CPBA,71,72 and nitroper-benzoic acids may be used. Alcohols or an equilibrium mixture of the alcohol and the trifluoroacetate77 are formed on the action of pertrifluoroacetic acid. A high degree of regioselectivity (better than 97%), specifically, preferential attack at the tertiary C—H bonds, is usually observed ... 

The oxidation of oximes offers an attractively simple route to nitroalkanes from carbonyl compounds. The most effective reagent is pertrifluoroacetic acid in acetonitrile in the presence of sodium hydrogen carbonate as a buffer. Yields are improved by the addition of small quantities of urea to remove oxides of nitrogen. The reaction is illustrated by the conversion of dipropyl ketoxime into 4-nitroheptane (Expt 5.190). 

The epoxidation reaction is achieved most conveniently by employing m-chloroperbenzoic acid (or perbenzoic acid) in a solvent such as chloroform. The use of other peracids, such as peracetic acid or pertrifluoroacetic acid, give lower yields of the oxirane since the oxide may be readily cleaved to form the monoester of the diol (e.g. Section 5.4.5, p. 547). 

Oxidation of DCC with pertrifluoroacetic acid affords N-trifluoromethyl-N,N -... 

The lithotype profile was investigated in greater detail with the product composition of the different brown coals being reported in Tables 1 and 2. A distinct decrease in the total concentration of detectable oxidation products occurs with darker lithotypes (Table 1). This result is consistent with increasing aromaticity (Figure 2) and the preferential attack on aromatic structures by the pertrifluoroacetic acid reagent. The total destruction of the tertiary structure within the brown coal lithotypes is evidenced by their low yield of insoluble products (Residue) which is primarily composed of mineral matter. 

Aromatic chlorination,4 Titanium tetrachloride in the presence of an oxidizing agent such as pertrifluoroacetic acid chlorinates a variety of aromatic substrates. Yields are high in the case of activated aromatics such as phenol benzoic acid and nitrobenzene do not react. 

Potassium permanganate. Dimethyl sulfide-Chlorine. Dimethyl sulfoxide. Dimethyl sulfoxide-Chlorine. Dimethylsulf-oxide Sulfur trioxide. Dipyridine chro-mium(VI) oxide. Iodine. Iodine-Potassium iodide. Iodine tris(trifluoroacetate). Iodosobenzene diacetate. Isoamyl nitrite. Lead tetraacetate. Manganese dioxide. Mercuric acetate. Mercuric oxide. Osmium tetroxide—Potassium chlorate. Ozone. Periodic acid. Pertrifluoroacetic acid. Potassium ferrate. Potassium ferricyanide. Potassium nitrosodisulfonate. Ruthenium tetroxide. Selenium dioxide. Silver carbonate. Silver carbonate-Celite. Silver nitrate. Silver oxide. Silver(II) oxide. Sodium hypochlorite. Sulfur trioxide. Thalli-um(III) nitrate. Thallium sulfate. Thalli-um(III) trifluoroacetate. Triphenyl phosphite ozonide. Triphenylphosphine dibromide. Trityl fluoroborate. 

Pertrifluoroacetic acid-Boron trifluoride (1, 826 2, 316). Hart1 has reviewed oxidation with this system. 

Oxidation of aromatic compounds. Chambers et aO explored oxidation of aromatic hydrocarbons with anhydrous pertrifluoroacetic acid in methylene chloride and, except in the case of benzene and toluene, obtained mixtures shown to contain small amounts of phenols and quinones, as exemplified by the case of m-xylene ... 

Oxidation methods BAEVER-ViixioEn reaction Caro s acid. m-Chloroperbenzoic acid. Hydrogen peroxide. Peracetic acid. Permaleic acid, pertrifluoroacetic acid. 

Reaction. For an interesting oxidative rearrangement, see Pertrifluoroacetic acid. 

Oxidation. Hexafluoroacetone (available from Aldrich) and hydrogen peroxide form a complex which functions as a peracid. Thus it can be used in the Baeyer-Villiger reaction and for oxidation of a primary aromatic amine to a nitro compound. Preliminary results, however, indicate that the adduct is less powerful than pertrifluoroacetic acid.1... 

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