Ceric trifluoroacetate

Among other oxidizing agents286 that have been used to accomplish the conversion of ArCHj to ArCHO are ceric ammonium nitrate,287 ceric trifluoroacetate,288 benzeneseleninic anhydride,257 KMnCV-EtjN,289 and silver(II) oxide.290 Oxidation of ArCHj to carboxylic acids is considered at 9 11. 

Oxidative coupling etc. of aromatic hydrocarbons with ceric trifluoroacetate from Ce(OH)4 + CFs CO2H (CF3 C02)2Ce(0H)2 [with (CFs COsO-... 

Amide nitrogens can be protected by 4-methoxy or 2,4-dimethoxyphenyl groups. The protecting group can be removed by oxidation with ceric ammonium nitrate.243 2,4-Dimethoxybenzyl groups can be removed using anhydrous trifluoroacetic acid.244... 

The N-desilylation of 1-trimethylsilyl- or 1 -(// rt-butyldimethylsilyl)-2-azctidinones is a commonly used process in 2-azetidinone chemistry. The leri-b11toxycarbonyI group is readily removed with trifluoroacetic acid, while the 4-methox-yphenyl protecting group is conveniently removed by ceric ammonium nitrate, or anodic oxidation (Scheme 87). 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

Most aromatic compounds, whether of high or low reactivity, can be nitrated, because a wide variety of nitrating agents is available. For benzene, the simple alkylbenzenes, and less reactive compounds, the most common reagent is a mixture of concentrated nitric and sulfuric acids,but for active substrates, the reaction can be carried out with nitric acid alone, or in water, acetic acid, acetic anhydride, or chloroform.Nitric acid in acetic anhydride/trifluoroacetic anhydride on zeolite H-(3 was used to convert toluene to 2,4-dinitrotoluene, and AcONOi on clay converted ethylbenzene to ortho-para nitro ethylbenzene. " In fact, these milder conditions are necessary for active compounds, such as amines, phenols, and pyrroles, since reaction with mixed nitric and sulfuric acids would oxidize these substrates. With active substrates, such as amines and phenols, nitration can be accomplished by nitrosation under oxidizing conditions with a mixture of dilute nitrous and nitric acids.A mixture of N02/02/Fe(acac)3 can be used for active compounds, as can NaN02 with trichloroisocyanuric acid on wet silica gel, or N2O4 and silica acetate. Trimethoxybenzenes were nitrated easily with ceric ammonium nitrate on silica gel, and mesitylene was nitrated in an... 

More frequently, the benzylic hydrogen is replaced by an acyloxy group on refluxing with ceric ammonium nitrate in 100% acetic acid [415], with lead tetraacetate [434, 437], or with lead tetrakis(trifluoroacetate) [435]. 

The esters were prepared from the phenol and the acid chloride plus DM AP (or from the acid plus trifluoroacetic anhydride). In these esters the steric hulk of the ortho substituents protects the carhonyl from nucleophilic reagents, making them difficult hydrolyze. Although the diisopropyl derivative can be cleaved with hot aqueous NaOH, the di-f-butyl derivatives could only be cleaved with NaOMe in a mixture of toluene and HMPA. The related 2,6-di-f-butyl-4-methoxyphenyl ester can be cleaved oxidatively with ceric ammonium nitrate. These hindered esters have found utility in directing the aldol condensation. ... 

OXIDATION, REAGENTS Acetyl nitrate. Bis(tri-n-butyltin)oxide. Bromine-Hexameth-ylphosphoric triamide. f-Butyl perbenzoate. Ceric ammonium nitrate. N-chlorosuc-cinimide-Dimethyl sulfide. Chromic add. Chromic anhydride. Chromic anhydride-Acetic anhydride. Chromic anhydride-Hexamethylphosphoric triamide. 2,3-Dichloro-5,6-dicyano-l,4-benzoquinone. Dimethyl sulfoxide. Dimethyl sulfoxide-Trifluoro-acetic anhydride. Diphenylseleninlc anhydride. Iodine tris(trifluoroacetate). Lead tetraacetate. N-Methylmorpholine -N-oxide. p-NitrobenzenesulfonyI peroxide. Oxygen, singlet. Palladlumfll) chloride. Peroxybcnzimidic acid. Phenylseleninyl chloride. N-Phenyl-l,2,4-triazoline-3,5-dione. Potassium chromate. Potassium superoxide. Pyri-dinium chlorodiromate. Salcomine. Silver carbonate-Celite. Sodium hypochlorite. Sulfuryl chloridc-Silica gel. Thallium(III) acetate. ThaUium(III) nitrate. Triphenyl phosphite ozonide. Trltyl tetrafluoroborate. Uranium hexafluoride. 

Phenols (e.g., phenol itself [CeHs-OH or Ar-OH], Table 6.10, item 2) and their esters (e.g., the trifluoroacetate ester of phenol [C6H5-O2CCF3 or Ar02CCH3], Table 6.10, item 3) have been oxidized with air and oxygen (O2), in neutral and alkaUne solutions, with and without ionic and/or radical catalysts and/or irradiation and in a variety of solvents. Enzymes (this chapter and Chapter 12) from a wide variety of sources have also been used. Frequently, oxidation of aromatic systems to phenols cannot be stopped before quinones and products of ring fragmentation occur and numerous, sometimes ill-defined, products result. Thus, as shown in Equation 6.80, oxidation of the polynuclear hydrocarbon chrysene with anunonium cerium(IV) sulfate [ceric ammonium sulfate, Ce(NH,)4(S04)4] is reported to produce 6H-benzo[d]naphtho[l,2-/>]pyran-6-one (8% yield) and a quinone (23% yield). The remainder of the product(s) (69%) was unidentified. 

AgO-MeOH-HjO/ Tl" trifluoroacetate/ ceric ammonium nitrate/" Ij-DMSO/ Mel-acetone-HjO/ FSO,Me-Uquid and on... 

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