Ceric ammonium nitrate carboxylic acids

Carboxylic acids, a-bromination of 55, 31 CARBOXYLIC ACID CHLORIDES, ketones from, 55, 122 CARBYLAMINE REACTION, 55, 96 Ceric ammonium nitrate [Ammonium hexa mtrocerate(IV)[, 55, 43 Chlorine, 55, 33, 35, 63 CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Cinnamomtnle, a-phenyl- [2-Propeneni-tnle 2,3-diphenyl-], 55, 92 Copper(l) iodide, 55, 105, 123, 124 Copper thiophenoxide [Benzenethiol, copper(I) salt], 55, 123 CYCLIZATION, free radical, 55, 57 CYCLOBUTADIENE, 55, 43 Cyclobutadieneiron tricarbonyl [Iron, tn-carbonyl(r)4-l,3-cyclo-butadiene)-], 55,43... 

Among other oxidizing agents that have been used to accomplish the conversion of ArCHs to ArCHO are ceric ammonium nitrate, ° ceric trifluoroa-cetate, and silver(II) oxide.Oxidation of ArCHa to carboxylic acids is considered at 19-11. 

Allylic carboxylation. Diethyl oxomalonate (1) undergoes a thermal ene reaction with mono-, di-, and trisubstituted alkenes at 145 180°. The reaction is also subject to catalysis with Lewis acids, which can lead to a different ene product. The products are a-hydroxymalonic esters. The corresponding malonic acids are converted to carboxylic acids by bisdecarboxylation with NaI04 and a trace of pyridine- or with ceric ammonium nitrate (CAN). Diethyl oxomalonate then functions as an cnophilic equivalent of C02. 

Protection2 and activation1 of carboxylic acids. Carboxylic acids react with 1 in the presence of a 2-chloropyridinium salt, proton sponge, and DMAP to form amides (2). These amides are stable to acids and bases but deprotection is possible with oxidative hydrolysis with ceric ammonium nitrate (CAN). If the oxidation is carried out in the presence of an amine, an amide is obtained in 70-95% yield. For this purpose, the combination of copper(II) oxide and ceric pyridinium chloride is far superior to CAN.4 No racemization was observed in the benzoylation of an a-amino ester. 

Oxidation of 3,4-dihydropyrimidin-2(l //)-oncs (DHPMs) with ceric ammonium nitrate (CAN) in acetic acid resulted in ethyl 2,4-dioxo-6-phenyltetrahydropyrimidin-5-carboxylates as the major product. However, DHPMs undergo a regioselective oxidation with CAN in the presence of sodium hydrogencarbonate in neutral aqueous acetone solution to yield ethyl 6-meihyl-4-aryl(alkyl)pyrimidin-2(l //)-one-5-carboxylates. A mechanism involving a nitrolic acid intermediate has been suggested.72... 

Oxidation of these complexes releases the apical carbon atom and its substituent in the form of an organic derivative.2 Thus ceric ammonium nitrate oxidation of an RCCo3(CO)9 complex produces the carboxylic acid, RC02H, when the reaction is carried out in aqueous acetone. Thermolysis of RCCo3(CO)9 produces acetylenes or acetylene hexacarbonyl dicobalt complexes, depending on the reaction conditions. Useful applications of these cluster complexes in organic synthesis remain to be developed. 

Carbon suboxide, 52 Carbonylation, 148, 149, 216 Carbonyl chlorofluoride, 48, 54 Carbonyl cyanide, 60-61 N,N -Carbonyldiimidazole, 61 1,1-Carbonyldi-l,2,4-triazole, 61 N-Carbonylsulfamic acid chloride (N-Carbonylsulfamyl chloride), 61 Carboxamides, 270 Carboxamine-N-sulfochlorides, 70 p-Carboxybenzenediazonium chloride, 62 p-Carboxybenzenesulfonazide, 62 Carboxylation, 15, 16 Carboxylic acid anhydrides, 133 Carboxylic acid N,N-dimethylamines, 153 Carboxylic anhydrides, 409-410 p-Carboxyphenylhydrazones, 62 Cardenolides, 130, 131 (S-Carotene, 19 /-Carvone, 451, 452 i//-Caryophyllene, 149, 150 Catechol, 65, 233 Catechol amines, 159 Catechyl phosphorus tribromide, 63 Catechyl phosphorus trichloride, 63 Cis-Cecropia juvenile hormone, 261 Cedrene, 234, 235 a-Cedrene, 349 /3-Cedrene, 349 Cendranoxide, 234, 235 Cephalosporin C, 48 Ceric ammonium nitrate, 63-65 Ceric sulfate. 65 Cesium fluoride, 346 trans-Chalcone oxide, 422 Chalcone phenylhydrazones, 257, 258 Chalcones, 406 Chloramine, 65-66, 69 Chloranil, 66-67, 113, 116, 401,454... 

The p-methoxyphenyl group has recently been found suitable for alcohol protection, as the resulting ethers are stable both to acidic and basic conditions and can be cleaved by brief treatment with ceric ammonium nitrate. The same principle can be applied to carboxylic acid protection.Thus, the rather stable benzyl (64) and phenyl (65) esters can be cleaved as indicated by oxidation with DDQ or cerium(IV)(at pH 3) respectively. A recent total synthesis of (+)-Antimycin-A features the use of a... 

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