Pyridinium fluorochromate oxidation

Pyridinium fluorochromate oxidizes cycloalkanones to the corresponding 1,2-diketones. " The kinetics have been studied in aqueous acetic-perchloric acid mixtures relative reactivities are explained in terms of conformational and steric... 

Pyridinium fluorochromate oxidized D-glucose to yield D-arabinose... 

The uses of the versatile oxidant pyridinium chlorochromate have been reviewed. Pyridinium chlorochromate has been used for the oxidation of methyl 5-hydroxypentanoate to the aldehyde, an intermediate useful in the synthesis of leukotrienes, and the same reagent oxidatively cleaves secondary vicinal diols to the corresponding aldehydes. The reactivity of the chlorochromate ion as an oxidant can be influenced by the counter-ion. For example, the 4-dimethylaminopyridinium salt is a mild, selective reagent for the oxidation of allylic and benzylic alcohols. Pyridinium fluorochromate oxidizes primary and secondary alcohols to aldehydes and ketones respectively in dichloromethane solution, and shows a less pronounced acidity compared with the chloro-... 

Correlation of structure and reactivity in the oxidation of substituted aromatic anils by pyridinium fluorochromate (PFC) has been attempted using Grunwald-Winstein and Hammett equations. The stoichiometry between the substrate and oxidant is 1 2 in the oxidation of cyclic ketones by PFC to 1,2-diketones. PFC oxidation of secondary alcohols has been investigated. ... 

The oxidation of substituted benzaldehydes to substituted benzoic acids by pyridinium fluorochromate (PFC) has been studied, and it has been found that the reaction is first order with respect to pyridinium fluorochromate but is of complicated order with respect to the aldehyde. The following scenario was proposed to account for this behavior ... 

Potassium superoxide. Pyridinium chlorochromate. Pyridinium dichromate. Pyridinium fluorochromate. Silver(I) oxide. Silver(II) oxide. Sodium chlorite. Sodium hypochlorite. Sodium periodate. Sodium peroxide. Thallium(in) trifluoroacetate. Trifluoroperacetic acid. 

Kinetics and activation parameters for the oxidation of phenol with tetrakis(pyridine) cobalt(II) chromate have been determined.16 The oxidation of oximes of cyclopen-tanone, cyclohexanone, and cycloheptanone with pyridinium fluorochromate is first order each in the oxidant and oxime. The observed reactivity sequence has been rationalized on the basis of I-strain.17... 

Oxidation of several primary aliphatic alcohols with potassium dichromate, pyri-dinium dichromate, quinolinium dichromate (QDC), imidazolium dichromate, nico-tinium dichromate, isonicotinium dichromate, pyridinium fluorochromate (PFC), quinolinium fluorochromate, imidazolium fluorochromate, pyridinium chlorochromate (PCC), quinolinium chlorochromate (QCC), and pyridinium bromochromate (PBC), in aqueous acetic acid and in the presence of perchloric acid, showed similar kinetics. The values of the reaction constants did not differ significantly, indicating operation of a common mechanism.1... 

Pyridinium fluorochromate is a stable solid, which can be stored for long periods." h is as reactive as PCC, but slightly less acidic (pH of a 0.01 M solution = 2.4S compared to 1.7S for PCQ, and thus substrates with acid labile groups can be oxidized without the need to add a buffer." With 1.S equiv. of oxidant in dichloromethane at room temperature, primary and secondary alcohols are oxidized to aldehydes and ketones in high yield (Table 9). Unfortunately, ( )/(Z)-isomerization has been observed during the oxidation of allylic alcohols." ... 

Allylic oxidation. Steroidal 5-en-7-ones are produced in good yields (6 examples. 86-88%) from A -steroids on heating with pyridinium fluorochromate with molecular sieves in refluxing benzene. 

Secondary alcohols are oxidized by H5IO6 in the presence of various chromium catalysts to ketones [1321-1325], while primary alcohols can be oxidized to aldehydes or to carboxylic acids depending on the catalyst. Primary alcohols in the presence of pyridinium chlorochromate (PCC)[1322] or chromium (III) acetylacetonate, Cr(acac)3 [1321] are oxidized to aldehydes or ketones in excellent yields, while the use of CrOj [1326,1327] or pyridinium fluorochromate [1323] as catalysts results in the oxidation to carboxylic acids. The periodic acid promoted oxidation of primary and secondary alcohols to carbonyl compounds can also be catalyzed by Cu(II) derivatives [1328,1329], by bromide anion [1330] and by TEMPO [1331]. 

Oxidative deoximation of aldo- and keto-oximes by tetraethylammonium chlorochro-mate in DMSO is first-order in oxime and oxidant, and the kinetic study was extended to 19 organic solvents. Similar kinetic behaviour was found for imidazolium fiuorochromate in the case of acetaldoxime, the same solvent survey was performed. Pyridinium fluorochromate as oxidant was also studied in DMSO. ... 

Oxidations by imidazolium fluorochromate (IFC), pyridinium fluorochromate (PFC), quinolinium fluorochromate (QFC), quinaldinium fluorochroma (QnFC), and tripropy-lammonium fluorochromate (TPAFC) are also reported. 

Suitable mechanisms have been proposed following determination of the kinetic and activation parameters for oxidation of 2-naphthol and cyclic ketones by nicotinium dichromate some a-amino acids by tripropylammonium fluorochromate " distyryl ketone by quinaldinium fluorochromate methanol by benzyltriethylammonium chlorochromate catalysed by 1,10-phenanthroline substituted benzyl alcohols by tetraethylammonium bromochromate L-cysteine by pyridinium bromochromate lactic acid and 3,5-dimethyl-2,6-diaryl piperidin-4-one oximes by pyridinium chlorochromate allyl alcohol by IDC benzophenoxime by bispyridine silver(I) dichromate and alkyl phenyl sulfides by cetyltrimethylammonium dichromate. A non-linear Hammett plot obtained for the oxidation of substituted benzyl alcohols by IDC has been attributed to the operation of substituent effect on two steps of the proposed mechanism. " Kinetic and activation parameters for oxidation of o-toluidine and of A-methyl-2,6-diphenyl piperidin-4-one oxime and its 3-alkyl derivatives by sodium dichromate have been determined and suitable mechanisms have been suggested. Micellar catalysis in the 1,10-phenanthroline-promoted chromic acid oxidation of propanol... 

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