Arylmethanes, oxidation

Addition of carboxylic acids to alkynes Acylation of aldehydes or ketones Bisdecarboxylation of malonic acids Oxidation of arylmethanes with CrOs and AC2O... 

Oxidation of Arylmethanes - Electrochemical Alternative Routes to the Etard Reaction... 

Drivers for Performing the Electrochemical Oxidations of Arylmethanes in Micro Reactors... 

The first study on the oxidation of arylmethanes used this reaction as a model to show the general advantages of electrochemical micro processing and to prove the feasibility of an at this time newly developed reactor concept [69]. Several limits of current electrochemical process technology hindered its widespread use in synthetic chemistry [69]. As one major drawback, electrochemical cells stiU suffer from inhomogeneities of the electric field. In addition, heat is released and large contents of electrolyte are needed that have to be separated from the product. 

Beneficial Micro Reactor Properties for Electrochemical Oxidations of Arylmethanes... 

Electrochemical Oxidations of Arylmethanes Investigated in Micro Reactors Organic synthesis 85 [OS 85] Oxidation of4-methoxy toluene to 4-methoxy benzaldehyde... 

Arylmethane leuco dyes are converted into di- or triarylmethane dyes on oxidation. This class of dye precursors sometimes is referred to as leuco di- or triphenylmethane dyes, or di- or triphenylmethane leuco dyes. The use of the term di- or triarylmethane dyes can be misleading as the central carbon atom is a carbonium ion. Instead, the term di- and triarylmethine dye is recommended for this class as it correlates with the well-known polymethine dyes. Nevertheless, it has not been commonly used. 

The preparation of tri arylmethane dyes proceeds through several stages formation of the colorless leuco base in acid media, conversion to the colorless carbinol base by using an oxidizing agent, e.g., lead dioxide, manganese dioxide, or alkali dichromates, and formation of the dye by treatment with acid. The oxidation of the leuco base can also be accomplished with atmospheric oxygen in the presence of catalysts. 

A good example is the oxidation of aromatic compounds by manganic or cobaltic acetates in acetic acid, in particular the oxidation of arylmethanes to arylmethyl acetates, which takes place as follows ... 

The oxidation of arylmethanes to carboxylic acids can also be brought about by alkaline ferricyanide, probably by a similar electron transfer mechanism i.e.,... 

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