Cycloheptatrienecarboxylic acids

Ottmann with the following results. They found that a trace of heavy metal catalyzes decomposition of the diazo ester and so heated a mixture of the ester with 20 parts of benzene in a glass insert of an autoclave at 136-140° and so obtained 7-carbo-ethoxynorcaradiene (1) in much improved yield. The ester (I) is converted into the amide (2), which on alkaline hydrolysis undergoes rearrangement to a mixture of four cycloheptatrienecarboxylic acids. Characterization of these acids led to assignment of the structures formulated. 

An interesting new route to tropane derivatives, particularly to anhydroecgonine, has been outlined (122). Methylamine reacts with cycloheptatrienecarboxylic acid giving rise to ( )-anhydroecgonine, that is, trop-2-enecarboxylic acid. This reaction may be looked upon as a reversal of the elimination reaction that takes place with tropinone methiodide and its hydroxy and bromo derivatives (121). 

Cycloheptatrienecarboxylic acid and its related nitrile have been utilised as intermediates in the preparation of tropylium salts, especially in early work on them, since they can be readily obtained by the reaction of diazoacetic ester or diazoacetontrile with benzene [33]. For example acidified permanganate converts cycloheptatrienecarboxylic acid into a mixture of tropylium salts and benzaldehyde, the former being obtained in up to 40% yield [34]. Other oxidising agents have also been used [34], The benzaldehyde probably arises from further oxidation of the tropylium cation. 

This solution gave cycloheptatrienecarboxylic acid on addition of... 

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See also in sourсe #XX -- [ ]

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