Carboxylic synonyms

Its methyl derivatives yield the corresponding carboxylic acids when oxidized by potassium permanganate.

On oxidation with chromic or nitric acids, or potassium permanganate, it yields nicotinic acid or (3-pyridine carboxylic acid, C 5 H 4 N CO 2 H; alkaline potassium ferricyanide gives nicotyrine, C10H10N2, and hydrogen peroxide oxynicotine, C10H14N20.

7-dihydroxyxanthone, known as euxanthone, is prepared by heating euxanthic acid with hydrochloric acid or by heating hydroquinone carboxylic acid with 3-resorcylic acid and acetic anhydride (S.

7-trihydroxyxanthone, is found in the form of its methyl ether (gentisin) in gentian root; it is obtained synthetically by condensing phloroglucin with hydroquinone carboxylic acid.

Experience has shown that such mono-derivatives as nitro compounds, sulphonic acids, carboxylic acids, aldehydes, and ketones yield as a general rule chiefly the meta-compounds, and this is independent of the nature of the second group introduced; on the other hand, benzene haloids, amino-, homologous-, and hydroxy-benzenes yield principally a mixture of the orthoand para-compounds.