Its methyl derivatives yield the corresponding carboxylic acids when oxidized by potassium permanganate.
It is probable that tetrahydro acids are first formed, which suffer rearrangement to orthoketone carboxylic acids.
Amino derivatives similarly result from thio-ureas and a-haloid ketones; the oxy derivatives from a-sulphocyanoketones by the action of caustic alkali; and the carboxylic acids from chloro-aceto-acetic ester, &c. and thioamides.
Oxy-acids are carboxylic acids which also contain a hydroxyl group; similarly we may have aldehyde-acids, ketone-acids, &c. Since the more important acids are treated under their own headings, or under substances closely allied to them, we shall here confine ourselves to general relations.
Their alkyl derivatives readily oxidize to pyrazine carboxylic acids.