The carbonyl group is not ketonic in character since it yields neither an oxime nor hydrazone.
The remaining oxygen atom is aldehydic or ketonic, for the sugars combine with hydrocyanic acid, hydroxylamine and phenylhydrazine.
It unites with aldehydes to form esters of ketonic acids, and with aniline yields anilido-acetic acid.
It also acts in an opposite manner in certain cases, adding the elements of water to compounds; thus, nitriles are converted into acid-amides, and various acetylene derivatives may be caused to yield ketonic derivatives.
Pseudopelletierine (methyl granatonine), C9H15N0, an alkaloid of the pomegranate, is a derivative of cyclo-octane, and resembles tropine in that it contains a nitrogen bridge between two carbon atoms. It is an inactive base, and also has ketonic properties.