Compounds containing the group - CH: O are known as aldehydes (q.v.), while the group >C: O (sometimes termed the carbonyl or keto group) characterizes the ketones (q.v.).
In general, the rupture occurs between a keto group (CO) and a keto-chloride group (CC1 2), into which two adjacent carbon atoms of the ring are converted by the oxidizing and substituting action of chlorine.
It is found also that some monosaccharoses behave as aldehydes whilst others contain a keto group; those having the first character are called aldoses, and the others ketoses.
Those in which the keto groups are in combination with phenyl residues give pyridine derivatives on treatment with hydroxylamine, thus benzamarone, C 6 H 5 CH[CH(C 6 H 5) CO.
On oxidation .ith chromic acid it forms a quinone, C 15 H 8 0 2, and an a-diphenylene keto carboxylic acid C E I-4 3.