Definition
Ketones are organic compounds containing a carbonyl group (C=O) with two aliphatic or aromatic radicals (R1, R2) attached to its carbon atom. In aldehydes, one of the radicals is a hydrogen atom (H). Ketones can be synthesized, for example, by oxidation of alkoles. The simplest representative is acetone.
Nomenclature
Ketones are usually named with the suffix -on or -ketone. So, for example, pentanone, butan-2-one (ethyl methyl ketone), cyclohexyl phenyl ketone, and dimethyl ketone (= acetone).
Representative
Examples of ketones:
- Acetone
- Acetophenone
- Benzophenone
- Carvone
- Cyclohexanone
- Progesterone
- Testosterone
Properties
- Ketones are hydrogen bond acceptors but not donors. Therefore, the boiling point is lower compared to alkoles.
- Ketones often have an aromatic odor or taste and are also used as flavoring agents.
Reactions
The carbonyl group of ketones is polarized. The oxygen is partially negatively charged and the carbon is partially positively charged. Therefore, ketones can be nucleophilically substituted like the aldehydes. However, the aldehydes are more reactive. Ketones can be reduced with reducing agents to alkools. The carbonyl oxygen is slightly basic and can be protonated. This facilitates nucleophilic attack.
In pharmaceuticals
- As a functional group in numerous active ingredients and in excipients.
- For chemical syntheses.
- As a solvent.
