|| Chapter 17: Aldehydes
and Ketones. Nucleophilic Addition to C=O
Reactions of Primary
Reaction type: Nucleophilic
Addition then Elimination
- Aldehydes and ketones react with
a range of primary amine derivatives to give substituted imines.
- The derivatives with ammonia
are too unstable to be isolated but can be reduced in situ to amines.
- The mechanism of these type of
reactions is shown on the previous page.
- The reaction of 2,4-dinitrophenylhydrazone
(2,4-DNP or Brady's reagent) is used as a laboratory test for aldehydes and
ketones since the products precipitate as yellow to red solids.
Yellow to red precipitate
indicates a positive test result
Ian Hunt, Department
of Chemistry, University of Calgary