Return to Contents  Chapter 17: Aldehydes and Ketones. Nucleophilic Addition to C=O  Ch 17 contents

Reactions of Primary Amines

primary amines give imine derivatives
                                                                      imine
Reaction type:  Nucleophilic Addition then Elimination

Summary

QUESTION Why can't amine nucleophiles be used in strongly acidic media ? ANSWER

Related Reactions

NUCLEOPHILIC ADDITION OF A PRIMARY AMINE GIVING AN IMINE
Step 1:
An acid/base reaction. Protonation of the carbonyl activates it and makes it more susceptible to attack by a neutral nucleophilic like the N of a primary amine.
formation of an imine
Step 2:
Attack of the N nucleophile at the electrophilic C of the C=O group with the electrons from the π bond going to the +ve O.
Step 3:
An acid/base reaction. Removal of the proton neutralises the +ve charge on the N and forms the carbinolamine intermediate.
Step 4:
To form the imine we need to dehydrate. However, before -OH leaves it needs to be protonated, so a simple acid/base reaction.
Step 5:
Use the electrons of the N to help push out the leaving group, a neutral water molecule, forming a C=N in the form of an iminium ion.
Step 6:
An acid/base reaction. Deprotonation of the iminium N reveals the imine product and regenerates the acid catalyst.

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© Dr. Ian Hunt, Department of Chemistry, University of Calgary