Alkylation of an amide via an amine:
Hence, primary amines are transformed to secondary amines and secondary amines are transformed to tertiary amine. The reaction is as well appropriate for the synthesis of primary amines if ammonia is employed in place of an alkylamine. The reaction undergoes an imine intermediate if ammonia or a primary amine is employed. While a secondary amine is employed, an iminium ion intermediate is involved.
Another way of alkylating an amine is to acylate the amine to provide an amide and then perform a reduction with LiAlH4. Even though two steps are involved, there is no risk of over-alkylation since acylation can only take place once.
Figure: Alkylation of an amide via an amine.