Functional Classes II, Reactions - Organic Chemistry Concepts: An EFL Approach - page 127

FIGURE 7.44
Hydride reduction of acyl derivatives.
7.9 AMINES
Chapter 6 examined the structure and Lewis basicity of amines. The chemistry
of amines is mostly about the nitrogen lone pair and its nucleophilic or basic
properties. Therefore, amine reactions are based on either nucleophilic substitu-
tion or acid-base types. Common substrates for nucleophilic substitution are
alkyl and acyl halides. Reaction of these substrates gives alkylation and acylation
products.
7.9.1 Alkylation
Amines are derivatives of ammonia. They are prepared by replacement of the
hydrogens of NH 3 with carbon groups. Figure 7.45 shows ammonia and amines
reacting as non-ionic nucleophiles in S N 2 type reactions with alkyl halides.
These alkylation reactions add alkyl groups and give higher order amines.
Positive inductive effects from alkyl groups cause an amine to become more
nucleophilic, as it has more alkyl groups attached to it. In fact, it can be very dif-
ficult to stop the process at any point during alkylation. Because of this lack of
control, mixtures of products are usually formed.
FIGURE 7.45
Stepwise amine alkylation.