Amides that are cyclic are called lactams and are named by replacing –oic acid with –lactam. They
may also be named by indicating the specific carbon that is bonded during cyclization of the
compound. Several examples are shown in Figure 8.12.
Figure 8.12. Examples of LactamsEsters
Esters are a hybrid between a carboxylic acid and an ether (ROR′ ), which can be made by reacting
carboxylic acids with alcohols under acidic conditions, as shown in Figure 8.13. Esterification is a
condensation reaction with water as a side product. In acidic solutions, the carbonyl oxygen can be
protonated, which enhances the polarity of the bond, thereby placing additional positive charge on
the carbonyl carbon and increasing its susceptibility to nucleophilic attack. This condensation
reaction occurs most rapidly with primary alcohols.
Figure 8.13. Esterification: Reaction of a Carboxylic Acid with an AlcoholKEY CONCEPT
Protonating the C=O makes the electrophilic carbon even more ripe for nucleophilic attack.