MCAT EXPERTISE
While you may have learned about other acyl derivatives in your organic chemistry classes,
such as acyl halides and nitriles, the official content list for the MCAT restricts its focus to
carboxylic acids, amides, esters, and anhydrides.Amides
Carboxylic acids can be converted into amides if the incoming nucleophile is ammonia (NH 3 ) or an
amine, as shown in Figure 8.10. This can be carried out in either an acidic or basic solution to drive
the reaction forward.
Figure 8.10. Formation of an Amide by Nucleophilic Acyl SubstitutionAmides are named by replacing the –oic acid suffix with –amide in the name of the parent
carboxylic acid. Any alkyl groups on the nitrogen are placed at the beginning of the name with the
prefix N–. Amides exist in a resonance state where delocalization of electrons occurs between the
oxygen and nitrogen atoms, as shown in Figure 8.11.
Figure 8.11. Resonance of Amides
Resonance between the carbonyl and lone pair on the nitrogen stabilizes this bond and restricts its
motion.