Amides are formed by the reaction of carboxylic acids with ammonia, primary and secondary amines. The reaction is carried out under heating.
At low temperatures, amines react with carboxylic acids as bases and not as nucleophiles.
![synthesis-amides sintesis-amidas](/images/stories/organica-ii/acidos-carboxilicos/sintesis-amidas/sintesis-amidas-01.png)
This acid-base reaction is impaired when heated, predominating under these conditions the nucleophilic attack that will form the amide.
![synthesis-amides sintesis-amidas](/images/stories/organica-ii/acidos-carboxilicos/sintesis-amidas/sintesis-amidas-02.png)
The reaction mechanism occurs in the following stages:
Stage 1. Addition of ammonia to the carboxylic group
![synthesis-amides sintesis-amidas](/images/stories/organica-ii/acidos-carboxilicos/sintesis-amidas/sintesis-amidas-03.png)
![synthesis-amides sintesis-amidas](/images/stories/organica-ii/acidos-carboxilicos/sintesis-amidas/sintesis-amidas-04.png)
Stage 2. Acid-base balance to transform the -OH into a good leaving group
![synthesis-amides sintesis-amidas](/images/stories/organica-ii/acidos-carboxilicos/sintesis-amidas/sintesis-amidas-04.png)
Stage 3. Water removal
![synthesis-amides sintesis-amidas](/images/stories/organica-ii/acidos-carboxilicos/sintesis-amidas/sintesis-amidas-05.png)