Amide Formation: Videos & Practice Problems

Amide formation is a type of condensation reaction where a carboxylic acid and an amine combine, resulting in the loss of water and the creation of an amide. In the process, the carboxylic acid's hydroxyl group (OH) and one hydrogen from the amine are removed to form water. This reaction requires an H⁺ catalyst to initiate. The remaining carboxylic acid and amine bond together, with the carbon from the carboxylic acid and the nitrogen from the amine forming a new bond. The resulting amide structure features a carbonyl group (C=O) single-bonded to a nitrogen. This reaction is essential in organic chemistry for synthesizing amides, which are common in various organic compounds and biological molecules.

Amide Formation

Amide formation is a significant chemical reaction where a carboxylic acid reacts with an amine through a condensation process to produce an amide. In this reaction, water is eliminated, which is characteristic of condensation reactions. Specifically, the hydroxyl group (–OH) from the carboxylic acid and one hydrogen atom from the amine's nitrogen are removed, resulting in the formation of water (H₂O).

For the reaction to proceed, an acid catalyst (H⁺) is required to initiate the process. The general reaction can be represented as follows:

In this equation, RCOOH represents the carboxylic acid, and R'NH₂ represents the amine. The reaction results in the formation of an amide (RCONHR') and the release of water. The amide structure features a carbonyl group (C=O) bonded to a nitrogen atom (N), which is a defining characteristic of amides.

Overall, the formation of an amide through this condensation reaction highlights the importance of both the carboxylic acid and the amine, as well as the role of the acid catalyst in facilitating the reaction.

Amide Formation Example

When 4-methylpentanoic acid reacts with butylamine, an amide product is formed through a condensation reaction. In this process, the hydroxyl group (–OH) from the carboxylic acid and a hydrogen atom (–H) from the amine are eliminated, resulting in the formation of an amide bond.

The structure of 4-methylpentanoic acid can be represented as follows:

In the reaction, the carbonyl group (C=O) of the acid combines with the nitrogen atom (N) of the amine, leading to the formation of the amide linkage. The nitrogen atom loses one hydrogen atom but retains another, which remains attached to the butyl chain. The resulting amide product can be depicted as:

Thus, the final structure of the amide product from the reaction of 4-methylpentanoic acid and butylamine features a carbonyl group bonded to a nitrogen atom, which is also connected to the butyl group. This illustrates the transformation of the carboxylic acid and amine into an amide through a condensation reaction.

Predict the amide product formed when 2,2-dimethylpropanoic acid reacts with dimethylamine.

• A.
• B.
• C.
• D.

Answer: (B)

Here’s what students ask on this topic:

Which of the following reactions leads to the formation of an amide?

The formation of an amide typically occurs through a reaction known as the acyl substitution reaction. In this process, an acyl group (derived from an acid) reacts with a nitrogen-containing compound such as an amine. One of the most common ways to form an amide is by reacting a carboxylic acid with an amine. The general equation for this reaction is:

$R-{\mathrm{COOH}}_{\text{(carboxylic acid)}}+{\mathrm{R\text{'}}}_{-}\to R_{-}+H_2$

Another common method is the reaction of an acid chloride with an amine:

$R-{\mathrm{COCl}}_{\text{(acid chloride)}}+{\mathrm{R\text{'}}}_{-}\to R_{-}+{\mathrm{HCl}}_{\text{(hydrochloric acid)}}$

Both of these reactions involve the nucleophilic attack of the nitrogen atom on the carbon atom of the carbonyl group, followed by the elimination of a leaving group (water in the case of carboxylic acids, and HCl in the case of acid chlorides), leading to the formation of an amide bond.

Which of the following reactions does not yield an amine?

To determine which reaction does not yield an amine, we need to consider typical reactions that produce amines and those that do not. Common reactions that yield amines include the reduction of nitro compounds, reductive amination, the Gabriel synthesis, and the alkylation of ammonia or an amine.

A reaction that does not yield an amine would be one that either doesn't involve nitrogen-containing starting materials or does not result in the formation of a C-N bond. For example, the SN₂ reaction of an alkyl halide with a hydroxide ion would yield an alcohol rather than an amine. Similarly, the oxidation of an alcohol does not produce an amine; it typically leads to the formation of an aldehyde or a ketone. The hydration of an alkyne also does not yield an amine; instead, it produces an aldehyde or a ketone, depending on the specific conditions and the structure of the alkyne.