Question

Draw structures of four different amides with molecular formula \(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{NO}\).

Short answer

The four different amide structures are: 1. Primary amide: ``` O || C | N - CH2 - CH3 ``` 2. Secondary amide: ``` O || C | H3C - N - CH2 - CH3 ``` 3. Different secondary amide / isoamide: ``` O || CH3 - C | H3C - N - H ``` 4. Tertiary amide: ``` O || C | H3C - N - (CH2 - CH3)2 ```

Step-by-step solution

Draw the basic amide structure

The basic amide structure contains a carbonyl group (C=O) and a nitrogen atom (N) bonded to the carbonyl carbon. It looks like: ``` O || C | N ```

Create the primary amide

A primary amide has one alkyl group attached to the nitrogen atom. In this case, we can distribute the remaining two carbon atoms to form an ethyl group on the nitrogen atom. The primary amide will have the structure: ``` O || C | N - CH2 - CH3 (Primary amide) ```

Create the secondary amide

In a secondary amide, the nitrogen atom has two alkyl or aryl groups attached to it. We can create a secondary amide by having one methyl and one ethyl group attached to the nitrogen atom. The structure would be: ``` O || C | H3C - N - CH2 - CH3 (Secondary amide) ```

Create a different secondary amide

We can create another secondary amide by arranging the carbon atoms in a different way. We can create that by placing a methyl group on the initial carbon, forming an isoamide structure: ``` O || CH3 - C | H3C - N - H (Different secondary amide / isoamide) ```

Create the tertiary amide

Finally, we need to create a tertiary amide, where the nitrogen atom has three alkyl or aryl groups attached to it. In this case, we can have one methyl and two ethyl groups attached to the nitrogen atom. The structure would be: ``` O || C | H3C - N - (CH2 - CH3)2 (Tertiary amide) ``` These are the four different amide structures with the molecular formula \(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{NO}\).

Key concepts

Molecular Formula

Understanding the molecular formula of a compound is essential as it provides us with the exact number of atoms of each element present within the molecule. In the case of amides with the molecular formula \( \mathrm{C}_{3} \mathrm{H}_{7} \mathrm{NO} \), we know that there are three carbon atoms (C), seven hydrogen atoms (H), one nitrogen atom (N), and one oxygen atom (O). This formula serves as the blueprint for constructing various amide structures, defining the types of amides that can be formed from these elements.

When tasked with drawing different amide structures that conform to this formula, one must account for the central features of amides, such as the presence of a carbonyl group (C=O) and a nitrogen atom (N) directly attached to the carbonyl carbon. The remaining atoms are then arranged around these groups to form primary, secondary, or tertiary amides.

Primary Amide

A primary amide is characterized by having a nitrogen atom connected to a single alkyl or aryl group, with the remaining bonds on nitrogen typically being hydrogen atoms. The distinguishing feature of primary amides in the structural formula is that the nitrogen is bonded to only one carbon-containing group.

Take, for example, the solution provided for the primary amide structure within the given molecular formula \( \mathrm{C}_{3} \mathrm{H}_{7} \mathrm{NO} \). By attaching a two-carbon chain (ethyl group) to the nitrogen atom and accounting for hydrogen atoms accordingly, we adhere to the molecular formula while successfully creating a primary amide structure.

Secondary Amide

Moving on to secondary amides, these are defined by the nitrogen atom being bonded to two alkyl or aryl groups. Unlike primary amides, secondary amides do not necessarily have hydrogen atoms attached to the nitrogen, making them distinct in structure.

In the solution steps, two examples of secondary amides were created. The first example joined an ethyl group with a methyl group to the nitrogen, and in the second, an isomer was formed by shifting the methyl group to the carbon in the carbonyl group. These variations demonstrated the flexibility in forming different secondary amides while still respecting the original molecular formula \( \mathrm{C}_{3} \mathrm{H}_{7} \mathrm{NO} \).

Tertiary Amide

Tertiary amides are even more complex, with the nitrogen atom bound to three carbon-containing groups. Therefore, tertiary amides typically do not have any hydrogen atoms directly attached to the nitrogen.

In creating a tertiary amide for the exercise, all available carbon atoms were utilized to attach to the nitrogen atom, resulting in one methyl and two ethyl groups being linked. This arrangement highlights the defining characteristic of tertiary amides and fulfills the requirement set by the molecular formula. Tertiary amides, due to their structure, may exhibit different chemical properties and reactivity compared to primary and secondary amides.

Organic Chemistry

Organic chemistry, the study of carbon-containing compounds, is a broad and essential field in chemistry. Amides are a fundamental class of organic compounds featured prominently within this domain. They represent key structural elements in proteins and are vital in various chemical synthesis processes.

The exercise of drawing amides with a specified molecular formula is a good example of applying organic chemistry concepts. It teaches students how to identify amide functional groups, differentiate between primary, secondary, and tertiary amides, and creatively distribute atoms to satisfy a chemical formula. Mastery of these core concepts is crucial for understanding the diverse and complex nature of organic compounds.