Question

Propose structures for molecules that fit the following descriptions: (a) An amide with the formula \(\mathrm{C}_{4} \mathrm{H}_{9} \mathrm{NO}\) (b) An aldehyde that has a ring of carbons, \(\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}\) (c) An aromatic compound that is also an ether, \(\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{O}\)

Short answer

(a) Propanamide (CH₃CH₂CH₂CONH₂), (b) Cyclohexanecarbaldehyde, (c) Phenethyl methyl ether.

Step-by-step solution

Understanding the Amide Structure

Amides have a general form of \( \text{RCONR'}_2 \), with \( \text{R} \) and \( \text{R'} \) as alkyl or aryl groups. We need to fit the formula \( \text{C}_4\text{H}_9\text{NO} \). Let's create an amide with a butyl group (4 carbons) and attach it to a primary amine group. A simple solution is propanamide (\( \text{CH}_3\text{CH}_2\text{CH}_2\text{CONH}_2 \)).

Understanding the Aldehyde Structure

Aldehydes have the functional group \( \text{CHO} \). We are looking for a cyclic structure with 6 carbons. Cyclohexanecarbaldehyde (\( \text{C}_6\text{H}_{11}\text{CHO} \) - since the aldehyde carbon is typically included in the formula giving total 7 carbons, let's rearrange the formula \( \text{C}_6\text{H}_{10}\text{O} \) such that one carbon is part of the ring structure).

Understanding the Aromatic Ether Structure

Ethers generally have the formula \( \text{R}-\text{O}-\text{R} \) and aromatic ethers contain an aromatic ring. A suitable form of \( \text{C}_8\text{H}_{10}\text{O} \) is phenethyl methyl ether (\( \text{C}_6\text{H}_5\text{CH}_2\text{OCH}_3 \)), containing a benzene ring separated by an oxygen atom connected to another carbon chain.

Key concepts

Amide Structure

Amides are a fascinating group in organic chemistry. They consist of a carbonyl group (\( \text{C}=\text{O} \)) bound to a nitrogen atom, forming the core structure of amides. The general formula can be written as \( \text{RCONR'}_2 \). Here, "R" and "R'" represent organic substituents that can vary. Amides are crucial in biological molecules such as proteins, as they form peptide bonds between amino acids. For the specific formula \( \text{C}_4\text{H}_9\text{NO} \), you may create a compound with a butyl group (containing four carbon atoms) and connect it with an amine group. A simple example is propanamide \( \text{CH}_3\text{CH}_2\text{CH}_2\text{CONH}_2 \). This structure includes a carbon backbone with the amide linkage, which is key to its properties.
Understanding the flexibility of amide structures is beneficial for recognizing their roles in synthetic and biological chemistry.

Aldehyde Structure

Aldehydes are characterized by the presence of the functional group \( \text{CHO} \). This group is essential as it provides the reactive center for transformations in aldehyde chemistry. In cyclic aldehydes, it's crucial to integrate the aldehyde group into a carbon-containing ring. For instance, if we consider a molecule with the formula \( \text{C}_6\text{H}_{10}\text{O} \), a fitting structure would be cyclohexanecarbaldehyde. It features a six-carbon ring with the aldehyde group providing additional reactivity. Keep in mind that aldehydes are versatile due to their partial positive carbon, attributed to the double-bonded oxygen.
This unique arrangement allows aldehydes to participate in various organic reactions like oxidation or nucleophilic addition.

Aromatic Ether

Aromatic ethers are interesting as they combine ether linkages with aromatic rings. An ether typically has two organic groups connected through an oxygen atom, represented as \( \text{R}-\text{O}-\text{R} \). The aromatic nature comes from a benzene or other stable ring structure. An example, following the formula \( \text{C}_8\text{H}_{10}\text{O} \), is phenethyl methyl ether. This compound includes a benzene ring (aromatic) linked by an oxygen, and a methyl group across the ether bridge.
Aromatic ethers often have significant applications in fragrances, sweeteners, and solvents. Their stability and electron-rich aromatic ring modify the chemical behavior compared to aliphatic ethers, making them notable in various industrial applications.