Question

Draw structures corresponding to the following names: (a) Octylamine (b) \(N\) -Methylpentylamine (c) \(N\) -Ethylaniline (d) 4-Aminobutan-2-ol

Short answer

Draw each compound based on its structural components according to its IUPAC name.

Step-by-step solution

Understanding the Structure of Octylamine

Octylamine is a primary amine with the chemical formula \( C_8H_{19}N \). The octyl group denotes an eight-carbon chain, and the amine group \(-NH_2\) is attached to the first carbon. Draw a straight chain of eight carbon atoms and attach an \( NH_2 \) group to the first carbon atom.

Drawing N-Methylpentylamine

N-Methylpentylamine is a secondary amine where a methyl group \(-CH_3\) is attached to the nitrogen atom of pentylamine. Draw a five-carbon straight chain known as the pentyl group \( C_5H_{11} \) and attach the \( NH \) group to the first carbon. Then attach a methyl group to the nitrogen atom.

Constructing N-Ethylaniline

N-Ethylaniline is an aromatic amine with a phenyl group \( C_6H_5 \) attached to the nitrogen of the amine. Here, an ethyl group \(-C_2H_5\) is attached to the nitrogen atom of aniline. Draw a benzene ring, connect a \( NH \) group, and attach an ethyl group to the nitrogen atom.

Creating the Structure of 4-Aminobutan-2-ol

4-Aminobutan-2-ol is a compound with both an alcohol \(-OH\) and amine \(-NH_2\) groups. Construct a four-carbon chain (butane) as the backbone. Place the \(-NH_2\) group on the fourth carbon, and the \(-OH\) group on the second carbon of the chain.

Key concepts

Amine Compounds

Amine compounds are an essential part of organic chemistry, featuring nitrogen atoms bonded to carbon or hydrogen. These compounds can be classified based on the number of carbon-containing groups (alkyl or aryl) attached to the nitrogen atom. Broadly, they are categorized into:

• Primary amines: where the nitrogen atom is attached to one carbon group, such as octylamine (\(C_8H_{19}N\) and an \(-NH_2\) group).
• Secondary amines: here, the nitrogen is bonded to two carbon groups, like \(N\)-methylpentylamine, where a methyl group is connected to the nitrogen.
• Tertiary amines: when three carbon-containing groups are attached to the nitrogen.

Amine compounds are known for their basic properties due to the lone pair of electrons on nitrogen, making them likely to participate in hydrogen bonding, which influences their solubility and boiling points.

Structural Isomerism

Structural isomerism occurs when molecules have the same molecular formula but different structural formulas. This means that the arrangement of atoms changes, introducing diversity in chemical properties and activities.
In the case of amines and similar compounds, structural isomerism can occur in several ways:

• Chain isomerism: differences in the carbon chain arrangement, such as varying lengths or branches.
• Position isomerism: the functional group changes its position within the carbon skeleton, like moving an \(-NH_2\) group along a carbon chain.
• Functional isomerism: variation in the position of the double bonds or cyclic structures leading to different functional groups.

Structural isomers are crucial to understand because they often exhibit distinct physical and chemical properties, affecting how they interact in biological systems and industrial applications.

Functional Groups

Functional groups are specific groups of atoms within molecules that determine the chemical reactions of those molecules. They are the 'active sites' that often dictate the reactivity and properties of the entire compound. For example:

• The amine group (\(-NH_2\)) makes compounds basic and increases solubility in water due to its ability to form hydrogen bonds.
• Alcohol groups (\(-OH\)) introduce hydrophilic properties, generally making compounds more soluble in water and capable of engaging in hydrogen bonding.
• Aromatic groups, like the phenyl group in \(N\)-ethylaniline, enhance stability and often introduce unique electronic characteristics due to delocalized \(\pi\)-electrons.

Understanding functional groups is vital to predict chemical behavior, helping in designing and synthesizing new organic compounds with desired properties.

Chemical Nomenclature

The nomenclature of organic compounds is a systematic way of naming chemical substances. It allows chemists to communicate unambiguously. Here are some key aspects of naming compounds like those in the exercise:

• The root name denotes the longest carbon chain, such as 'octyl' in octylamine for an eight-carbon chain.
• Prefixes and suffixes specify the functional groups or substituents: \(N\)-methyl indicates a methyl group attached to the nitrogen.
• Numbering the chain with lowest possible numbers for substitutes, such as '4-aminobutan-2-ol', where '4' and '2' indicate positions of \(-NH_2\) and \(-OH\) groups respectively.
• IUPAC rules ensure clarity, selecting the most informative combination of chain, functional group, and substituent names.

Utilizing proper chemical nomenclature is crucial for ensuring precise understanding and avoiding confusion in both academic and practical chemical contexts.