Chapter 5, Problem 19P

Write structural formulas for each of the following alcohols and alkyl halides:

(a) $Cyclobutanol$

(e) $2,6-Dichloro-4-methyl-4-octanol$

(b) $sec-Butylalcohol$

(f) $trans-4-ter-Butylcyclohexanol$

(c) $3-Heptanol$

(g) $1-Cyclopropylethanol$

(d) $trans-2-Chlorocyclopentanol$

(h) $2-Cyclopropylethanol$

Interpretation Introduction

Interpretation:

The structural formulas for the given alcohols and alkyl halides are to be written.

Concept introduction:

While making the structure of an alcohol, the name of the parent alcohol is used to determine the number of atoms in the parent chain.

The substituents attached and their positions on the parent chain are determined from the name and these are drawn accordingly.

Solid lines are used to show the covalent bonds between atoms.

The structural formula of a compound shows how the atoms are arranged and bonded to each other in the compound.

Answer to Problem 19P

Solution:

$\text{Cyclobutanol}$

$\begin{array}{l}\text{sec-Butyl alcohol}\hfill \end{array}$

$\begin{array}{l}\text{3-Heptanol}\hfill \end{array}$

$\begin{array}{l}\text{trans-2-Chlorocyclopentanol}\hfill \end{array}$

$\begin{array}{l}\text{2,6-Dichloro-4-methyl-4-octanol}\hfill \end{array}$

$\begin{array}{l}\text{trans-4-tert-Butylcyclohexanol}\hfill \end{array}$

$\begin{array}{l}\text{1-Cyclopropylethanol}\hfill \end{array}$

$\begin{array}{l}\text{2-Cyclopropylethanol}\hfill \end{array}$

Explanation of Solution

a) $\text{Cyclobutanol}$

In $\text{cyclobutanol}$, the prefix cyclo indicates that the structure is cyclic. The suffix ‘–ol’ indicates the functional group is alcohol. Cyclobutanol represents a cyclic ring of four carbon atoms with the hydroxyl group attached to one of the carbon atoms of the ring.

Therefore, the structure of $\text{cyclobutanol}$ is as shown below.

b) $\begin{array}{l}\text{sec-Butyl alcohol}\hfill \end{array}$.

In $\begin{array}{l}\text{sec-Butyl alcohol}\hfill \end{array}$, the word ‘butyl’ indicates that there is a $4$ carbon chain. The prefix ‘sec’ and the word alcohol indicates that the functional group, which is alcohol in this case, is attached to the secondary carbon atom on the butane chain.

The structure of $\begin{array}{l}\text{sec-Butyl alcohol}\hfill \end{array}$ is shown as follows.

c) $\begin{array}{l}\text{3-Heptanol}\hfill \end{array}$

In $\begin{array}{l}\text{3-Heptanol}\hfill \end{array}$, the prefix ‘hept-’ indicates that the parent chain has $\text{7}$ carbon atoms. The suffix ‘–ol’ indicates that the functional group is alcohol. The number $3$ indicates that the alcohol group is attached to the third carbon atom of the heptane chain.

Therefore, the structure of $\begin{array}{l}\text{3-Heptanol}\hfill \end{array}$ is drawn as follows.

d) $\begin{array}{l}\text{trans-2-Chlorocyclopentanol}\hfill \end{array}$

In $\begin{array}{l}\text{trans-2-Chlorocyclopentanol}\hfill \end{array}$, ‘cyclopentanol’ indicates that the parent compound is cyclopentane. The prefix ‘chloro’ indicates that the chlorine atom is attached to the parent compound and its position is second carbon atom. The suffix ‘-ol’ indicates that the functional group is alcohol here and it is attached to carbon atom numbered one.

The prefix ‘trans’ indicates that the chlorine and hydroxyl groups are on the opposite sides of the cyclopentane ring.

The structure of $\begin{array}{l}\text{trans-2-Chlorocyclopentanol}\hfill \end{array}$ can be shown as below.

e) $\begin{array}{l}\text{2,6-Dichloro-4-methyl-4-octanol}\hfill \end{array}$.

In $\begin{array}{l}\text{2,6-Dichloro-4-methyl-4-octanol}\hfill \end{array}$, the parent alkane is octane. The hydroxyl group is attached to the fourth carbon atom. One chlorine atom is attached to the second carbon atom while the other chlorine atom is attached to the sixth carbon atom of the octane chain. A methyl group is attached to the fourth carbon atom of the octane chain.

Therefore, the structure of $\begin{array}{l}\text{2,6-Dichloro-4-methyl-4-octanol}\hfill \end{array}$ can be shown as follows.

f) $\begin{array}{l}\text{trans-4-tert-Butylcyclohexanol}\hfill \end{array}$

In $\begin{array}{l}\text{trans-4-tert-Butylcyclohexanol}\hfill \end{array}$, the parent chain is a cyclic hexane ring. The tertiary butyl group is attached to the fourth carbon atom while the hydroxyl group is attached to the first carbon atom. These two groups are trans to each other. In other words, they are on the opposite sides of the cyclohexane ring.

The structure of $\begin{array}{l}\text{trans-4-tert-Butylcyclohexanol}\hfill \end{array}$ is shown below:

g) $\begin{array}{l}\text{1-Cyclopropylethanol}\hfill \end{array}$

In $\begin{array}{l}\text{1-Cyclopropylethanol}\hfill \end{array}$, the parent alkane is ethane. The hydroxyl group is attached to the first carbon atom. The cyclopropyl group is also attached to the first carbon atom of ethane.

The structure of $\begin{array}{l}\text{1-Cyclopropylethanol}\hfill \end{array}$ can be shown as follows.

h) $\begin{array}{l}\text{2-Cyclopropylethanol}\hfill \end{array}$

In $\begin{array}{l}\text{2-Cyclopropylethanol}\hfill \end{array}$, the parent alkane is ethane. The hydroxyl group is attached to the first carbon atom while the cyclopropyl group is attached to the second carbon atom of ethane.

The structure of $\begin{array}{l}\text{2-Cyclopropylethanol}\hfill \end{array}$ is shown below: