Chapter 14, Problem 14.8E

Interpretation Introduction

(a)

Interpretation:

The structural formula of propanal is to be drawn.

Concept introduction:

The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done in such a way that the structure of organic compound is correctly interpreted from the name.

Rules for writing the structural formula from IUPAC are:

• First identify the word root for the given compound.

• The suffix used in the compound like –ane, ene, yne, ol, al and so on.

• Identify the position, location, and number of the substituent bonded to the carbon chain.

Aldehydes and ketones contain carbonyl functional group in their parent chain and are named by adding suffix –al and –one to the name of the parent alkane.

Answer to Problem 14.8E

The structural formula of propanal is,

Explanation of Solution

The given name is propanal. The functional group present in the given compound is aldehyde $\left(\text{CHO}\right)$. The suffix used for aldehyde is –al. The base name of the compound is propane. Therefore, the structure contains three carbon atoms and aldehyde group is directly attached to the first carbon atom. Therefore, the structural formula of propanal is shown below.

Figure 1

Conclusion

The structural formula of propanal is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The structural formula of $\text{3-methyl-2-butanone}$ is to be drawn.

Concept introduction:

The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done in such a way that the structure of organic compound is correctly interpreted from the name.

Rules for writing the structural formula from IUPAC are:

• First identify the word root for the given compound.

• The suffix used in the compound like –ane, ene, yne, ol, al and so on.

• Identify the position, location, and number of the substituent bonded to the carbon chain.

Aldehydes and ketones contain carbonyl functional group in their parent chain and are named by adding suffix –al and –one to the name of the parent alkane.

Answer to Problem 14.8E

The structural formula of $\text{3-methyl-2-butanone}$ is,

Explanation of Solution

The given name is $\text{3-methyl-2-butanone}$. The root word used in this is but. It means structure contains four carbon atoms. The hydrocarbons that are attached to the longest chain are called substituents and they are written as prefix in alphabetical order. One methyl substituent is attached to the third carbon atom. The functional group present in the given compound is ketone $\left(\text{R-CO-R}\right)$ because the suffix used for ketone is –one. It is present at second carbon atom. Therefore, the structure corresponding to $\text{3-methyl-2-butanone}$ is shown below.

Figure 2

Conclusion

The structural formula of $\text{3-methyl-2-butanone}$ is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation:

The structural formula of $\text{2, 2-dimethylcyclopentanone}$ is to be drawn.

Concept introduction:

The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done in such a way that the structure of organic compound is correctly interpreted from the name.

Rules for writing the structural formula from IUPAC are:

• First identify the word root for the given compound.

• The suffix used in the compound like –ane, ene, yne, ol, al and so on.

• Identify the position, location, and number of the substituent bonded to the carbon chain.

Aldehydes and ketones contain carbonyl functional group in their parent chain and are named by adding suffix –al and –one to the name of the parent alkane.

Answer to Problem 14.8E

The structural formula of $\text{2, 2-dimethylcyclopentanone}$ is,

Explanation of Solution

The given name is $\text{2, 2-dimethylcyclopentanone}$. The root word used in this is cyclopent. It means structure contains five carbon atoms in a ring. Two methyl groups are attached to the second carbon atom. The functional group present in the given compound is ketone $\left(\text{R-CO-R}\right)$ because the suffix used for ketone is –one. It is present at first carbon atom. Therefore, the structure corresponding to $\text{2, 2-dimethylcyclopentanone}$ is shown below.

Figure 3

Conclusion

The structural formula of $\text{2, 2-dimethylcyclopentanone}$ is shown in Figure 3.

Interpretation Introduction

(d)

Interpretation:

The structural formula of $\text{3-bromo-4-phenylbutanal}$ is to be drawn.

Concept introduction:

The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done in such a way that the structure of organic compound is correctly interpreted from the name.

Rules for writing the structural formula from IUPAC are:

• First identify the word root for the given compound.

• The suffix used in the compound like –ane, ene, yne, ol, al and so on.

• Identify the position, location, and number of the substituent bonded to the carbon chain.

Aldehydes and ketones contain carbonyl functional group in their parent chain and are named by adding suffix –al and –one to the name of the parent alkane.

Answer to Problem 14.8E

The structural formula of $\text{3-bromo-4-phenylbutanal}$ is,

Explanation of Solution

The given name is $\text{3-bromo-4-phenylbutanal}$. The root word used in this is but. It means structure contains four carbon atoms. One bromo group is attached to the third carbon atom and one phenyl group is attached to the fourth carbon atom. The functional group present in the given compound is aldehyde $\left(\text{COH}\right)$ because the suffix used for aldehyde is –al. It is present at first carbon atom. Therefore, the structure corresponding to $\text{3-bromo-4-phenylbutanal}$ is shown below.

Figure 4

Conclusion

The structural formula of $\text{3-bromo-4-phenylbutanal}$ is shown in Figure 4.