Chapter 16, Problem 16.37P

Draw the structure of each compound.

a. $\left(Z\right)-\text{penta}-1,3-\text{diene}$ in the $s-\text{trans}$ conformation.

b. $\left(2E,4Z\right)-1-\text{bromo}-3-\text{methylhexa}-2,4-\text{diene}$

c. $\left(2E,4E,6Z\right)-\text{octa}-2,4,6-\text{triene}$

d. $\left(2E,4E\right)-3-\text{methylhexa}-2,4-\text{diene}$ in the $s-\text{cis}$ conformation.

Interpretation Introduction

(a)

Interpretation: The structure corresponding to $\left(Z\right)-\text{penta}-1,3-\text{diene}$ in the $\text{s}-\text{trans}$ conformation is to be drawn.

Concept introduction: The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done such that the structure of organic compound is correctly interpreted from the name.

Rules for writing structural formula from IUPAC are:

1. First identify the word root for the given compound.

2. The suffix used in the compound like –ene.

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

The prefix $E$ and $Z$ depends upon the location of the higher priority groups. When two higher priority groups are present on the opposite side then it is an $E$ isomer, whereas when two higher priority groups are present on the same side then it is $Z$ isomer.

Answer to Problem 16.37P

The structure corresponding to $\left(Z\right)-\text{penta}-1,3-\text{diene}$ in the $\text{s}-\text{trans}$ conformation is,

Explanation of Solution

The given name is $\left(Z\right)-\text{penta}-1,3-\text{diene}$. The word root used in this is pent. It means structure contains five carbon atoms. The hydrocarbons that are attached to the longest chain are called substituents and they are written as prefix in alphabetical order. The prefix used is $Z$. It means that two higher priority groups are present on the same side. The given compound has trans conformation. Thus, the correct structure of $\left(Z\right)-\text{penta}-1,3-\text{diene}$ is shown below.

Figure 1

Conclusion

The structure corresponding to $\left(Z\right)-\text{penta}-1,3-\text{diene}$ in the $\text{s}-\text{trans}$ conformation is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation: The structure corresponding to $\left(2E,4Z\right)-1-\text{bromo}-3-\text{methylhexa}-2,4-\text{diene}$ is to be drawn.

Concept introduction: The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done such that the structure of organic compound is correctly interpreted from the name.

Rules for writing structural formula from IUPAC are:

1. First identify the word root for the given compound.

2. The suffix used in the compound like –ene.

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

The prefix $E$ and $Z$ depends upon the location of the higher priority groups. When two higher priority groups are present on the opposite side then it is an $E$ or trans isomer, whereas when two higher priority groups are present on the same side then it is $Z$ or cis isomer.

Answer to Problem 16.37P

The structure corresponding to $\left(2E,4Z\right)-1-\text{bromo}-3-\text{methylhexa}-2,4-\text{diene}$ is,

Explanation of Solution

The given name is $\left(2E,4Z\right)-1-\text{bromo}-3-\text{methylhexa}-2,4-\text{diene}$. The word root used in this is hex. It means structure contains six carbon atoms. The hydrocarbons that are attached to the longest chain are called substituents and they are written as prefix in alphabetical order. The prefix used are $E$ and $Z$. Thus, it means that the stereochemistry at one double bond is trans and at other is cis.

Thus, the correct structure of $\left(2E,4Z\right)-1-\text{bromo}-3-\text{methylhexa}-2,4-\text{diene}$ is shown below.

Figure 2

Conclusion

The structure corresponding to $\left(2E,4Z\right)-1-\text{bromo}-3-\text{methylhexa}-2,4-\text{diene}$ is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation: The structure corresponding to $\left(2E,4E,6Z\right)-\text{octa}-2,4,6-\text{triene}$ is to be drawn.

Concept introduction: The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done such that the structure of organic compound is correctly interpreted from the name.

Rules for writing structural formula from IUPAC are:

1. First identify the word root for the given compound.

2. The suffix used in the compound like –ene.

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

The prefix $E$ and $Z$ depends upon the location of the higher priority groups. When two higher priority groups are present on the opposite side then it is an $E$ isomer, whereas when two higher priority groups are present on the same side then it is $Z$ isomer.

Answer to Problem 16.37P

The structure corresponding to $\left(2E,4E,6Z\right)-\text{octa}-2,4,6-\text{triene}$ is,

Explanation of Solution

The given name is $\left(2E,4E,6Z\right)-\text{octa}-2,4,6-\text{triene}$. The word root used in this is dec. It means structure contains ten carbon atoms. The hydrocarbons that are attached to the longest chain are called substituents and they are written as prefix in alphabetical order. The prefix used is $Z$. It means that two higher priority groups are present on the same side. Thus, the correct structure to $\left(2E,4E,6Z\right)-\text{octa}-2,4,6-\text{triene}$ is shown below.

Figure 3

Conclusion

The structure corresponding to $\left(2E,4E,6Z\right)-\text{octa}-2,4,6-\text{triene}$ is shown in Figure 3.

Interpretation Introduction

(d)

Interpretation: The structure corresponding to $\left(2E,4E\right)-3-\text{methylhexa}-2,4-\text{diene}$ $\text{s}-\text{cis}$ is to be drawn.

Concept introduction: The systematic naming of organic compound is given by IUPAC. The naming of organic compound is done such that the structure of organic compound is correctly interpreted from the name.

Rules for writing structural formula from IUPAC are:

4. First identify the word root for the given compound.

5. The suffix used in the compound like –ene.

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

The prefix $E$ and $Z$ depends upon the location of the higher priority groups. When two higher priority groups are present on the opposite side then it is an $E$ isomer, whereas when two higher priority groups are present on the same side then it is $Z$ isomer.

Answer to Problem 16.37P

The structure corresponding to $\left(2E,4E\right)-3-\text{methylhexa}-2,4-\text{diene}$ in $\text{s}-\text{cis}$ is,

Explanation of Solution

The given name is $\left(2E,4E\right)-3-\text{methylhexa}-2,4-\text{diene}$. The word root used in this is hex. It means structure contains six 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 prefix used is $E$. It means that two higher priority groups are present on the opposite side. Thus, the correct structure to $\left(2E,4E\right)-3-\text{methylhexa}-2,4-\text{diene}$ is shown below.

Figure 4

Conclusion

The structure corresponding to $\left(2E,4E\right)-3-\text{methylhexa}-2,4-\text{diene}$ in $\text{s}-\text{cis}$ is shown in Figure 4.