Chapter A, Problem A.30P

Interpretation Introduction

(a)

Interpretation:

The IUPAC name for the structure is to be given.

Concept introduction:

In the IUPAC nomenclature, the longest continuous carbon chain or the largest carbon ring is considered as the parent chain. The name of this corresponding parent chain/ring will be the root of the molecule’s name. Identify the substituents and add the name of the substituent as a prefix to the left of the root. The number assigned to the carbon that is bonded to the substituent is called the locator number or locant. In case of two or more different substituents, the alphabetical order is considered. Number each carbon atom of the chain sequentially, beginning with $\text{C1}$, so that the carbon atom to which the substituent is bonded receives the lowest possible number. The numbering continues either clockwise or anticlockwise, depending on the second substituent encountered, if any. The second substituent should receive the lower possible locator number. The locator number is written to the left of the substituent’s name, and a hyphen is added to separate the locator number from the rest of the name.

Answer to Problem A.30P

The correct IUPAC name for the structure is $\text{1, 1, 2-trimethylcyclopentane}$.

Explanation of Solution

The given structure is

In the structure above, the ring has more carbon atoms than any of the straight chain groups. Hence, the root name of this structure is “cyclopentane.” The carbon atom of this ring, which is attached to two methyl groups, will be numbered as $\text{C1}$. The numbering will continue clockwise as the second substituent should receive the next possible lowest number. Since the methyl substituent appears three times, the prefix “tri” is added in the name. Thus, the correct IUPAC name for the structure is $\text{1, 1, 2-trimethylcyclopentane}$.

Conclusion

The correct IUPAC name for the given structure is $\text{1, 1, 2-trimethylcyclopentane}$.

Interpretation Introduction

(b)

Interpretation:

The IUPAC name for the structure is to be given.

Concept introduction:

In the IUPAC nomenclature, the longest continuous carbon chain or the largest carbon ring is considered as the parent chain. The name of this corresponding parent chain/ring will be the root of the molecule’s name. Identify the substituents and add the name of the substituent as a prefix to the left of the root. The number assigned to the carbon that is bonded to the substituent is called the locator number or locant. In case of two or more different substituents, the alphabetical order is considered. Number each carbon atom of the chain sequentially, beginning with $\text{C1}$, so that the carbon atom to which the substituent is bonded receives the lowest possible number. The numbering continues either clockwise or anticlockwise, depending on the second substituent encountered, if any. The second substituent should receive the lower possible locator number. The locator number is written to the left of the substituent’s name, and a hyphen is added to separate the locator number from the rest of the name.

Answer to Problem A.30P

The correct IUPAC name for the structure is $\text{1, 2-diethyl-1-methylcyclobutane}$.

Explanation of Solution

The given structure is

In the above structure, the ring has more carbon atoms than any of the straight chain groups. Hence, the root name of this structure is “cyclobutane.” The carbon atom of this ring, which is attached to two substituents, will be numbered as $\text{C1}$. The numbering will continue clockwise as the second substituent should receive the next possible lowest locator number. There are two types of substituents present, methyl and ethyl. Two ethyl substituents are attached to the $\text{C1 and C2}$ carbon atoms while a methyl substituent is attached to the $\text{C1}$ carbon atom of cyclobutane. The prefix “di” is added to indicate two ethyl substituents. Out of the two substituents, methyl and ethyl, ethyl comes first alphabetically. Thus, it should be written first in the IUPAC name. Thus, the correct IUPAC name for the structure is $\text{1, 2-diethyl-1-methylcyclobutane}$.

Conclusion

The correct IUPAC name for the given structure is $\text{1, 2-diethyl-1-methylcyclobutane}$.

Interpretation Introduction

(c)

Interpretation:

The IUPAC name for the structure is to be given.

Concept introduction:

In the IUPAC nomenclature, the longest continuous carbon chain or the largest carbon ring is considered as the parent chain. The name of this corresponding parent chain/ring will be the root of the molecule’s name. Identify the substituents and add the name of the substituent as a prefix to the left of the root. The number assigned to the carbon that is bonded to the substituent is called the locator number or locant. In case of two or more different substituents, the alphabetical order is considered. Number each carbon atom of the chain sequentially, beginning with $\text{C1}$, so that the carbon atom to which the substituent is bonded receives the lowest possible number. The numbering continues either clockwise or anticlockwise, depending on the second substituent encountered, if any. The second substituent should receive the lower possible locator number. The locator number is written to the left of the substituent’s name, and a hyphen is added to separate the locator number from the rest of the name.

Answer to Problem A.30P

The correct IUPAC name for the structure is $\text{cyclobutylcyclopentane}$.

Explanation of Solution

The given structure is

In the structure above, two rings are present. The ring on the left has more number of carbon atoms than the ring on the right; hence the root name of this compound is “cyclopentane.” The carbon atom of this cyclopentane ring to which the cyclobutane ring is attached will be numbered as $\text{C1}$. The parent ring having only one substituent ring. Thus, the correct IUPAC name for the structure is $\text{cyclobutylcyclopentane}$.

Conclusion

The correct IUPAC name for the given structure is $\text{cyclobutylcyclopentane}$.

Interpretation Introduction

(d)

Interpretation:

The IUPAC name for the structure is to be given.

Concept introduction:

In the IUPAC nomenclature, the longest continuous carbon chain or the largest carbon ring is considered as the parent chain. The name of this corresponding parent chain/ring will be the root of the molecule’s name. Identify the substituents and add the name of the substituent as a prefix to the left of the root. The number assigned to the carbon that is bonded to the substituent is called the locator number or locant. In case of two or more different substituents, the alphabetical order is considered. Number each carbon atom of the chain sequentially, beginning with $\text{C1}$, so that the carbon atom to which the substituent is bonded receives the lowest possible number. The numbering continues either clockwise or anticlockwise, depending on the second substituent encountered, if any. The second substituent should receive the lower possible locator number. The locator number is written to the left of the substituent’s name, and a hyphen is added to separate the locator number from the rest of the name.

Answer to Problem A.30P

The correct IUPAC name for the structure is $\text{3-cyclobutyl-2-cyclopropylpentane}$.

Explanation of Solution

The given structure is

In the structure above, there are two rings and a straight chain of carbon atoms. Out of these, the straight continuous carbon chain has more atoms than any of the rings. Hence, the straight chain carbon will serve as the parent, and the two rings will serve as substituents. Thus, the root name of this structure is “pentane.” The numbering of this parent chain should start from the left as the substituent encountered receives the lowest possible locator number. The two substituents are attached on the $\text{C2 and C3}$ carbon atoms of the parent chain, pentane. Since the two substituents are rings, the prefix “cyclo” is added while naming. The two substituents are cyclopropyl and cyclobutyl. Cyclobutyl will be written first as butyl comes first alphabetically. Thus, the IUPAC name for this structure is $\text{3-cyclobutyl-2-cyclopropylpentane}$.

Conclusion

The correct IUPAC name for the given structure is $\text{3-cyclobutyl-2-cyclopropylpentane}$.

Interpretation Introduction

(e)

Interpretation:

The IUPAC name for the structure is to be given.

Concept introduction:

In the IUPAC nomenclature, the longest continuous carbon chain or the largest carbon ring is considered as the parent chain. The name of this corresponding parent chain/ring will be the root of the molecule’s name. Identify the substituents and add the name of the substituent as a prefix to the left of the root. The number assigned to the carbon that is bonded to the substituent is called the locator number or locant. In case of two or more different substituents, the alphabetical order is considered. Number each carbon atom of the chain sequentially, beginning with $\text{C1}$, so that the carbon atom to which the substituent is bonded receives the lowest possible number. The numbering continues either clockwise or anticlockwise, depending on the second substituent encountered, if any. The second substituent should receive the lower possible locator number. The locator number is written to the left of the substituent’s name, and a hyphen is added to separate the locator number from the rest of the name.

Answer to Problem A.30P

The correct IUPAC name for the structure is $\text{2, 2-dicyclopropyl-3, 3-dimethylbutane}$.

Explanation of Solution

The given structure is

In the structure above, the straight continuous chain of carbon atoms will serve as the parent as it contains the highest number of carbon atoms than the rings. Hence, the root name of this structure is “butane.” There are two types of substituents attached- cyclopropyl and methyl. As the prefix “cyclo” is considered while naming, it will appear first in the IUPAC name. Thus, the numbering will also start from the left so that the carbon atom with two cyclopropyl rings will get the lowest possible locator numbers. The prefix di will be used for both the substituents as they appear twice. Thus, the IUPAC name for this structure is $\text{2, 2-dicyclopropyl-3, 3-dimethylbutane}$.

Conclusion

The correct IUPAC name for the given structure is $\text{2, 2-dicyclopropyl-3, 3-dimethylbutane}$.