Chapter B, Problem B.23P

Interpretation Introduction

(a)

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ‘ane’ by ‘ene’ if a double bond is present. The suffix ‘ane’ is replaced by ‘yne’ if a triple bond is present.

If the root is a chain, numbering begins from that end of the chain which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond at the earliest. If there is a tie, the chain is numbered such that the substituents get the lowest locator numbers.

The carbon atoms having a double or triple bond between them are always assigned C1 and C2, if the root is a ring. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond is written before the ‘ene’ or ‘yne’ suffix. Prefixes and locator numbers are used for the substituents attached.

Answer to Problem B.23P

The IUPAC name for the given compound is:

Explanation of Solution

The given molecule is:

In this molecule, the largest carbon ring containing the double bond has six carbon atoms. Hence, the root is cyclohexene. The ring is numbered such that the double bonded carbon atoms get C1 and C2 as the locator numbers.

The numbering system is shown below:

One methyl group is attached at the C3 carbon atom of the ring.

Thus, the IUPAC name of the compound is: $\text{3-methylcyclohexene}$

Conclusion

The IUPAC name of the compound is written according to the rules for nomenclature.

Interpretation Introduction

(b)

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ane by ene, if a double bond is present. The suffix ane is replaced by yne if a triple bond is present.

If the root is a chain, numbering begins from that end of the chain which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond at the earliest. If there is a tie, the chain is numbered such that the substituents get the lowest locator numbers.

The carbon atoms having a double or triple bond between them are always assigned C1 and C2, if the root is a ring. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond is written before the ene or yne suffix. Prefixes and locator numbers are used for the substituents attached.

Answer to Problem B.23P

The IUPAC name for the given compound is: $\text{3-chlorocyclobutene}$

Explanation of Solution

The given compound is:

In this molecule, the largest carbon ring containing the double bond has four carbon atoms. Hence, the root is cyclobutene. The ring is numbered such that the double bonded carbon atoms get C1 and C2 as the locator numbers.

The numbering system is shown below:

One chlorine atom is attached as a substituent on the C3 carbon atom of the ring.

Thus, the IUPAC name of the compound is: $\text{3-chlorocyclobutene}$.

Conclusion

The IUPAC name of the compound is written according to the rules for nomenclature.

Interpretation Introduction

(c)

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ane by ene, if a double bond is present. The suffix ane is replaced by yne if a triple bond is present.

If the root is a chain, numbering begins from that end of the chain which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond at the earliest. If there is a tie, the chain is numbered such that the substituents get the lowest locator numbers.

The carbon atoms having a double or triple bond between them are always assigned C1 and C2, if the root is a ring. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond is written before the ene or yne suffix. In case of cycloalkene or cycloalkyne, the locator number is not included explicitly. Prefixes and locator numbers are used for the substituents attached.

Answer to Problem B.23P

The IUPAC name for the given compound is: $\text{4, 4-dibromocycloheptene}$

Explanation of Solution

The given molecule is:

In this molecule, the largest carbon ring containing the double bond has seven carbon atoms. Hence, the root is cycloheptene. The ring is numbered such that the double bonded carbon atoms get C1 and C2 as the locator numbers.

The numbering system is shown below:

Two bromine atoms are attached to the C4 carbon atom of the ring. Thus, a prefix ‘di’ must be used to indicate the number of bromide substituents.

Thus, the IUPAC name of the compound is: $\text{4, 4-dibromocycloheptene}$.

Conclusion

The IUPAC name of the compound is written according to the rules for nomenclature.

Interpretation Introduction

(d)

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ane by ene, if a double bond is present. The suffix ane is replaced by yne if a triple bond is present.

If the root is a chain, numbering begins from that end of the chain which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond at the earliest. If there is a tie, the chain is numbered such that the substituents get the lowest locator numbers.

The carbon atoms having a double or triple bond between them are always assigned C1 and C2, if the root is a ring. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond is written before the ene or yne suffix. In case of cycloalkene or cycloalkyne, the locator number is not included explicitly. Prefixes and locator numbers are used for the substituents attached.

Answer to Problem B.23P

The IUPAC name for the given compound is $\text{3, 4-dimethoxycyclohexene}$

Explanation of Solution

The given molecule is:

In this molecule, the largest carbon ring containing the double bond has six carbon atoms. Hence, the root is cyclohexene. The ring is numbered such that the double bonded carbon atoms get C1 and C2 as the locator numbers.

The numbering system is shown below:

At C3 and C4 carbon atoms of the ring, two methoxy substituents are attached.

Thus, a prefix ‘di’ must be used for methoxy substituents to indicate their number.

Thus, the IUPAC name of the compound is $\text{3, 4-dimethoxycyclohexene}$.

Conclusion

The IUPAC name of the compound is written according to the rules for nomenclature.

Interpretation Introduction

(e)

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ane by ene, if a double bond is present. The suffix ane is replaced by yne if a triple bond is present.

If the root is a chain, numbering begins from that end of the chain which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond at the earliest. If there is a tie, then the chain is numbered such that the substituents get the lowest locator numbers.

The carbon atoms having a double or triple bond between them are always assigned C1 and C2, if the root is a ring. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond is written before the ene or yne suffix. In case of cycloalkene or cycloalkyne, the locator number is not included explicitly. Prefixes and locator numbers are used for the substituents attached.

Answer to Problem B.23P

The IUPAC name for the given compound is $\text{3, 3-dimethyl-1-propylcyclohexene}$

Explanation of Solution

The given molecule is:

In this molecule, the largest carbon ring containing the double bond has six carbon atoms. Hence, the root is cyclohexene. The ring is numbered such that the double bonded carbon atoms get C1 and C2 as the locator numbers.

The numbering system is shown below:

At C1 carbon atom of the ring, a substituent propyl is attached. At C3 carbon atom of the ring, two methyl groups are attached. Thus, a prefix ‘di’ must be used for methyl substituents to indicate the number. Out of propyl and methyl substituents, methyl comes first alphabetically, hence it will be written first in the name.

Thus, the IUPAC name of the compound is $\text{3, 3-dimethyl-1-propylcyclohexene}$.

Conclusion

The IUPAC name of the compound is written according to the rules for nomenclature.

Interpretation Introduction

(f)

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ane by ene, if a double bond is present. The suffix ane is replaced by yne if a triple bond is present.

If the root is a chain, numbering begins from that end of the chain which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond at the earliest. If there is a tie, the chain is numbered such that the substituents get the lowest locator numbers.

The carbon atoms having a double or triple bond between them are always assigned C1 and C2, if the root is a ring. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond is written before the ene or yne suffix. In case of cycloalkene or cycloalkyne, the locator number is not included explicitly. Prefixes and locator numbers are used for the substituents attached.

Answer to Problem B.23P

The IUPAC name for the given compound is $\text{3-nitrocyclooctyne}$

Explanation of Solution

The given molecule is:

In this molecule, the largest carbon ring containing the triple bond has eight carbon atoms. Hence, the root is cyclooctayne. The ring is numbered such that the double bonded carbon atoms get C1 and C2 as the locator numbers.

The numbering system is shown below:

At C3 carbon atom of the ring, a substituent nitro is attached.

Thus, the IUPAC name of the compound is $\text{3-nitrocyclooctyne}$.

Conclusion

The IUPAC name of the compound is written according to the rules for nomenclature.