Chapter 3, Problem 3.103EP

(a)

Interpretation Introduction

Interpretation:

The IUPAC name of given compound has to be assigned.

Concept Introduction:

Any organic molecule can be named by using certain rules given by IUPAC (International Union for Pure and applied chemistry).  IUPAC name consists of three parts in major namely Prefix suffix and root word.

Prefix represents the substituent present in the molecule and its position in the root name.

Suffix denotes the presence of functional group if any in the molecule.  It can be an alkene, alkyne, alcohol, carboxylic acid, alcohol etc.

Root word represents the longest continuous carbon skeleton of the organic molecule.

IUPAC rules for naming ether:

• ✓ The base name is found from the longest carbon chain present in ether.
• ✓ The suffix –yl has to be changed to –oxy in order to obtain the alkoxy group name.  For example, ethyl becomes as ethoxy, methyl becomes as methoxy etc.
• ✓ Alkoxy name has to be placed first with the number (carbon atom to which the alkoxy group is attached) followed by the base name.

Answer to Problem 3.103EP

IUPAC name of the given compound is ethoxyethane.

Explanation of Solution

The structure of given compound is shown below,

First step is to identify the longest carbon chain.  In this case it is a two carbon chain.  Hence, the base name is ethane.

Next step is to identify the alkoxy group.  In the given compound, the alkoxy group is found to be ethoxy as it contains two carbon atoms.

Alkoxy name is placed before the base name with the appropriate number that gives information about to which carbon atom the alkoxy group is attached.  In this case as only two carbon atoms is present and hence numbering is not required.  This gives the IUPAC name as ethoxyethane.

Conclusion

IUPAC name for the given compound is assigned.

(b)

Interpretation Introduction

Interpretation:

The IUPAC name of given compound has to be assigned.

Concept Introduction:

Any organic molecule can be named by using certain rules given by IUPAC (International Union for Pure and applied chemistry).  IUPAC name consists of three parts in major namely Prefix suffix and root word.

Prefix represents the substituent present in the molecule and its position in the root name.

Suffix denotes the presence of functional group if any in the molecule.  It can be an alkene, alkyne, alcohol, carboxylic acid, alcohol etc.

Root word represents the longest continuous carbon skeleton of the organic molecule.

IUPAC rules for naming ether:

• ✓ The base name is found from the longest carbon chain present in ether.
• ✓ The suffix –yl has to be changed to –oxy in order to obtain the alkoxy group name.  For example, ethyl becomes as ethoxy, methyl becomes as methoxy etc.
• ✓ Alkoxy name has to be placed first with the number (carbon atom to which the alkoxy group is attached) followed by the base name.

Answer to Problem 3.103EP

IUPAC name of the given compound is 2-methoxy-2-methylpropane.

Explanation of Solution

Given structure of ether is,

First step is to identify the longest carbon chain.  In this case it is a three carbon chain.  Hence, the parent alkane is propane.

The substituent present in the longest carbon chain is a methyl group at the second carbon atom.  Therefore, the base name is 2-methylpropane.

Next step is to identify the alkoxy group.  In the given compound, the alkoxy group is found to be methoxy as it contains only one carbon atom.

Alkoxy name is placed before the base name with the appropriate number that gives information about to which carbon atom the alkoxy group is attached.  This gives the IUPAC name as 2-methoxy-2-methylpropane.

Conclusion

IUPAC name for the given compound is assigned.

(c)

Interpretation Introduction

Interpretation:

The IUPAC name of given compound has to be assigned.

Concept Introduction:

IUPAC rules for naming alcohols that contain single hydroxyl group:

• • Longest carbon chain has to be identified that contains hydroxyl group also.  The chain name is obtained by replacing the letter “-e” in alkane with “-ol”.  If the compound contains a unsaturated bond, then the respective name has to be changed with regard to alkane.
• • The numbering has to be given so that the hydroxyl group gets the least numbering.
• • Name and location of any other substituent present in the chain has to be identified.
• • If in a ring the hydroxyl group is present, then that carbon is numbered 1 and the numbering then proceeds counterclockwise or clockwise in a way that substituents present if any gets the least numbering.
• • Hydroxyl group as a substituent in a molecule is named as hydroxy group rather than hydroxyl group.
• • If the compound contains bulky groups on same side of the double bond, then it is a cis isomer and if the bulkyl groups are present on opposite side of the double bond, then it is a trans isomer.
• • In case of cycloalkane compounds, if the substitutions are present on same side of the ring of carbon atoms, it is a cis isomer.  If the substitutions are present above and below the ring, then it is a trans isomer.

IUPAC rules for naming alcohols that contain more than one hydroxyl group:

• • The same rules said above is followed but the prefix di-, tri-, tetra etc is added corresponding to the number of hydroxyl groups that is present.

Answer to Problem 3.103EP

IUPAC name of the given compound is methoxymethanol.

Explanation of Solution

The structure of given compound is shown below,

The given compound has two functional group namely, hydroxyl group and a alkoxy group.  Alcohol has got more preference over ether.  Therefore, the IUPAC name is given by using the parent as alcohol.  In this case the parent alcohol is found to be methanol.  The substituent that is present in the methanol is a methoxy group.  Therefore, the IUPAC name of the given compound can be written as methoxymethanol.

Conclusion

IUPAC name for the given compound is assigned.

(d)

Interpretation Introduction

Interpretation:

The IUPAC name of given compound has to be assigned.

Concept Introduction:

Any organic molecule can be named by using certain rules given by IUPAC (International Union for Pure and applied chemistry).  IUPAC name consists of three parts in major namely Prefix suffix and root word.

Prefix represents the substituent present in the molecule and its position in the root name.

Suffix denotes the presence of functional group if any in the molecule.  It can be an alkene, alkyne, alcohol, carboxylic acid, alcohol etc.

Root word represents the longest continuous carbon skeleton of the organic molecule.

IUPAC rules for naming ether:

• ✓ The base name is found from the longest carbon chain present in ether.
• ✓ The suffix –yl has to be changed to –oxy in order to obtain the alkoxy group name.  For example, ethyl becomes as ethoxy, methyl becomes as methoxy etc.
• ✓ Alkoxy name has to be placed first with the number (carbon atom to which the alkoxy group is attached) followed by the base name.

Answer to Problem 3.103EP

IUPAC name of the given compound is 2-methylanisole.

Explanation of Solution

The structure of given compound is shown below,

First step is to identify the longest carbon chain.  In this case it is a six carbon aromatic ring with a methoxy group substituent.  Hence, the base name is anisole.

Next step is to identify the substituent present in the given structure.  It is found that a methyl group is present in the second carbon atom of the aromatic benzene ring.

The substituent methyl group is present on the second carbon atom.  The parent compound name is anisole (methoxybenzene).  This gives the IUPAC name as 2-methylanisole.

Conclusion

IUPAC name for the given compound is assigned.