Chapter 5, Problem 5.33EP

(a)

Interpretation Introduction

Interpretation:

IUPAC name for the acrylic acid has to be given.

Concept Introduction:

For naming a carboxylic acid in IUPAC nomenclature, the suffix “-oic” is added to the parent alkane name.

IUPAC rules for naming a carboxylic acid:

• The longest parent carbon chain is identified that includes the carboxyl group.
• The parent chain name is changed by replacing the suffix “-e” with “-oic acid”.
• Numbering is done in a way that the carboxyl group is designated as number 1.  This is not indicated in the part of the name because for aldehyde, the carboxyl carbon is always numbered 1.
• The identity and location of substituents if any has to be determined and this information has to be added in front of the IUPAC name.
• If the carboxyl functional group is attached to a ring of carbon atoms, the ring is named and “-carboxylic acid” is added as suffix.
• If the compound contains two carboxyl groups, then suffix “-dioic acid” is added after the parent alkane name.

Answer to Problem 5.33EP

IUPAC name of acrylic acid is propenoic acid.

Explanation of Solution

Structure of acrylic acid is,

The longest continuous carbon chain has to be found out with the carboxyl group in it.  In this it is a three carbon chain.  The structure contains a double bond between carbon atoms. Hence, the parent is propene.  The given structure contains a carboxyl group.  The carboxylic acid is named by replacing the suffix “-e” with suffix “-oic acid”.  This gives the name of carboxylic acid as propenoic acid.

Looking for substituents it is found that there are no substituents present on the carbon chain.  Hence, the IUPAC name of the acrylic acid is propenoic acid.

Conclusion

IUPAC name of acrylic acid is given.

(b)

Interpretation Introduction

Interpretation:

IUPAC name for the lactic acid has to be given.

Concept Introduction:

For naming a carboxylic acid in IUPAC nomenclature, the suffix “-oic” is added to the parent alkane name.

IUPAC rules for naming a carboxylic acid:

• The longest parent carbon chain is identified that includes the carboxyl group.
• The parent chain name is changed by replacing the suffix “-e” with “-oic acid”.
• Numbering is done in a way that the carboxyl group is designated as number 1.  This is not indicated in the part of the name because for aldehyde, the carboxyl carbon is always numbered 1.
• The identity and location of substituents if any has to be determined and this information has to be added in front of the IUPAC name.
• If the carboxyl functional group is attached to a ring of carbon atoms, the ring is named and “-carboxylic acid” is added as suffix.
• If the compound contains two carboxyl groups, then suffix “-dioic acid” is added after the parent alkane name.

Answer to Problem 5.33EP

IUPAC name of lactic acid is 2-hydroxypropanoic acid.

Explanation of Solution

Structure of lactic acid is,

The longest continuous carbon chain has to be found out with the carboxyl group in it.  In this it is a three carbon chain.  The parent alkane is propane.  The given structure contains a carboxyl group.  The carboxylic acid is named by replacing the suffix “-e” with suffix “-oic acid”.  This gives the name of carboxylic acid as propanoic acid.

Looking for substituents it is found that there is a hydroxyl group at the second carbon atom.  Hence, the IUPAC name of the lactic acid is 2-hydroxypropanoic acid.

Conclusion

IUPAC name of lactic acid is given.

(c)

Interpretation Introduction

Interpretation:

IUPAC name for the maleic acid has to be given.

Concept Introduction:

For naming a carboxylic acid in IUPAC nomenclature, the suffix “-oic” is added to the parent alkane name.

IUPAC rules for naming a carboxylic acid:

• The longest parent carbon chain is identified that includes the carboxyl group.
• The parent chain name is changed by replacing the suffix “-e” with “-oic acid”.
• Numbering is done in a way that the carboxyl group is designated as number 1.  This is not indicated in the part of the name because for aldehyde, the carboxyl carbon is always numbered 1.
• The identity and location of substituents if any has to be determined and this information has to be added in front of the IUPAC name.
• If the carboxyl functional group is attached to a ring of carbon atoms, the ring is named and “-carboxylic acid” is added as suffix.
• If the compound contains two carboxyl groups, then suffix “-dioic acid” is added after the parent alkane name.

Answer to Problem 5.33EP

IUPAC name of maleic acid is cis-butenedioic acid.

Explanation of Solution

Structure of maleic acid is,

The longest continuous carbon chain has to be found out with the carboxyl group in it.  In this it is a four carbon chain.  The structure contains a double bond in it.  The parent carbon chain is butene.  The given structure contains two carboxyl groups.  The carboxylic acid is named by adding suffix “-dioic acid”.  This gives the name of carboxylic acid as butenedioic acid.

Looking for substituents it is found that there are no substituents present in the carbon chain.  Stereochemistry is possible across the double bond.  As the two hydrogen atoms are on the same side of double bond, the configuration at the double bond is “cis”.  This has to be included in the name to get the IUPAC name.  IUPAC name of the maleic acid is found as cis-butenedioic acid.

Conclusion

IUPAC name of maleic acid is given.

(d)

Interpretation Introduction

Interpretation:

IUPAC name for the glycolic acid has to be given.

Concept Introduction:

For naming a carboxylic acid in IUPAC nomenclature, the suffix “-oic” is added to the parent alkane name.

IUPAC rules for naming a carboxylic acid:

• The longest parent carbon chain is identified that includes the carboxyl group.
• The parent chain name is changed by replacing the suffix “-e” with “-oic acid”.
• Numbering is done in a way that the carboxyl group is designated as number 1.  This is not indicated in the part of the name because for aldehyde, the carboxyl carbon is always numbered 1.
• The identity and location of substituents if any has to be determined and this information has to be added in front of the IUPAC name.
• If the carboxyl functional group is attached to a ring of carbon atoms, the ring is named and “-carboxylic acid” is added as suffix.
• If the compound contains two carboxyl groups, then suffix “-dioic acid” is added after the parent alkane name.

Answer to Problem 5.33EP

IUPAC name of glycolic acid is 2-hydroxyethanoic acid.

Explanation of Solution

Structure of glycolic acid is,

The longest continuous carbon chain has to be found out with the carboxyl group in it.  In this it is a two carbon chain.  The parent alkane is ethane.  The given structure contains a carboxyl group.  The carboxylic acid is named by replacing the suffix “-e” with suffix “-oic acid”.  This gives the name of carboxylic acid as ethanoic acid.

Looking for substituents it is found that there is a hydroxyl group at the second carbon atom.  Hence, the IUPAC name of the glycolic acid is 2-hydroxyethanoic acid.

Conclusion

IUPAC name of glycolic acid is given.