Question

 

Give the IUPAC name for each of the following carboxylic acids.

Answer 1

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 "-e" with "-oic add".

Numbering is done so 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. 

If any, the identity and location of substituents have 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 call is named, and "-carboxylic add" is added as a suffix.

If the compound contains two carboxyl groups, the suffix "- dioic acid" is added after the parent alkane name.

(a)

The given carboxylic acid can be numbered as follows,

Parent carbon chain              -          Isobutane

Substituent position              -         No substituent

IUPAC name                          -         Isobutyric acid

Hence, the IUPAC name of the given carboxylic acid is Isobutyric acid.

(b)

The given carboxylic acid can be numbered as follows,

Parent carbon chain              -    butane      

Substituent position              -    2-methyl

IUPAC name                          -    2-methylbutanoic acid

Hence, the IUPAC name of the given carboxylic acid is 2-methylbutanoic acid.

(c)

The given carboxylic acid can be numbered as follows,

Parent carbon chain              -         propane 

Substituent position              -        2-chloro, 2-methyl (arranged in alphabetical order)

IUPAC name                          -      2-chloro-2-methylpropanoic acid

Hence, the IUPAC name of the given carboxylic acid is 2-chloro-2-methylpropanoic acid.

(d)

The given carboxylic acid can be numbered as follows,

Parent carbon chain              -          pentane

Substituent position              -         2-chloro, 4-hydroxy (arranged in alphabetical order)

IUPAC name                          -          2-chloro-4-hydroxypentanoic acid

Hence, the IUPAC name of the given carboxylic acid is 2-chloro-4-hydroxypentanoic acid.