Question

The correct IUPAC name of the compound given below is :

• A. $\text{1-carboxy-4-ethyl-3-methylpentanoylchloride}$
• B. $\text{3-methyl-4-(chlorocarbonyl)hexanoic acid}$
• C. $\text{1-carboxy-4-ethyl-3-methylpentanoylchloride}$
• D. $\text{5-carboxy-2-ethyl-3-methylpentanoylchloride}$

Answer 1

The correct option is B $\text{3-methyl-4-(chlorocarbonyl)hexanoic acid}$

Acid Halides ( −COX ) :
Suffix: −oyl halide/ carbonyl halide
Prefix: halocarbonyl

Here, acid halide is not a part of parent chain. It is present as a substituent at the 4th position of the parent chain. So, prefix halocarbonyl is used during the nomenclature of the compound.
So, the correct IUPAC name of the following compound is
$\text{3-methyl-4-(chlorocarbonyl)hexanoic acid}$

Theory :

Aldehydes $(-CHO)$
Suffix: −al/carbaldehyde
Prefix: formyl/oxo .
Oxo is used as prefix when ‘C’ of ‘CHO’ is included in parent chain else ‘formyl’ is used



When ketone group is there in presence of carboxylic acid, then the naming is done as follows :
Ketones ( >C=O )
Suffix: −one
Prefix: oxo/keto