Question

Write the structure of 4-chloropentan-2-one.

Answer 1

Hint: First part represents the substituent with its position and number of carbon atoms in the parent chain. The ‘one’ represents the ketone functional group.

Complete step by step answer:
The IUPAC rules used for the naming the ketone are used to draw the structure of ketone.
The IUPAC rules for the naming of ketone are as follows:
Determine the longest carbon chain and determine the substituents attached to the chain.
If two same long chains are present then select the more substituted chain.
Give the numbering to the carbon atoms of the chains so all the substituents get the lowest numbering.
Arrange the substituents in alphabetical order with their position in the chain.
If the same substituent is present more than one, then add ‘di’ for two, ‘tri’ for three, and so on.
‘pentan’ indicates that the longest carbon chain is of five carbon atoms.
Draw the parent chain as follows:

‘one’ suffix is used to show the presence of ketone. 2-one means the ketone group is present in the second carbon.
Draw the ketone group $\left( {{\text{C = O}}} \right)$ at second carbon as follows:

4-chloro means that the substituent chlorine is present in the fourth carbon.
Draw the chlorine substituent at fourth carbon s follows;

Therefore the structure of 4-chloropentan-2-one.

Note: The simple five-carbon ketone (keto group at carbon-2) is known as pentan-2-one where ‘pent’ indicated five carbons and ‘one’ indicates a keto group. To specify the position of the keto group the name is broken into two parts ‘pentan’ and ‘one’.