Question

What is the IUPAC name of the given compound?
${C_2}{H_5} - C\left( O \right) - C{H_2}OH$
A) \[2 - Ethyl{\text{ }}prop - 2 - en - 1 - ol\]
B) \[2 - Hydroxymethyl{\text{ }}butan - 1 - ol\]
C) \[1 - hydroxy{\text{ }}butan - 2 - one\]
D) \[2 - Methyl - 3 - hydroxyprop - 1 - ene\]

Answer 1

Hint: The molecular formula for the given structure is ${C_4}{H_8}{O_2}$ . It is a four carbon chain molecule consisting of one ketone group and one hydroxyl group. Using the IUPAC nomenclature rules, find the IUPAC name for the given compound.

Complete answer:
 We can use the IUPAC nomenclature rules to name the given compound.
1. According to the IUPAC rules, the chain containing the highest number of Carbons is considered to be the parent chain and the main functional group should be a part of the chain.
Therefore the parent chain consists of four Carbon atoms.
2. We know that in IUPAC rules, the carbon atoms should be numbered such that the sum of the positions of substituents is least. So we can number the Carbon atoms as follows.

3. There are two functional groups in this compound. According to the IUPAC rules, we should be giving priority to the Ketone group so the Ketone becomes the suffix and the alcohol group becomes the prefix.
Since the compound has four Carbon atoms in the parent chain, the central term would be ‘butan’ and the functional group attached to it is Ketone on the second carbon so it becomes ‘Butan-2-one’.
Finally, we add the hydroxy prefix to the name and since the hydroxy group is attached to the first Carbon so the name becomes 1-hydroxy butan-2-one.

Therefore the IUPAC name of the given structure is 1-hydroxy butan-2-one i.e. option ‘C’.

Notes: Given compound contains one ketone and one alcohol group in it and its molecular formula can be written as ${C_4}{H_8}{O_2}$ . Since this compound consists of two functional groups, we use the IUPAC rules to prioritize ketone groups over alcohol.