Chemistry - Nomenclature Question with Solution | TestHub
IUPAC nomenclature assigns the principal characteristic group as suffix using seniority: acids > esters > amides > nitriles > aldehydes > ketones > alcohols > amines. The parent chain must contain this group's carbon, with lowest locants given to it first. Consider:
How many carbon atoms are present in the parent chain selected while assigning the IUPAC name to this compound?
Answer:
Solution:
Step 1: Principal characteristic group = –CHO (aldehyde), since aldehyde outranks ketone and alcohol in seniority.
Step 2: Parent chain must be the longest continuous chain that includes the carbon of the –CHO group.
Counting the continuous chain from the aldehyde carbon to the terminal methyl carbon:
CHO(1) – CH₂(2) – CO(3) – CH₂(4) – CH(OH)(5) – CH₃(6)
This gives a chain of 6 carbon atoms, so the parent chain is hexanal.
IUPAC Name: 5-hydroxy-3-oxohexanal