Question

IUPAC name of the following molecule is

• A. 6-Bromo-4-chloro-3,7-diethyl-5-oxo-8-yne-2-nonene
• B. 6-Chloro-4-bromo-3,7-diethyl-5-keto-7-ene-1-nonyne
• C. 4-Chloro-6-bromo-3,7-diethyl-5-keto-8-yn-2-nonene
• D. 4-Bromo-6-chloro-3,7-diethylnon-7-en-1-yn-5-one

Hint:

When naming organic molecules with multiple functional groups, identify the principal functional group based on priority rules. The longest carbon chain containing the principal functional group is the parent chain. Number the chain to give the principal functional group the lowest possible number. Other functional groups are treated as substituents. Arrange the substituents alphabetically in the name.

Answer 1

The Correct Option is D

To determine the IUPAC name of the given molecule, we need to follow the IUPAC naming conventions: 1.
**Identify the longest carbon chain containing the functional groups with the highest priority.
** The functional groups present are a ketone (\( -C=O \)), an alkene (\( -C=C- \)), and an alkyne (\( -C \equiv C- \)).
The priority order is ketone>alkene = alkyne>halide.
Thus, the longest chain containing the ketone should be numbered to give the ketone the lowest possible number.
The longest chain has 9 carbon atoms, so the parent hydrocarbon is nonane.
2.
**Number the carbon chain.
** We need to number the chain such that the ketone gets the lowest number.
Numbering from left to right gives the ketone at position 5, the alkyne starting at position 1, and the alkene starting at position 7.
Numbering from right to left would give the ketone at position 5, the alkyne starting at position 9, and the alkene starting at position 3.
Since the ketone has the highest priority, we number from left to right.
The parent chain is nonane, and with the functional groups, it becomes nonenynone.
The ketone is at position 5, the alkyne starts at position 1, and the alkene starts at position 7.
So, the parent name is non-7-en-1-yn-5-one.
3.
**Identify and name the substituents.
** The substituents are: - A bromine atom (Br) at position 4 (numbered from the ketone priority).
- A chlorine atom (Cl) at position 6.
- An ethyl group (\( -C_2H_5 \)) at position 3.
- An ethyl group (\( -C_2H_5 \)) at position 7.
4.
**Arrange the substituents in alphabetical order.
** The alphabetical order is: bromo, chloro, diethyl.
5.
**Combine the substituent names and positions with the parent name.
** The IUPAC name is: 4-bromo-6-chloro-3,7-diethylnon-7-en-1-yn-5-one.
This matches option (D).