Question

The IUPAC name of the following compound is:

(a)- 3,5-dimethyl-4-propyl hept-6-en-1-yne
(b)- 3-methyl-1-4-(3-methyl prop-1-enyl)-1-heptyne
(c)- 3-methyl-1-4-(1-methyl prop-1-enyl)-1-heptyne
(d)- 3,5-dimethyl-4-propyl hept-1-en-6-yne

Answer 1

Hint: In the given compound there are three branches, so take the chain of the carbon atom in which both the functional groups, i.e., the double bond and the triple will be present. Give presence to the double bond in the double and the triple bond.

Complete answer:
While naming the chain of the carbon atom first we have to find the longest chain, and this longest chain must have the functional group if the compound has the longest chain.
In the compound given above, there are two functional groups, i.e., the double bond and the triple bond.
In the given compound there are three branches, so take the chain of the carbon atom in which both the functional groups, i.e., the double bond and the triple will be present. Give presence to the double bond in the double and the triple bond.

So, in the given compound the numbering will start from the double bond and the last carbon atom in the chain will have the triple bond. The longest chain will be of seven carbon atoms. In the third and the fifth position, one methyl group is present and at the fourth position, the propyl group is present. Hence, the methyl group will be named first and the propyl will be named because alphabetically m comes first, and then the p comes.
So the name of the compound will be 3,5-dimethyl-4-propyl hept-1-en-6-yne.

Therefore, the correct answer is an option (d).

Note:
It must be noted that when two functional groups are present on the single carbon chain then the number must be done in such a way that the smaller number must be given to the functional group having a higher preference.