Question

Give the IUPAC name for each compound.

a.

b.

c.

d.

Short answer

Answer

1. 4,4-dipropyl-1-heptyne
2. 5-chloro-5,6-dimethyl-3-octyne
3. 4-ethyl-7,7-dimethyl-1-decen-5-yne
4. 3-isopropyl-1,5-octadlyne

Step-by-step solution

IUPAC nomenclature 

The standard naming method for assigning a name for an organic molecule is known as IUPAC nomenclature.

Rules for assigning IUPAC nomenclature

Select the longest chain containing the triple bond.If more than one groups are present, the longest chain selected must contain all the groups.

Number the longest chain such that the triple bond occupies the lowest numbering.

For naming, the suffix “ane” is replaced by the suffix “yne,” and the substituents are arranged in alphabetical order, excluding the prefix (in case of more than one similar group).

Number the longest chain such that the triple bond occupies the lowest number

(a)

The longest chain contains seven carbon atoms. Therefore, parent alkane: heptane;

Substituents: two propyl groups on the fourth carbon.

The IUPAC name is mentioned below:

4,4-dipropyl-1-heptyne

(b)

The longest chain contains eight carbon atoms. Therefore, parent alkane: octane;

Substituents: one methyl and one chloro group on fifth carbon and one methyl group at the sixth carbon.

The IUPAC name is mentioned below:

5-chloro-5,6-dimethyl-3-octyne

(c)

In the given compound, the triple-bond occupies the same number irrespective of side. The numbering is then based on the lowest number to be occupied by the unsaturated side (double bond).

The longest chain contains ten carbon atoms. Therefore, parent alkane: decane;

Substituents: one ethyl group at fourth carbon and two ethyl groups at seventh carbon.

The IUPAC name is mentioned below:

4-ethyl-7,7-dimethyl-1-decen-5-yne

(d)

The longest chain contains eight carbon atoms. Therefore, parent alkane: octane;

Substituents: one iso-propyl group at the third carbon.

The IUPAC name is mentioned below:

3-isopropyl-1,5-octadiyne