Question

Mark the isoprene units in menthol, $\mathbf{\beta }$-selinene, and camphor.

Short answer

The isoprene units are marked in orange color.

Menthol

$\beta$-selinene

Camphor

Step-by-step solution

Isoprene

The organic compound that has five carbons in the hydrocarbon skeleton with two double bonds is isoprene. This compound makes very basic structural units for rubbers.

Isoprene units

The main rule to identify an isoprene unit is that it should contain five carbon atoms. The isoprene unit is made up of two parts: one is the head and another one is the tail; the head is at the branched end and the tail is at the un-branched end.

Isoprene units of the given compounds

The isoprene units for the given compounds are marked in orange color and the non-isoprene units are marked in black color only.

Menthol

$\beta$-selinene

Camphor