Question: Locate the isoprene units in biformene, a component of amber, and classify biformene as a monoterpene, sesquiterpene etc.

Isoprene units come under the category of unsaturated hydrocarbons. It comprises five carbon atoms possessing double bonds. Carotene is an example of an isoprenoid.

Biformene is a kind of terpene comprising the molecular formula C₂₀H₃₂ . It is a natural product found in the flower Helianthus decapetalus.

The skeletal structure of biformene can be given as:

Skeletal structure of biformene

Terpenes comprise repeating five-carbon units termed isoprene units. Each isoprene unit shall consist of five carbon atoms, four carbons in a row, and one-carbon branch on a middle carbon.

The isoprene units in the given terpene, biformene are indicated in blue color as:

Isoprene units of biformene

The given terpene comprises four isoprene units. Hence, biformene is a sesquiterpene.