Advanced Topic 852 of 1102 Organic Chemistry
Terpenes
Natural products built from isoprene units, giving scents and flavors.
In-depth explanation of Terpenes
Terpenes are natural products built from isoprene units, each containing five carbon atoms, joined in head-to-tail fashion. They are classified by the number of isoprene units: monoterpenes have C10, sesquiterpenes C15, diterpenes C20, triterpenes C30 and tetraterpenes C40. Terpenes are the main components of many essential oils and give plants their characteristic scents, flavours and pigments. They are also the biosynthetic precursors of steroids and many other natural compounds.
Going deeper: Terpenes
Key ideas: Built from isoprene units (C5H8) joined head to tail (isoprene rule): monoterpenes C10 (limonene, menthol, geraniol), sesquiterpenes C15, diterpenes C20 (retinol), triterpenes C30 (squalene) and tetraterpenes C40 (carotenes). Biosynthesised from isopentenyl pyrophosphate. Provide scents, pigments and the steroid precursor squalene. Contain double bonds, so react with Br2 and ozone.
Common mistakes and connections: Students assume terpenes are straight chains of isoprene, when rings form frequently. Another error is miscounting carbons: monoterpene is C10, two isoprene units. Links to steroids, carbocation cyclisations, and vitamins A, E and K.
Visualization of Terpenes
Terpene classes grow by whole isoprene (C5) units, so carbon counts are multiples of five. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Limonene, a monoterpene, gives oranges and lemons their characteristic citrus smell.
Frequently asked questions about Terpenes
What is Terpenes?
Natural products built from isoprene units, giving scents and flavors.
Is Terpenes a beginner, intermediate or advanced topic?
Terpenes is a advanced topic in Organic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Terpenes?
Study these earlier topics in Organic Chemistry first: Heterocyclic Compounds, Pyridine, Alkaloids.
What comes after Terpenes?
The next topics in Organic Chemistry are Steroids and Pharmaceuticals.
Can I practise Terpenes with quizzes?
Yes. The interactive lesson includes a self-check question on Terpenes, and the Organic Chemistry quiz draws on every topic in this area.
Where Terpenes fits in Organic Chemistry
Terpenes is topic 124 of 148 in Organic Chemistry.