hemiterpenes

Hemiterpenes are a class of organic compounds that are built from isoprene units, specifically one isoprene unit. This means their chemical structure is based on a five-carbon skeleton derived from isoprene (2-methyl-1,3-butadiene). The general formula for hemiterpenes is C5H8. While they are the simplest form of terpenes, they are often not found in isolation but rather as components within larger, more complex terpenoid structures.

The most well-known hemiterpene is isoprene itself, which is a volatile organic compound released by many plants. Isoprene plays a role in plant physiology and can contribute to atmospheric chemistry. Another notable hemiterpene is prenol, also known as isoprenol or 3-methyl-2-buten-1-ol. Prenol is an alcohol derivative of isoprene and is a building block for other, larger terpenes and terpenoids. Other examples include isovaleric acid and various alcohols and aldehydes derived from isoprene.

Hemiterpenes are biosynthesized in plants and microorganisms through pathways involving the mevalonate pathway or the methylerythritol phosphate pathway. Although simple in structure, these compounds are important as intermediates in the biosynthesis of a vast array of more complex natural products, including monoterpenes, sesquiterpenes, diterpenes, and carotenoids, which have diverse biological functions and applications.