3-Methyl-2-buten-1-ol

3-Methyl-2-buten-1-ol is a natural alcohol. It is one of the most simple terpenes. It is a clear colorless oil that is insoluble in water, but miscible with most common organic solvents. It has a fruity odor and is used occasionally in perfumery.

It is also a building block of isoprenoid alcohols (or 'prenol'), which have a general formula of:

The repeating  moiety in the brackets is called “isoprene”.

Prenol is polymerized by dehydration reactions; when there are at least four isoprene units (n in the above formula is greater than or equal to four), the polymer is called a polyprenol. Polyprenols can contain up to 100 isoprene units (n=100) linked end to end with the hydroxyl group (-OH) remaining at the end. These isoprenoid alcohols are also called ‘terpenols’ These isoprenoid alcohols are important in the acylation of proteins, carotenoids, and fat-soluble vitamins A, E and K.  They are also building blocks for plant oils such as farnesol, and geraniol. Prenol is also a building block of cholesterol (built from six isoprene units), and thus of all steroids.

When the isoprene unit attached to the alcohol is saturated, the compound is referred to as a ‘dolichol’. Dolichols are important as glycosyl carriers in the synthesis of polysaccharides.