Prenol, or 3-methyl-2-buten-1-ol, is a natural

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

. It is one of the most simple

terpenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic compound, organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeabl ...

s. It is a clear colorless oil that is reasonably soluble in water and miscible with most common organic solvents. It has a fruity odor and is used occasionally in perfumery. Prenol occurs naturally in citrus fruits, cranberry, bilberry, currants, grapes, raspberry, blackberry, tomato, white bread, hop oil, coffee, arctic bramble, cloudberry and passion fruit. It is also manufactured industrially by

BASF BASF SE (), an initialism of its original name , is a European Multinational corporation, multinational company and the List of largest chemical producers, largest chemical producer in the world. Its headquarters are located in Ludwigshafen, Ge ...

(in

Ludwigshafen Ludwigshafen, officially Ludwigshafen am Rhein (; meaning "Ludwig I of Bavaria, Ludwig's Port upon the Rhine"; Palatine German dialects, Palatine German: ''Ludwichshafe''), is a List of cities and towns in Germany, city in the German state of Rh ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

) and by

Kuraray is a Japanese manufacturer of chemicals, fibers and other materials. Their main manufacturing facilities are located in Kurashiki, Okayama. The company's Tokyo administrative offices are located in Otemachi, Chiyoda in the Ote Center Building ...

(in Asia) as an intermediate to pharmaceuticals and aroma compounds. Global production in 2001 was between 6000 and 13,000 tons.

Industrial production

Prenol is produced industrially by the reaction of

formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

with

isobutene Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. Productio ...

, followed by the isomerization of the resulting

isoprenol Isoprenol, also known as 3-methylbut-3-en-1-ol, is a hemiterpene Alcohol (chemistry), alcohol. It is produced industrially as an intermediate to 3-methylbut-2-en-1-ol (prenol): global production in 2001 can be estimated as 6–13 thousand ton ...

(3-methyl-3-buten-1-ol). : Isoprenol prepn

Uses

Prenol is mainly used as a precursor to

citral Citral is an acyclic monoterpene aldehyde. Being a monoterpene, it is made of two isoprene units. Citral is a collective term which covers two geometric isomers that have their own separate names; the ''E''-isomer is named geranial (''trans''- ...

, an intermediate in the industrial production of

vitamin A Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most not ...

, E, and K. For this purpose, prenol is oxidized to the aldehyde prenal.

Polyprenols

Prenol is a building block of isoprenoid alcohols, which have the general formula: :H– H₂CCH₃=CHCH₂sub>''n''–OH The repeating C₅H₈

moiety Moiety may refer to: __NOTOC__ Anthropology * Moiety (kinship), either of two groups into which a society is divided ** A division of society in the Iroquois societal structure in North America ** An Australian Aboriginal kinship group ** Native Ha ...

in the brackets is called

isoprene Isoprene, or 2-methyl-1,3-butadiene, is a common volatile organic compound with the formula CH2=C(CH3)−CH=CH2. In its pure form it is a colorless volatile liquid. It is produced by many plants and animals (including humans) and its polymers ar ...

, and these compounds are sometimes called 'isoprenols'. They should not be confused with

, which is an isomer of prenol with a terminal double bond. The simplest isoprenoid alcohol is

geraniol Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil and palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility i ...

(''n'' = 2): higher oligomers include

farnesol Farnesol is a natural 15-carbon organic compound which is an acyclic sesquiterpene alcohol. Under standard conditions, it is a colorless liquid. It is hydrophobic, and thus insoluble in water, but miscible with oils. As the pyrophosphate ester, ...

(''n'' = 3) and

geranylgeraniol Geranylgeraniol is a diterpenoid alcohol. It is a colorless waxy solid. It is an important intermediate in the biosynthesis of other diterpenes, of vitamins E, and of K. It is a derivative of geranylgeraniol pyrophosphate, which is a precursor ...

(''n'' = 4). When the isoprene unit attached to the alcohol is

saturated Saturation, saturated, unsaturation or unsaturated may refer to: Chemistry *Saturated and unsaturated compounds, a classification of compounds related to their ability to resist addition reactions **Degree of unsaturation **Saturated fat or satur ...

, the

compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struc ...

is referred to as a

dolichol Dolichol refers to any of a group of long-chain mostly unsaturated organic compounds that are made up of varying numbers of isoprene units terminating in an α-saturated isoprenoid group, containing an alcohol functional group. Functions Dolicho ...

. Dolichols are important as glycosyl carriers in the

synthesis Synthesis or synthesize may refer to: Science Chemistry and biochemistry *Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors **Organic synthesis, the chemical synthesis of organi ...

polysaccharides Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wat ...

. They also play a major role in protecting cellular membranes, stabilising cell proteins and supporting the body's immune system. Prenol is polymerized by

dehydration reaction In chemistry, a dehydration reaction is a chemical reaction that involves the loss of an H2O from the reacting molecule(s) or ion(s). This reaction results in the release of the H2O as water. When the reaction involves the coupling of two molecu ...

s; when there are at least five isoprene units (''n'' in the above formula is greater than or equal to five), the

polymer A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...

is called a

polyprenol Polyprenols are natural long-chain isoprenoid alcohols of the general formula H-(C5H8)n-OH, where n is the number of isoprene units. Any prenol with more than 4 isoprene units is a polyprenol. Polyprenols play an important function, acting as nat ...

. Polyprenols can contain up to 100 isoprene units (''n'' = 100) linked end to end with the

hydroxyl group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

(–OH) remaining at the end. These long-chain isoprenoid alcohols are also called ‘terpenols’. They are important in the acylation of

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, re ...

carotenoid Carotenoids () are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, cana ...

s, and fat-soluble vitamins A, E and K. Polyprenols also play a vital role in

cell metabolism ''Cell Metabolism'' is a monthly peer-reviewed scientific journal covering physiology, with an emphasis on understanding the molecular basis of how the body self-regulates in the face of change, and how disturbances in these balances can lead to di ...

. Research indicates that ingested polyprenols are metabolised by human and animal liver into

s which then take part in the dolichol phosphate cycle and are therefore easily assimilated by humans and animals. The pharmacological activity of polyprenols is based on their substitutive effect in the case of dolichol deficits which are observed with chronic inflammatory, degenerative and oncological diseases. Live conifer needles are one of the richest and most widely available sources for polyprenol extraction in the world. Commercial extraction of polyprenols involves a soft extraction procedure that enables them to be extracted without destroying their biological activity..

Notes

References

External links

*{{SIDS, id=556821 , name=3-Methyl-2-buten-1-ol Flavors Hemiterpenes Alkenols