Piperonal, also known as heliotropin, is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
which is commonly found in fragrances and flavors.
[Karl-Georg Fahlbusch, Franz-Josef Hammerschmidt, Johannes Panten, Wilhelm Pickenhagen, Dietmar Schatkowski, Kurt Bauer, Dorothea Garbe and Horst Surburg "Flavors and Fragrances" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2003. ] The molecule is structurally related to other
aromatic
In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...
aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
s such as
benzaldehyde
Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful.
It is a colorless liquid with a characteristic almond-like odor. ...
and
vanillin
Vanillin is an organic compound with the molecular formula . It is a phenolic aldehyde. Its functional groups include aldehyde, hydroxyl, and ether. It is the primary component of the extract of the vanilla bean. Synthetic vanillin is now used ...
.
Natural occurrence
Piperonal naturally occurs in various plants. Examples include
dill
Dill (''Anethum graveolens'') is an annual herb in the celery family Apiaceae. It is the only species in the genus ''Anethum''. Dill is grown widely in Eurasia, where its leaves and seeds are used as a herb or spice for flavouring food.
Growth ...
,
vanilla
Vanilla is a spice derived from orchids of the genus ''Vanilla (genus), Vanilla'', primarily obtained from pods of the Mexican species, flat-leaved vanilla (''Vanilla planifolia, V. planifolia'').
Pollination is required to make the p ...
,
violet flowers, and
black pepper
Black pepper (''Piper nigrum'') is a flowering vine in the family Piperaceae, cultivated for its fruit, known as a peppercorn, which is usually dried and used as a spice and seasoning. The fruit is a drupe (stonefruit) which is about in diame ...
.
Preparation
Piperonal can be prepared by the oxidative cleavage of
isosafrole
Isosafrole is an organic compound that is used in the fragrance industry. Structurally, the molecule is related to phenylpropene, a type of aromatic organic chemical. Its fragrance is reminiscent of anise or licorice. It is found in small amoun ...
or by using a multistep sequence from
catechol
Catechol ( or ), also known as pyrocatechol or 1,2-dihydroxybenzene, is a toxic organic compound with the molecular formula . It is the ''ortho'' isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amoun ...
or
1,2-methylenedioxybenzene. Synthesis from the latter chemical is accomplished through a
condensation reaction
In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a ...
with
glyoxylic acid
Glyoxylic acid or oxoacetic acid is an organic compound. Together with acetic acid, glycolic acid, and oxalic acid, glyoxylic acid is one of the C2 carboxylic acids. It is a colourless solid that occurs naturally and is useful industrially.
Str ...
followed by
cleaving the resulting
α-hydroxy acid with an
oxidizing agent
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "Electron acceptor, accepts"/"receives" an electron from a (called the , , or ). In ot ...
.
Synthesis from catechol requires an additional step,
Williamson ether synthesis
The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol ( alkoxide). This reaction was developed by Alexander Williamson in 1850. Typically it involves the reaction of an alkoxide i ...
using
dichloromethane
Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour is widely used as a solvent. Although it is not miscible with ...
.
Reactions
Piperonal, like all
aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
s, can be
reduced to its
alcohol
Alcohol most commonly refers to:
* Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom
* Alcohol (drug), an intoxicant found in alcoholic drinks
Alcohol may also refer to:
Chemicals
* Ethanol, one of sev ...
(piperonyl alcohol) or oxidized to give its
acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
(piperonylic acid).
Piperonal can be used in the synthesis of some pharmaceutical drugs including
tadalafil
Tadalafil, sold under the brand name Cialis among others, is a medication used to treat erectile dysfunction (ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension. It is taken by mouth. Onset is typically within half a ...
,
L-DOPA
-DOPA, also known as levodopa and -3,4-dihydroxyphenylalanine, is an amino acid that is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize -DOPA ...
, and
atrasentan
Atrasentan is an experimental drug that is being studied for the treatment of various types of cancer, including non-small cell lung cancer. It is also being investigated as a therapy for diabetic kidney disease.
Atrasentan failed a phase 3 tria ...
.
Fragrance
Piperonal has a floral odor which is commonly described as being similar to that of vanillin or
cherry
A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit).
Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The nam ...
. For this reason it is commonly used in fragrances and
artificial flavors
A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the gust ...
.
The compound was named Heliotropin after the 'cherry pie' notes found in the
heliotrope flower's fragrance (even though the chemical is not present in the flower's true aroma). Perfumers began to use the fragrance for the first time by the early 1880s.
[The Force of Fashion in Politics and Society]
Global Perspectives from Early Modern to Contemporary Times By Beverly Lemire It is commonly used to add vanilla or almond nuances, generally imparting balsamic, powdery, and floral aspects to a scent's character.
Piperonyl acetate is a synthetic cherry flavoring.
Use in MDMA Manufacture
Due to their role in the manufacture of
MDMA
3,4-Methylenedioxymethamphetamine (MDMA), commonly seen in Tablet (pharmacy), tablet form (ecstasy) and crystal form (molly or mandy), is a potent empathogen–entactogen with stimulant properties primarily used for Recreational dru ...
, safrole,
isosafrole
Isosafrole is an organic compound that is used in the fragrance industry. Structurally, the molecule is related to phenylpropene, a type of aromatic organic chemical. Its fragrance is reminiscent of anise or licorice. It is found in small amoun ...
, and piperonal are Category I precursors under regulation no. 273/2004 of the
European Community
The European Economic Community (EEC) was a regional organization created by the Treaty of Rome of 1957,Today the largely rewritten treaty continues in force as the ''Treaty on the functioning of the European Union'', as renamed by the Lisbo ...
.
References
External links
{{EB1911 poster, Piperonal
Benzaldehydes
Benzodioxoles