Piperonal, also known as heliotropin, is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

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 organic chemistry, aromaticity is a chemical property describing the way in which a conjugated system, conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugati ...

aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

s such as

benzaldehyde Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is among the simplest aromatic aldehydes and one of the most industrially useful. It is a colorless liquid with a characteristic almond-li ...

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 ethanolic extract of the vanilla bean. Synthetic vanillin ...

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 native to North Africa, Iran, and the Arabian Peninsula; it is grown widely in Eurasia, where its leaves and seeds are used as a herb or spice for flavouring ...

vanilla Vanilla is a spice derived from orchids of the genus ''Vanilla (genus), Vanilla'', primarily obtained from pods of the flat-leaved vanilla (''Vanilla planifolia, V. planifolia''). ''Vanilla'' is not Autogamy, autogamous, so pollination ...

, violet flowers, and

black pepper Black pepper (''Piper nigrum'') is a flowering vine in the family Piperaceae, cultivated for its fruit (the peppercorn), which is usually dried and used as a spice and seasoning. The fruit is a drupe (stonefruit) which is about in diameter ...

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 allylbenzene, a type of aromatic organic chemical. Its fragrance is reminiscent of anise or licorice. It is found in small amount ...

or by using a multistep sequence from

catechol Catechol ( or ), also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula . It is the ''ortho'' isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amounts. It ...

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 " accepts"/"receives" an electron from a (called the , , or ''electron donor''). 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 ...

using

dichloromethane Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with ...

Reactions

Piperonal, like all

s, can be

reduced Reduction, reduced, or reduce may refer to: Science and technology Chemistry * Reduction (chemistry), part of a reduction-oxidation (redox) reaction in which atoms have their oxidation state changed. ** Organic redox reaction, a redox reacti ...

to its

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 ...

( piperonyl alcohol) or oxidized to give its

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

( 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, benign prostatic hyperplasia, and pulmonary arterial hypertension. It is taken by mouth. Onset is typically within half an hour and ...

L-DOPA -DOPA, also known as -3,4-dihydroxyphenylalanine and used medically as levodopa, 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 -DO ...

, and

atrasentan Atrasentan, sold under the brand name Vanrafia, is a medication used to reduce proteinuria. It is an endothelin receptor antagonist. It is taken by mouth. Atrasentan was approved for medical use in the United States in April 2025. Medical us ...

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 na ...

. 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 that is used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of t ...

. 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 known as ecstasy (tablet form), and molly (crystal form), is an empathogen–entactogenic drug with stimulant and minor Psychedelic drug, psychedelic properties. In studies, it has been used ...

safrole Safrole is an organic compound with the formula CH2O2C6H3CH2CH=CH2. It is a colorless oily liquid, although impure samples can appear yellow. A member of the phenylpropanoid family of natural products, it is found in sassafras plants, among ot ...

, and piperonal are Category I precursors under regulation no. 273/2004 of the

European Community The European Economic Community (EEC) was a regional organisation 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

Tadalafil vs Sildenafil
{{EB1911 poster, Piperonal Benzaldehydes Benzodioxoles