Piperonal

Piperonal, also known as heliotropin, is an organic compound which is commonly found in fragrances and flavors.^[3] The molecule is structurally related to other aromatic aldehydes such as benzaldehyde and vanillin.

Piperonal

Names
Preferred IUPAC name 2H-1,3-Benzodioxole-5-carbaldehyde
Other names Heliotropin; Heliotropine; Piperonyl aldehyde; Protocatechuic aldehyde methylene ether; 3,4-methylenedioxybenzaldehyde;
Identifiers
CAS Number	120-57-0 Y
3D model (JSmol)	Interactive image Interactive image
Beilstein Reference	131691
ChEBI	CHEBI:8240 Y
ChEMBL	ChEMBL271663 Y
ChemSpider	13859497 Y
ECHA InfoCard	100.004.009
EC Number	204-409-7
Gmelin Reference	4186
KEGG	C10812
PubChem CID	8438
UNII	KE109YAK00 Y
CompTox Dashboard (EPA)	DTXSID7025924
InChI InChI=1S/C8H6O3/c9-4-6-1-2-7-8(3-6)11-5-10-7/h1-4H,5H2 N Key: SATCULPHIDQDRE-UHFFFAOYSA-N N
SMILES O=Cc1ccc2OCOc2c1 c1cc2c(cc1C=O)OCO2
Properties
Chemical formula	C8H6O3
Molar mass	150.133 g·mol−1
Appearance	Colorless crystals[1]
Density	1.337 g/cm3
Melting point	37 °C (99 °F; 310 K)[1]
Boiling point	263 °C (505 °F; 536 K)[1]
Solubility in water	Soluble in 500 parts[1]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H317
Precautionary statements	P261, P272, P280, P302+P352, P321, P333+P313, P363, P501
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2700 mg/kg (orally in rats)[1]
Legal status	BR: Class D1 (Drug precursors)[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Natural occurrence

Piperonal naturally occurs in various plants. Examples include dill, vanilla, violet flowers, and black pepper.

Preparation

Piperonal can be prepared by the oxidative cleavage of isosafrole or by using a multistep sequence from catechol or 1,2-methylenedioxybenzene. Synthesis from the latter chemical is accomplished through a condensation reaction with glyoxylic acid followed by cleaving the resulting α-hydroxy acid with an oxidizing agent.^[3][4][5] Synthesis from catechol requires an additional step, Williamson ether synthesis using dichloromethane.^[6]

Reactions

Piperonal, like all aldehydes, can be reduced to its alcohol (piperonyl alcohol) or oxidized to give its acid (piperonylic acid).

Piperonal can be used in the synthesis of some pharmaceutical drugs including tadalafil,^[7] L-DOPA,^[8] and atrasentan.^[9]

Fragrance

Piperonal has a floral odor which is commonly described as being similar to that of vanillin or cherry. For this reason it is commonly used in fragrances and artificial flavors.^[3] 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).^[10] Perfumers began to use the fragrance for the first time by the early 1880s.^[11] It is commonly used to add vanilla or almond nuances, generally imparting balsamic, powdery, and floral aspects to a scent's character.^[12]

Piperonyl acetate is a synthetic cherry flavoring.^[13]

Use in MDMA manufacture

Due to their role in the manufacture of MDMA, safrole, isosafrole, and piperonal are Category I precursors under regulation no. 273/2004 of the European Community.^[14]