Piperonyl aldehyde

Chemical properties

white crystalline solid

Chemical properties

Heliotropin occurs in a number of essential oils, but only in low concentrations. It forms white crystals (mp 37°C) with a sweet, floral, slightly spicy, heliotrope-like odor.

Chemical properties

Piperonal has a sweet, flowery odor reminiscent of heliotrope and a bittersweet taste.

Occurrence

Reported found in the essential oils of Robinia pseudo-acacia and Eryngium poterium; in the oils of Spirea ulmaria and of leaves of Doryphora sassafras; also reported found in Tahitian and Bourbon vanilla, camphor wood oil, violet flowers concrete and absolute, burley tobacco, rabbiteye blueberry, melon, pepper, cooked chicken, sherry and dill.

The Uses of Piperonyl aldehyde

Piperonal is an impurity of Tadalafil (T004500). Tadalafil impurity A.

The Uses of Piperonyl aldehyde

In perfumery, in cherry and vanilla flavors, in organic syntheses.

The Uses of Piperonyl aldehyde

Piperonal is used as fragrance and flavoring agent.

Definition

ChEBI: An arenecarbaldehyde that is 1,3-benzodioxole substituted by a formyl substituent at position 5. It has been isolated from Piper nigrum.

Preparation

Heliotropin is produced by two main routes:
1) From isosafrole: For many years, oxidative cleavage of isosafrole was the only route applicable on an industrial scale. Isosafrole [120-58-1] is obtained by isomerization from safrole [94-59-7], which can be isolated from (Chinese) sassafras oil . Examples of oxidants that give good yields of heliotropin are chromium(VI) salts, oxygen, and ozone.
This method is still used currently, but the destructive exploitation of sassafras trees in Southeast Asia has led to a strong decline in the availability of sassafras oil and thus of safrole/isosafrole.
2) From catechol: Several routes have recently been developed for the synthesis of heliotropin from catechol. In one such route, catechol is converted into 3,4-dihydroxymandelic acid with glyoxylic acid in an alkaline medium in the presence of aluminum oxide. 3,4-Dihydroxymandelic acid is oxidized to the corresponding keto acid (e.g., with copper-(II) oxide), which is decarboxylated to 3,4-dihydroxybenzaldehyde. The latter product is converted into heliotropin, for example, by reactionwith methylene chloride in the presence of quaternary ammonium salts.
In another route, catechol is first reacted with methylene chloride and converted into 1,2-methylenedioxybenzene . Reaction with glyoxylic acid in strongly acidic media yields 3,4-methylenedioxymandelic acid . Subsequent oxidation and decarboxylation with nitric acid afford heliotropin.
Alternative routes that start from 1,2-methylenedioxybenzene and use piperonyl chloride as intermediate have been described .

Aroma threshold values

Detection: 62 ppb to 1 ppm. Aroma characteristics at 1.0%: sweet, anise-like, almond vanilla, floral, black cherry pit, berry raspberry, powdery coumarin-like with a hint of hay.

Taste threshold values

Taste characteristics at 10 to 50 ppm: ripe black cherry fleshy, ripe berry, sweet, macaroon, Jordan almond, creamy vanilla, spicy cream soda, courmarin, slight floral with hay nuances.

Synthesis Reference(s)

Canadian Journal of Chemistry, 64, p. 225, 1986 DOI: 10.1139/v86-039
The Journal of Organic Chemistry, 48, p. 4053, 1983 DOI: 10.1021/jo00170a036
Tetrahedron Letters, 33, p. 5909, 1992 DOI: 10.1016/S0040-4039(00)61086-9

General Description

Colorless lustrous crystals.

Air & Water Reactions

Slightly water soluble .

Reactivity Profile

Piperonyl aldehyde is an aldehyde. Aldehydes are frequently involved in self-condensation or polymerization reactions. These reactions are exothermic; they are often catalyzed by acid. Aldehydes are readily oxidized to give carboxylic acids. Flammable and/or toxic gases are generated by the combination of aldehydes with azo, diazo compounds, dithiocarbamates, nitrides, and strong reducing agents. Aldehydes can react with air to give first peroxo acids, and ultimately carboxylic acids. These autoxidation reactions are activated by light, catalyzed by salts of transition metals, and are autocatalytic (catalyzed by the products of the reaction). The addition of stabilizers (antioxidants) to shipments of aldehydes retards autoxidation. Piperonyl aldehyde is sensitive to light. Piperonyl aldehyde may react with oxidizing materials.

Fire Hazard

Flash point data for Piperonyl aldehyde are not available. Piperonyl aldehyde is probably combustible.

Flammability and Explosibility

Not classified

Safety Profile

Moderately toxic by ingestion and intraperitoneal routes. Can cause central nervous system depression. A human skin irritant. Mutation data reported. Combustible when exposed to heat or flame; can react with oxidizing materials. See also ALDEHYDES.

Synthesis

By the oxidation of isosafrole with potassium dichromate and sulfuric acid and subsequent steam distillation of piperonal

Metabolism

In the animal body heliotropin undergoes the expected metabolic reaction involving oxidation to the corresponding acid (Williams, 1959).

Purification Methods

Crystallise piperonal from aqueous 70% EtOH or EtOH/water. [Beilstein 19/4 V 225.]