p-Anisaldehyde

Description

p-Methoxybenzaldehyde has a characteristic hawthorne odor and a pungent, anise-like flavor. It has a bitter flavor above 30 - 40 ppm. May be prepared by methylation and oxidation of p-cresol and also by oxidation of anethole.

Chemical properties

p-Anisaldehyde is a colorless to slightly yellowish liquid with a sweet, mimosa, hawthorn odor. It occurs in many essential oils, often together with anethole. It can be hydrogenated to anise alcohol and readily oxidizes to anisic acid when exposed to air. It is miscible in alcohol, ether, and most fixed oils, soluble in propylene glycol, insoluble in glycerin, water, and mineral oil.

Occurrence

Reported found in essential oils and extracts of vanilla, Acacia farmesiana Willd., Magnoila salicifolia Maxim., Erica arborea, Pirus communis, Boswellia serrata, and others; also in anise, fennel and star anise (especially when aged due to the oxidation of anethole), cranberry, black currant, cinnamon and basil.

The Uses of p-Anisaldehyde

p-Anisaldehyde is a flavoring agent that is a colorless or faintly yellow liquid, hawthorn-like odor. It is miscible in alcohol, ether, and most fixed oils, soluble in propylene glycol, insoluble in glycerin, water, and mineral oil. It is obtained by synthesis. It is also termed anise aldehyde and p-methoxybenzaldehyde.

The Uses of p-Anisaldehyde

Perfumery and toilet soaps; odor resembles that of coumarin, but the aldehyde must be mixed with other odorous substances to yield an agreeable odor. Also used in organic syntheses.

The Uses of p-Anisaldehyde

4-Methoxybenzaldehyde is widely utilized in the fragrance and flavor industry. It finds application as an important intermediate in the synthesis of other organic compounds, perfumes and pharmaceuticals like antihistamines. It is also used in the preparation of agrochemicals, dyes and plastic additives. A solution of para-anisaldehyde with acid and ethanol is used as stain in thin layer chromatography (TLC), which provides easy identification of different compounds. Concentrations usually 0.5 to 30 ppm in finished goods, and up to 75 ppm in chewing gum. The flavor threshold for Anisaldehyde on the average panel person is about 0.2 ppm. (Single chemical in Sugar water).

Preparation

By methylation and oxidation of p-cresol and also by oxidation of anethole.

Definition

ChEBI: P-methoxybenzaldehyde is a member of the class of benzaldehydes consisting of benzaldehyde itself carrying a methoxy substituent at position 4. It has a role as an insect repellent, a human urinary metabolite, a plant metabolite and a bacterial metabolite.

Aroma threshold values

Aroma characteristics at 1.0%: sweet powdery, spicy creamy, fruity, vanilla and hay-like. Coumarin, almond, anisic with berry nuances.

Taste threshold values

Taste characteristics at 5 to 10 ppm: sweet powdery, vanilla creamy, spice anise, nutty, cherry pit and almond-like nuances.

Synthesis Reference(s)

Chemical and Pharmaceutical Bulletin, 42, p. 1041, 1994 DOI: 10.1248/cpb.42.1041
Tetrahedron Letters, 43, p. 1395, 2002 DOI: 10.1016/S0040-4039(02)00027-8

General Description

p-anisaldehyde is an aromatic aldehyde commonly found in anise seed oil. It shows acaricidal activity and is primarily used, as a lead compound for the development of new agents for the selective control of house dust mites.

Flammability and Explosibility

Non flammable

Biochem/physiol Actions

Taste at 5-10 ppm

Safety Profile

Moderately toxic by ingestion. A skin irritant. Mutation data reported. Combustible liquid. When heated to decomposition it emits acrid smoke and irritating fumes

Decomposition

When heated to decomposition it emits acrid smoke and irritating fumes. Hazardous decomposition products formed under fire conditions: Carbon oxides.

Hazard

Prolonged or repeated contact may dry/defat the skin and cause irritation. Ingestion: May cause irritation of the digestive tract. May be harmful if swallowed. Inhalation: May cause respiratory tract irritation.

Metabolism

Anisic aldehyde undergoes a very slight degree of demethylation with oxidation of its aldehyde group to an acid group, the major metabolite excreted being anisic acid (Williams, 1959).

Purification Methods

Wash the aldehyde with saturated aqueous NaHCO3, then H2O, steam distil, extract the distillate with Et2O, dry (MgSO4) the extract, filter and distil this under a vacuum and N2. Store it in glass ampules under N2 in the dark. [Beilstein 8 IV 252.]