2-phenylpropionaldehyde is also known as 2-phenylpropanal. It belongs to the family of phenylacetaldehydes. These are compounds containing a phenylacetaldehyde moiety, which consists of a phenyl group substituted at the second position by an acetalydehyde. 2- phenylpropionaldehyde is a naturally occurring compound in various foods including roasted nuts, cooked potatoes, cheese, wine, fruit, vegetables, coffee, tea, and cocoa. 2-phenylpropionaldehyde is used as a flavoring agent. Once absorbed, 2-phenylpropionaldehyde can be converted to phenyl-substituted carboxylic acids, which can be conjugated with glucuronic acid and excreted in the urine. 2-phenylpropionaldehyde can also undergo β- oxidation to benzoic acid or phenylacetic acid derivatives, which are conjugated with glycine or glutamine before being excreted in the urine.
[1] WHO Food Additives Series: 54, Safety evaluation of certain food additives
[2] https://webgate.ec.europa.eu
2-Phenylpropionaldehyde has an intense, green, floral odor reminiscent of hyacinth.
2-PHENYLPROPIONALDEHYDE identified in dried
mushroom, is a colorless liquid with a green hyacinth odor. Hydratropaldehyde
can be hydrogenated to hydratropic alcohol, which is also used to a limited extent by reaction of p-ethylbenzyl chloride and isobutyric aldehyde in the presence of
catalysts. The product is used in perfumes for, for example, household products.
Reported found in microbially fermented tea and some varieties of mushrooms.
2-Phenylpropionaldehyde is a precursor in the synthesis of N,N,β-Trimethyl-phenethylamine Hydrochloride (T796625).
ChEBI: 2-phenylpropanal is a member of the class of phenylacetaldehydes that is phenylacetaldehyde in which a hydrogen alpha to the aldehyde carbonyl group has been replaced by a methyl group. The major species at pH 7.3.
The most important synthetic route to 2-phenylpropionaldehyde is the rhodiumcatalyzed hydroformylation of styrene. The catalyst [HCo(CO)4] is unsuitable in this process because it favors the hydrogenation of styrene. The use of chiral rhodium complexes leads to the formation of optically active aldehydes when prochiral olefins, such as styrene, are used. Asymmetric hydroformylation, however, has so far found only small industrial application because of insufficient purity of the enantiomers. Other synthetic methods are the gas-phase oxidation of a-methylstyrene on Cu, Bi–Mo– P–SiO2, or Pd salt catalysts, the rearrangement of epoxidized a-methylstyrene, and the dehydrogenation of 2-phenyl-1-propanol on Ag catalysts at reaction temperatures of ca. 600 ℃.
By alkaline condensation of acetophenone and ethyl chloroacetate; also by distillation of methylphenyl ethylene glycol in
91% yields (under atmospheric pressure).
Journal of the American Chemical Society, 97, p. 5608, 1975
DOI: 10.1021/ja00852a062Organic Syntheses, Coll. Vol. 3, p. 733, 1955
Tetrahedron Letters, 15, p. 3059, 1974
2-Phenylpropionaldehyde is used in perfumes for its green hyacinth odor.
Flammability and Explosibility
Non flammable
Floralozone (IFF), Florazon (Symrise).
: Moderately toxic by
ingestion. Combustible liquid. When heated
to decomposition it emits acrid smoke and
irritating fumes. See also ALDEHYDES.
It may contain up to 15% of acetophenone. Purify it via the bisulfite addition compound [Lodge & Heathcock J Am Chem Soc 109 3353 1987] and see Chapter 2 for preparation and decomposition of bisulfite adducts. [Beilstein 7 IV 695.]
