Phenylacetic acid

Phenylacetic acid (conjugate base phenylacetate), also known by various synonyms, is an organic compound containing a phenyl functional group and a carboxylic acid functional group. It is a white solid with a strong honey-like odor. Endogenously, it is a catabolite of phenylalanine. As a commercial chemical, because it can be used in the illicit production of phenylacetone (used in the manufacture of substituted amphetamines), it is subject to controls in countries including the United States and China.^[3]

Phenylacetic acid

Names
Preferred IUPAC name Phenylacetic acid
Systematic IUPAC name 2-Phenylethanoic acid
Other names α-Toluic acid Benzeneacetic acid 2-Phenylacetic acid β-Phenylacetic acid
Identifiers
CAS Number	103-82-2 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1099647
ChEBI	CHEBI:30745 Y
ChEMBL	ChEMBL1044 Y
ChemSpider	10181341 Y
DrugBank	DB09269
ECHA InfoCard	100.002.862
EC Number	203-148-6
Gmelin Reference	68976
KEGG	C07086
PubChem CID	999
RTECS number	AJ2430000
UNII	ER5I1W795A Y
CompTox Dashboard (EPA)	DTXSID2021656
InChI InChI=1S/C8H8O2/c9-8(10)6-7-4-2-1-3-5-7/h1-5H,6H2,(H,9,10) Y Key: WLJVXDMOQOGPHL-UHFFFAOYSA-N Y InChI=1/C8H8O2/c9-8(10)6-7-4-2-1-3-5-7/h1-5H,6H2,(H,9,10) Key: WLJVXDMOQOGPHL-UHFFFAOYAR
SMILES O=C(O)Cc1ccccc1
Properties
Chemical formula	C8H8O2
Molar mass	136.15 g/mol
Appearance	white solid
Odor	honey-like
Density	1.0809 g/cm3
Melting point	76 to 77 °C (169 to 171 °F; 349 to 350 K)
Boiling point	265.5 °C (509.9 °F; 538.6 K)
Solubility in water	15 g/L
Acidity (pKa)	4.31 (H2O)[1]
Magnetic susceptibility (χ)	-82.72·10−6 cm3/mol
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H318, H319
Precautionary statements	P264, P280, P305+P351+P338, P310, P337+P313
NFPA 704 (fire diamond)	2 1 0
Safety data sheet (SDS)	External MSDS
Legal status	BR: Class D1 (Drug precursors)[2]
Related compounds
Related compounds	Benzoic acid, Phenylpropanoic acid, Cinnamic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Occurrence

Phenylacetic acid has been found to be an active auxin (a type of plant hormone),^[4] found predominantly in fruits. However, its effect is much weaker than the effect of the basic auxin molecule indole-3-acetic acid. In addition the molecule is naturally produced by the metapleural gland of most ant species and used as an antimicrobial. It is also the oxidation product of phenethylamine in humans following metabolism by monoamine oxidase and subsequent metabolism of the intermediate product, phenylacetaldehyde, by the aldehyde dehydrogenase enzyme; these enzymes are also found in many other organisms.

Preparation

This compound may be prepared by the hydrolysis of benzyl cyanide:^[5][6]

Phenylacetic acid

Reactions

Phenylacetic acid undergoes ketonic decarboxylation to form ketones.^[7] It can be condensed with itself to form dibenzyl ketone, or with a large excess of another carboxylic acid (in the form of an acid anhydride), such as with acetic anhydride to form phenylacetone.

Applications

Phenylacetic acid is used in some perfumes, as it possesses a honey-like odor even in low concentrations. It is also used in penicillin G production and diclofenac production. It is also employed to treat type II hyperammonemia to help reduce the amounts of ammonia in a patient's bloodstream by forming phenylacetyl-CoA, which then reacts with nitrogen-rich glutamine to form phenylacetylglutamine. This compound is then excreted from the patient's body. It's also used in the illicit production of phenylacetone, which is used in the manufacture of methamphetamine.

The sodium salt of phenylacetic acid, sodium phenylacetate, is used as a pharmaceutical drug for the treatment of urea cycle disorders, including as the combination drug sodium phenylacetate/sodium benzoate (Ammonul).^[8]

Phenylacetic acid is used in the preparation of and derived from several pharmaceutical drugs, including camylofin, bendazol, triafungin, phenacemide, lorcainide, phenindione, phenelzine and cyclopentolate.^{[citation needed]}

In popular culture

In the crime drama Breaking Bad, phenylacetic acid is featured twice as a precursor to methamphetamine, first in the episode titled "A No-Rough-Stuff-Type Deal", then in "Salud".^[9]

See also

• Cathinone
• Methyl phenylacetate

References

1. Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. pp. 5–89. ISBN 978-1498754286.
2. Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-15.
3. "List of Regulated Drug Precursor Chemicals in China". Archived from the original on 17 August 2015. Retrieved 27 April 2015.
4. Wightman, F.; Lighty, D. L. (1982). "Identification of phenylacetic acid as a natural auxin in the shoots of higher plants". Physiologia Plantarum. 55 (1): 17–24. doi:10.1111/j.1399-3054.1982.tb00278.x.
5. Adams R.; Thal, A. F. (1922). "Phenylacetic acid". Organic Syntheses. 2: 59; Collected Volumes, vol. 1, p. 436.
6. Wenner, W. (1952). "Phenylacetamide". Organic Syntheses. 32: 92; Collected Volumes, vol. 4, p. 760.
7. Siegel, Hardo; Eggersdorfer, Manfred (2000). "Ketones". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a15_077. ISBN 9783527306732.
8. "Sodium Phenylacetate and Sodium Benzoate Monograph for Professionals". Drugs.com. Retrieved 16 November 2019.
9. Harnisch, Falk; Salthammer, Tunga. "The Chemistry of Breaking Bad". Chemistry Views. Chemistry Europe. Archived from the original on 8 February 2024.