phenylacetate

Phenylacetate typically refers to the phenylacetate ion, the conjugate base of phenylacetic acid. Its formula in solution is C6H5CH2COO−, and it forms salts such as sodium phenylacetate. Phenylacetic acid has a pKa around 4.3, so the phenylacetate anion is the predominant form at neutral to basic pH.

The anion features a benzene ring linked through a methylene group to a carboxylate moiety. The negative charge is delocalized over the carboxylate group, while the phenyl group imparts hydrophobic character. In salts, the compound is generally more soluble in water than the neutral acid.

Preparation and reactions: Phenylacetate is typically prepared by deprotonating phenylacetic acid with bases such as sodium hydroxide, sodium hydride, or organolithium reagents. In organic synthesis, the phenylacetate carbanion acts as a nucleophile at the methylene carbon, enabling alkylation to form substituted phenylacetates and related derivatives. It can participate in various carbon–carbon bond-forming reactions and serves as a building block for more complex molecules.

Uses and applications: In chemistry, phenylacetate and its salts are used as intermediates in the synthesis of pharmaceuticals and fine chemicals. Medically, sodium phenylacetate is used as an ammonia scavenger in the management of urea cycle disorders, where it conjugates with glutamine to form phenylacetylglutamine, which is excreted in urine and helps reduce blood ammonia levels.

Related compounds include phenylacetic acid (the parent carboxylic acid), phenylacetate esters, and phenylacetylglutamine, a metabolic product formed in ammonia detoxification pathways. Safety data and handling depend on the specific salt or ester form.