Phenylglyoxylic acid is the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

with the formula C₆H₅C(O)CO₂H. The conjugate base, known as benzoylformate is the substrate of benzoylformate decarboxylase, a

thiamine diphosphate Thiamine pyrophosphate (TPP or ThPP), or thiamine diphosphate (ThDP), or cocarboxylase is a thiamine (vitamin B1) derivative which is produced by the enzyme thiamine diphosphokinase. Thiamine pyrophosphate is a cofactor that is present in all liv ...

-dependent

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

: :benzoylformate + H⁺ benzaldehyde + CO₂ It is a colourless solid with a melting point of 64–66 °C and is moderately acidic ( p''K''_a = 2.15). Phenylglyoxylic acid can be synthesized by oxidation of

mandelic acid Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C6H5CH(OH)CO2H. It is a white crystalline solid that is soluble in water and polar organic solvents. It is a useful precursor to various drugs. The molecule is chiral. T ...

with

potassium permanganate Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, that dissolves in water as K+ and , an intensely pink to purple solution. Potassium permanganate is widely used in the c ...

. An alternative synthesis involves

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolys ...

of benzoyl cyanide.

References

{{Reflist Carboxylic acids Phenyl compounds