Gentisic acid
Template:Chembox Gentisic acid is a dihydroxybenzoic acid. It is a derivative of benzoic acid and a minor (1%) product of the metabolic break down of aspirin, excreted by the kidneys.[1]
It is also found in the African tree Alchornea cordifolia and in wine.[2]
Production
Gentisic acid is produced by carboxylation of hydroquinone.[3]
- C6H4(OH)2 + CO2 → C6H3(CO2H)(OH)2
This conversion is an example of a Kolbe–Schmitt reaction.
Alternatively the compound can be synthesized from salicylic acid via Elbs persulfate oxidation.[4][5]
Reactions
In the presence of the enzyme gentisate 1,2-dioxygenase, gentisic acid reacts with oxygen to give maleylpyruvate:
- 2,5-dihydroxybenzoate + O2 maleylpyruvate
Applications
As a hydroquinone, gentisic acid is readily oxidised and is used as an antioxidant excipient in some pharmaceutical preparations.
In the laboratory, it is used as a sample matrix in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry,[6] and has been shown to conveniently detect peptides incorporating the boronic acid moiety by MALDI.[7]
References
Cited sources
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- ↑ Hudnall, Phillip M. (2005) "Hydroquinone" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Wiley-VCH, Weinheim. Template:Doi.
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