Rahul Sharma (Editor)

Gentisic acid

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Formula
  
C7H6O4

Appearance
  
white to yellow powder

Molar mass
  
154.12 g/mol

Gentisic acid httpsuploadwikimediaorgwikipediacommonsthu

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.

Contents

It is also found in the African tree Alchornea cordifolia and in wine.

Production

Gentisic acid is produced by carboxylation of hydroquinone.

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.

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, and has been shown to conveniently detect peptides incorporating the boronic acid moiety by MALDI.

References

Gentisic acid Wikipedia