Dihydroxybenzoic acid

Dihydroxybenzoic acids (DHBA) are a type of phenolic acids.

There are six main compounds, having all the same molecular formula C₇H₆O₄. Those are:

• 2,3-Dihydroxybenzoic acid (2-Pyrocatechuic acid)
• 2,4-Dihydroxybenzoic acid (β-Resorcylic acid)
• 2,5-Dihydroxybenzoic acid (Gentisic acid)
• 2,6-Dihydroxybenzoic acid (γ-Resorcylic acid)
• 3,4-Dihydroxybenzoic acid (Protocatechuic acid)
• 3,5-Dihydroxybenzoic acid (α-Resorcylic acid)

Orsellinic acid is also a dihydoxybenzoic acid having an extra methyl group.

m-Dihydroxybenzoic acids, also called resorcylic acids, are part of the anaerobic metabolism of bacteria.^[1]

References

1. ^ Anaerobic metabolism of resorcyclic acids (m-dihydroxybenzoic acids) and resorcinol (1,3-benzenediol) in a fermenting and in a denitrifying bacterium. Claudia Kluge, Andreas Tschech and Georg Fuchs, Archives of microbiology, Volume 155, Number 1, pages 68-74, doi:10.1007/BF00291277