Orsellinic acid explained

Orsellinic acid, more specifically o-orsellinic acid, is a phenolic acid. It is of importance in the biochemistry of lichens, from which it can be extracted.^[1] It is a common subunit of depsides.

Chemistry

It can be prepared by the oxidation of orsellaldehyde,^[2] or through a Michael adduct:

This can also be produced by the hydrolysis of either everninic acid or ramalic acid by boiling with barium hydroxide. When crystallized from acetone it forms crystalline needles with a melting point of 176 °C.^[3] It also forms a crystalline hydrate with a melting point of 186-189 °C when crystallized from water.^[3]

Orsellinic acid is biosynthesized by a polyketide pathway.

Notes and References

1. Nolan, T. J. . Keane, J. . Davidson, V. E. . Chemical constituents of the lichen Parmelia latissima Fee . Scientific Proceedings of the Royal Dublin Society, Series A . 1940 . 22 . 237–239.
2. 10.1021/ol030109m . Total Synthesis of the Highly Potent Anti-HIV Natural Product Daurichromenic Acid along with Its Two Chromane Derivatives, Rhododaurichromanic Acids A and B . Kang, Ying . Mei, Yan . Du, Yuguo . Jin, Zhendong . Organic Letters . 2003 . 5 . 23 . 4481–4484 . 14602030.
3. Book: Merck Index . 11th . 1179-1180 . 7009. o-Orsellinic acid.