Kermesic acid

Kermesic acid
Names
IUPAC name
3,5,6,8-Tetrahydroxy-1-methyl-9,10-dioxoanthracene-2-carboxylic acid
Other names
  • C.I. Natural Red 3
  • 1-Methyl-2-carboxy-3,5,6,8-tetrahydroxyanthraquinone
Identifiers
3D model (JSmol)
UNII
  • CC1=C2C(=CC(=C1C(=O)O)O)C(=O)C3=C(C2=O)C(=CC(=C3O)O)O
Properties
C16H10O8
Molar mass 330.248 g·mol−1
Appearance Red crystalline needles[1]
Melting point 320 °C (608 °F; 593 K) (decomp.)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Kermesic acid is an anthraquinone derivative and the main component of the red dye kermes (false carmine). The compound is the aglycone of carminic acid, the main component of true carmine. As a dye, it is known as Natural Red 3.

Kermesic acid, like carminic acid and the laccaic acids, is an insect dye obtained from scale insects. Kermesic acid is found in insects of the genus Kermes. It is the only colored component of the dye kermes.[2]

The chemical structure of kermesic acid was elucidated by Otto Dimroth in 1916.[3][4]

  1. ^ a b "Kermessäure". Römpp's Chemistry Lexicon.
  2. ^ Mark C. Whiting (1981). "The dyes in early oriental carpets". In Society of German Chemists (ed.). Chemistry in our time. Weinheim: Verlag Chemie GmbH. pp. 179–189. 15th year, no. 6.
  3. ^ Brigl, P. (1921). Die chemische Erforschung der Naturfarbstoffe. doi:10.1007/978-3-663-05096-4. ISBN 978-3-663-03907-5.
  4. ^ Dimroth, Otto; Fick, Reinhold (1916). "I. Über den Farbstoff des Kermes". Justus Liebigs Annalen der Chemie. 411 (3): 315–338. doi:10.1002/jlac.19164110303.