Carminic acid

Carminic acid^[1]

Names
IUPAC names 7-α-D-Glucopyranosyl-9,10-dihydro- 3,5,6,8-tetrahydroxy-1-methyl-9,10- dioxoanthracenecarboxylic acid
Other names Carminic acid C.I. Natural Red 4 C.I. 75470 CI 75470
Identifiers
CAS Number	1260-17-9
3D model (Jmol)	Interactive image
ChEBI	CHEBI:78310
ChEMBL	ChEMBL263094
ChemSpider	14068
ECHA InfoCard	100.013.658
E number	E120 (colours)
KEGG	C11254
UNII	CID8Z8N95N
InChI InChI=1S/C22H20O13/c1-4-8-5(2-6(24)9(4)22(33)34)13(25)10-11(15(8)27)16(28)12(18(30)17(10)29)21-20(32)19(31)14(26)7(3-23)35-21/h2,7,14,19-21,23-24,26,28-32H,3H2,1H3,(H,33,34)/t7-,14-,19+,20-,21-/m1/s1 Key: DGQLVPJVXFOQEV-NGOCYOHBSA-N InChI=1/C22H20O13/c1-4-8-5(2-6(24)9(4)22(33)34)13(25)10-11(15(8)27)16(28)12(18(30)17(10)29)21-20(32)19(31)14(26)7(3-23)35-21/h2,7,14,19-21,23-24,26,28-32H,3H2,1H3,(H,33,34)/t7-,14-,19+,20-,21-/m1/s1 Key: DGQLVPJVXFOQEV-NGOCYOHBBS
SMILES O=C(O)c2c(c3C(=O)c1c(O)c(c(O)c(O)c1C(=O)c3cc2O)[C@H]4O[C@@H]([C@@H](O)[C@H](O)[C@H]4O)CO)C
Properties
Chemical formula	C22H20O13
Molar mass	492.38 g/mol
Density	? g/cm^3
Melting point	120 °C (248 °F; 393 K) (decomposes)
Acidity (pKa)	3.39, 5.78, 8.35, 10.27, 11.51[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Carminic acid (C₂₂H₂₀O₁₃) is a red glucosidal hydroxyanthrapurin that occurs naturally in some scale insects, such as the cochineal, Armenian cochineal, and Polish cochineal. The insects produce the acid as a deterrent to predators. Carminic acid is the colouring agent in carmine. Synonyms are C.I. 75470 and C.I. Natural Red 4.

The chemical structure of carminic acid consists of a core anthraquinone structure linked to a glucose sugar unit. Carminic acid was first synthesized by organic chemists in 1991.^[3]

References

1. Merck Index, 11th Edition, 1850.
2. Atabey, Hasan; Sari, Hayati; Al-Obaidi, Faisal N. (28 April 2012). "Protonation Equilibria of Carminic Acid and Stability Constants of Its Complexes with Some Divalent Metal Ions in Aqueous Solution". Journal of Solution Chemistry. 41 (5): 793–803. doi:10.1007/s10953-012-9830-7.
3. Allevi, P.; et al. (1991). "The First Total Synthesis of Carminic Acid". Journal of the Chemical Society-Chemical Communications. 18: 1319–1320. doi:10.1039/C39910001319.