Carminic acid

Carminic acid
IUPAC name 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
Identifiers
CAS number	1260-17-9 Y
ChemSpider	14068 Y
UNII	CID8Z8N95N Y
KEGG	C11254 Y
ChEMBL	CHEMBL263094
Jmol-3D images	Image 1
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
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 Y Key: DGQLVPJVXFOQEV-NGOCYOHBSA-N Y 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
Properties
Molecular formula	C22H20O13
Molar mass	492.38 g/mol
Density	? g/cm3
Melting point	120 °C (decomp.)
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Carminic acid (C₂₂H₂₀O₁₃) is a red glucosidal hydroxyanthrapurin that occurs naturally in some scale insects, such as the cochineal and the 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.