Structure of Acid-Stable Carmine - ResearchGate.
Carminic acid is a tetrahydroxyanthraquinone that is that is 1,3,4,6-tetrahydroxy-9,10-anthraquinone substituted by a methyl group at position 8, a carboxy group at position 7 and a 1,5-anhydro-D-glucitol moiety at position 2 via a C-glycosidic linkage. It is a natural dye isolated from several insects such as Dactylopius coccus.Carminic acid is soluble in water, alcohol, ether, acid and alkaline solutions and insoluble in benzene, chloroform and petroleum. Addition of alkalies or neutral lead acetate, carminic acid changes from scarlet red shade to bluish red. Addition of saturated solution of uranium acetate, which is a characteristic test for carminic acid, gives a.Methylation afforded the corresponding trimethyl ethers, which by reductive methylation gave the required pentamethoxy compounds. By known steps 6-deoxycarminic acid tetraacetate was converted into the 5,8,9,10-bisquinone, acetoxylation of which gave carminic acid octaacetate. Acidic hydrolysis afforded carminic acid.
Carminic acid has been used as a colorant even in the ancient civilizations be it the Egyptian, or the Maya or the Inca. At one point the worth of this color was more than that of real gold. It is used as a food colorant, a dye and body colorant. Canary Islands and Peru are the major centers for the cultivation of these carminic acid producing.A variety of commercial samples of carmine and carminic acid were analysed qualitatively by gel-filtration on Sephadex LH20 with salty dimethylformamide as eluent, and by thin layer chromatography on cellulose layers using acetone-acetic acid-water, 1:1:1 by volume, as developing solvent. Quantitative assays of carminic acid (when necessary released from the carmine by acid hydrolysis) were.
Synthesis of 15N-4-aminocarminic acid clearly demonstrated that “acid-stable carmine” is not the ammonium salt of carminic acid, which is approved as food additive in the European Union. In.
