1.5.6.8- Tetrahydroxy-3-methylanthraquinone

Although kermisic acid had been obtained pure as early as 1895 (24), no investigation of the dye was undertaken until 1910 when stmctural elucidation studies by degradation methods began and it was deterrnined to have the stmctural formula (3). Synthetic stmctural proofs were done much later (25,26) and showed that (3) was incorrect. The actual stmcture of kermisic acid is (4), l,3,4,6-tetrahydroxy-7-carboxy-8-methylanthraquinone. 

Synonyms 2-Anthracenecarboxylic acid, 7-a-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1 -methyl-9,10-dioxo- 2-Anthracenecarboxylic acid, 7-p-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo- Cl 75470 Cl Natural red 4 Cochineal tincture 7-a-D-Glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1 -methyl-9,10-dioxo-2-anthracenecarboxylic acid 7-Glucopyranosyl 3,4,5,8-tetrahydroxy-1-methylanthraquinone-2-car1)oxy acid Natural red 4 Definition Naturally derived color from the insect, Coccus cacti, the essential constituent of carmine Empiricai C22H20O13... 

Glucopyranosyl 3,4,5,8-tetrahydroxy-1 -methylanthraquinone-2-carboxy acid. See Carminic acid... 

Di-Me ether [154661-65-1]. l,3,4,6-Tetrahydroxy-5,8-dimethoxy-2-methylanthraquinone C HiPs M 346.293 Constit. of the stem bark of Cassia javanica (Leguminosae). Yellow cryst. (petrol/EtOAc). Mp 192°. 

Glucopyranosyi-3,4,5,8-tetrahydroxy-1-methylanthraquinone-2-carboxylic acid. Carminic acid. Natural red 4. C. I. 75470. Cochineal [1260-17-9]... 

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