Title: Kermesic Acid
CAS Registry Number: 18499-92-8
CAS Name: 9,10-Dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo-2-anthracenecarboxylic acid
Additional Names: C.I. Natural Red 3; C.I. 75460
Molecular Formula: C16H10O8
Molecular Weight: 330.25
Percent Composition: C 58.19%, H 3.05%, O 38.76%
Literature References: Principle constituent of kermes, one of the oldest known insect dyes. Isoln and characterization: O. Dimroth, Ber. 43, 1387 (1910); O. Dimroth, W. Scheurer, Ann. 399, 43 (1913). Structure: O. Dimroth, R. Fick, Ann. 411, 315 (1916). Revised structure: D. D. Gadgil et al., Tetrahedron Lett. 1968, 2223. Synthesis: D. W. Cameron et al., Chem. Commun. 1978, 688; eidem, Aust. J. Chem. 34, 2401 (1981).
Properties: Dark red rosettes from acetic acid, mp >320° (dec). Absorption max: 276, 312, 498 nm (log e 4.52, 4.12, 3.96). Slightly sol in cold water; sol in hot water (yellowish-red soln). Violet-red in conc H2SO4, turning blue on addn of boric acid. Violet in aq NaOH.
Melting point: mp >320° (dec)
Absorption maximum: Absorption max: 276, 312, 498 nm (log e 4.52, 4.12, 3.96)
Use: As brilliant scarlet dye. |