Spinochrome D (2,3,5,6,8-pentahydroxy-1,4-naphthoquinone) is an organic compound with formula , formally derived from 1,4-naphthoquinone through the replacement of five hydrogen atoms by hydroxyl (OH) groups.
Spinochrome D occurs naturally as a brownish red pigment in the shell and spines of sea urchins such as the Japanese aka-uni (Pseudocentrotus depressus).Chika KURODA and Masae OKAJIMA (1967), Studies on the Derivatives of Naphthoquinones, XVIII. The pigments of sea urchins, XIII. Proc. Japan Acad., volume 43, pages 41--44. Online version accessed on 2010-02-01. It is soluble in diethyl ether and crystallizes as brownish red needles that sublime at 285−295 °C.
The compound gives a yellowish brown solution when treated with sodium hydroxide, a bluish green solution with ferric chloride, and a violet precipitate with lead acetate. It forms a five-fold acetate ester, ()5, that crystallizes from methanol as yellow needles that melt at 185−186 °C.
See also Spinochrome B Spinochrome E
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