Spinochrome D

 ( 1,4-naphthoquinones ) 

Spinochrome D ( 2,3,5,6,8-pentahydroxy-1,4-naphthoquinone) is an organic compound with formula , formally derived from naphthoquinone through the replacement of five hydrogen atoms by hydroxyl (OH) groups.

Spinochrome D occurs naturally as a brownish red pigment in the exoskeleton 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.

• Spinochrome B
• Spinochrome E