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|Section2= |Section3= }} 2,3,5,6,8-Pentahydroxy-1,4-naphthalenedione, also called 2,3,5,6,8-pentahydroxy-1,4-naphthoquinone or spinochrome D, 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 == * Hexahydroxynaphthoquinone (spinochrome E) * 2,3,5,7-Tetrahydroxy-1,4-naphthoquinone (spinochrome B) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「2,3,5,6,8-Pentahydroxy-1,4-naphthalenedione」の詳細全文を読む スポンサード リンク
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