Spinochrome B (2,3,5,7-tetrahydroxynaphthoquinone) is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

with formula , formally derived from 1,4-naphthoquinone through the replacement of four

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

atoms by

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

(OH) groups. Spinochrome B occurs naturally as

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

in the shell and spines of sea urchins such as the Japanese dull red species ''aka-uni'' (''

Pseudocentrotus depressus ''Pseudocentrotus depressus'', commonly known as the pink sea urchin, is a species of sea urchin, one of only two species in the genus ''Pseudocentrotus''. It was first described in 1864 by the American marine zoologist Alexander Agassiz as ' ...

''), the greenish-black ''murasaki-uni'' (''

Heliocidaris crassispina ''Heliocidaris'' is a genus of sea urchins, part of the familia Echinometridae. Characteristics This genus is typical of west Pacific Ocean (Japan to New Zealand), in particular in Australia. Some species are edible. List of species This ge ...

''), and the brown ''bafun-uni'' ('' Strongylocentrotus pulcherrimus'').Chika KURODA and Masae OKAJIMA (1958), ''Studies on the Derivatives of Naphthoquinones, XIV. The pigments of sea urchins, IX''. Proc. Japan Acad., volume 34, pages 616--618
Online version
accessed on 2010-02-01. Pigment M₂ is drawn as 2,3,6,8-thNQ but that is the same as 2,3,5,7-thNQ. The genus ''Heliocedaris'' should be ''Heliocidaris'' and the species ''purcherrmus'' should be ''pulcherrimus''.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

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

and crystallizes as bright red needles that

sublime Sublime may refer to: Entertainment * SuBLime, a comic imprint of Viz Media for BL manga * Sublime (band), an American ska punk band ** ''Sublime'' (album), 1996 * ''Sublime'' (film), a 2007 horror film * SubLime FM, a Dutch radio station dedic ...

above 200 °C. The compound gives a greenish yellow solution when treated with

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali ...

, a green solution with ferric chloride, and a green precipitate with lead acetate. It forms a fourfold

acetate An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...

ester, ()₄, that crystallizes from

as yellow needles that melt at 157 °C.

References

{{reflist 1,4-Naphthoquinones Catechols Resorcinols Tetrols Hydroxynaphthoquinones 3-Hydroxypropenals within hydroxyquinones

See also

References