Hexahydroxy-1,4-naphthalenedione
2,3,5,6,7,8-Hexahydroxy-1,4-naphthalenedione, also called hexahydroxynaphthoquinone or spinochrome E, is an organic compound with formula. It is formally derived from naphthoquinone through replacement of all six hydrogen atoms by hydroxyl groups. The numerical prefixes "2,3,5,6,7,8" are superfluous, since there is no other hexahydroxy derivative of 1,4-naphthoquinone.
The substance forms red micro-needles which
do not melt below 300 °C, and can be sublimed in vacuum at about 265 °C.
The compound occurs in the shell and spines of the sea urchins Paracentrotus lividus and Psammechinus miliaris.
The compound can be produced by condensation of 3,4,5,6-tetramethoxyphthalaldehyde with glyoxal.