Abstract 2, 3, 5, 8-Tetrahydroxy-1, 4-naphthoquinone (spinazarin) and 6-ethyl-2, 3, 5, 8- tetrahydroxy-1, 4-naphthoquinone (ethylspinazarin) were first isolated from the sea urchin Scaphechinus mirabilis. The structures of spinazarins were established based on analysis of spectroscopic data. A preparative synthetic route to ethylspinazarin was proposed.
