Pigments of marine animals. IX. A synthesis of 6-Acetyl-2,3,5,7-tetrahydroxy-1,4-naphthoquinone; Its status as an echinoid pigment

Abstract

6-Acetyl-2,3,5,7-tetrahydroxy-1,4-naphthoquinone (1) is obtained from 1,2,3,4,5,7-hexaacetoxynaphthalene by Fries rearrangement, hydrolysis, and oxidation, but differs in properties from the substance described in the literature as a spine pigment of Echinothrix diadema Linn., E. calamaris Pallis, and Echinometra oblonga Blainville and claimed to be (1). The synthetic quinone (1) is very probably identical with Lederer's spinochrome G from Paracentrotus lividus Lamarck. Paperchromatographic data for various echinoid pigments and other naphthoquinones is presented.