Acetylated hydroxynaphthazarin di-and trithioglucosides structurally related to echinochrome were synthesized. Their deacetylation by the action of sodium methoxide in methanol and the effect of hydroxy groups on this process were studied. Water-soluble echinochrome thioglucosides were synthesized for the first time.Naphthoquinones are widespread in nature, and they exhibit diverse physiological activity [1, 2]. Among these compounds, polyhydroxynaphthoquinones of the naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) series occupy a particular place. Due to specificity of their structure, they are capable of effectively trapping free radicals and binding Fe 2+ ions responsible for the formation of active oxygen species [3,4]; excess concentration of the latter in an organism promotes development of various pathological states [5].Echinochrome (I, 6-ethyl-2,3,5,7,8-pentahydroxy-1,4-naphthoquinone) is a pigment isolated from the sea urchin shell (Echinodea); it was used as active substance of the drug Gistokhrom for the treatment of eye injuries and burns, as well as of myocardial infarction [6]. The results of recent experiments in animals showed that Gistokhrom is also effective in the treatment of hemorrhagic stroke [7,8]. Unfortunately, echinochrome is poorly soluble in water. In order to improve the solubility and bioavailability, echinochrome was converted into the corresponding tris-Oglucoside [9]. However, the latter turned out to be unstable: it decomposed shortly after isolation.S-Glycosides are known to be more stable toward acids and bases than their O-glycoside analogs [10]. It was shown previously that chlorine atoms in the naphthazarin core are readily replaced by acetylglucoside residues under conditions of base catalysis [11]. It was also found that nucleophilic addition of chlorine atoms is accompanied by Michael 1,4-addition of thiols to the quinoid ring [12].The present article describes the synthesis of acetylated naphthazarin S-glucosides that are structurally related to echinochrome and deacetylation of the acetylglucosides by the action of sodium methoxide, which afforded stable water-soluble thioglucosides of the echinochrome series; the effect of hydroxy groups in the naphthazarin core on the deacetylation process was also studied.