2-Mercaptoethanol → 2-Hydroxyethylthio-6-methyl-1,4-benzoquinone

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Reaction Steps

Methyl-p-benzoquinone 12.2 g, 0.1 mole) and 2-mercaptoethanol (3.9 g, 0.05 mole) are mixed in absolute ethanol (70 ml) under nitrogen and with stirring. The temperature rises to 50° C. The mixture is cooled in a bath of ice-water and left to stand, with stirring, for 2 hours at ambient temperature. The solution is concentrated under vacuum and the oil obtained is chromatographed on Silica 60 (eluent: dichloromethane). According to 1H and 13C NMR, a first fraction (3 g) is a 50/50 mixture of two products: 2-hydroxyethylthio-5-methyl-1,4-benzoquinone and 2-hydroxyethylthio-6-methyl-1,4-benzoquinone. A second fraction gives the expected product:

Provenance & Evidence