The treatment of chloranil (I) with alkali and 2-mercaptoethanol resulted not only in replacement of the chlorine atoms but also in reduction to form 2, 3, 5, 6-tetrakis (β- hydroxyethylmercapto)-1, 4-hydroquinone (II). The conditions for the preparation of 2, 3, 5, 6- tetrakis (β-chloroethylmercapto)-1, 4-hydroquinone (III) from II differed from those required for the preparation of a lower-melting compound (IV) from II by such a narrow margin that ...