S-2-Amino-5-(dimethylammonio)phenyl sulfothioate

Abstract

The title compound, C8H12N2O3S2, has been isolated as an intermediate in the synthesis of methylene blue dye, the best known phenothiazine dye, and structurally characterized as a zwitterion. The crystal structure is dominated by intermolecular N—H...O hydrogen bonds between the amine and sulfothioate groups, with graph-set motif C(9)R22(8), involving antiparallel chains and a centrosymmetric eight-membered ring. A hydrogen bond with graph-set motif R22(14) between the ammonium and sulfothioate groups completes the two-dimensional network in the ab plane. Intermolecular C—H...O hydrogen bonds are also present in the crystal.